10Base2


Описание :
10-Mbps baseband Ethernet specification using 50-ohm thin coaxial cable. 10Base2, which is part of the IEEE 802.3 specification, has a distance limit of 606.8 feet (185 meters) per segment.

Източник: Internetworking Terms and Acronyms, June 1999

10Base5


Описание :
10-Mbps baseband Ethernet specification using standard (thick) 50-ohm baseband coaxial cable. 10Base5, which is part of the IEEE 802.3 baseband physical layer specification, has a distance limit of 1640 feet (500 meters) per segment.

Източник: Internetworking Terms and Acronyms, June 1999

10BaseF


Описание :
10-Mbps baseband Ethernet specification that refers to the 10BaseFB, 10BaseFL, and 10BaseFP standards for Ethernet over fiber-optic cabling.

Вижте също: 10BaseFB, 10BaseFL, 10BaseFP.

Източник: Internetworking Terms and Acronyms, June 1999

10BaseFB


Описание :
10-Mbps baseband Ethernet specification using fiber-optic cabling. 10BaseFB is part of the IEEE 10BaseF specification. It is not used to connect user stations, but instead provides a synchronous signaling backbone that allows additional segments and repeaters to be connected to the network. 10BaseFB segments can be up to 1.24 miles (2000 meters) long.

Вижте също: 10BaseF.

Източник: Internetworking Terms and Acronyms, June 1999

10BaseFL


Описание :
10-Mbps baseband Ethernet specification using fiber-optic cabling. 10BaseFL is part of the IEEE 10BaseF specification and, while able to interoperate with FOIRL, is designed to replace the FOIRL specification. 10BaseFL segments can be up to 3280 feet (1000 meters) long if used with FOIRL, and up to 1.24 miles (2000 meters) if 10BaseFL is used exclusively.

Вижте също: 10BaseF и FOIRL.

Източник: Internetworking Terms and Acronyms, June 1999

10BaseFP


Описание :
10-Mbps fiber-passive baseband Ethernet specification using fiber-optic cabling. 10BaseFP is part of the IEEE 10BaseF specification. It organizes a number of computers into a star topology without the use of repeaters. 10BaseFP segments can be up to 1640 feet (500 meters) long.

Вижте също: 10BaseF.

Източник: Internetworking Terms and Acronyms, June 1999

10BaseT


Описание :
10-Mbps baseband Ethernet specification using two pairs of twisted-pair cabling (Category 3, 4, or 5): one pair for transmitting data and the other for receiving data. 10BaseT, which is part of the IEEE 802.3 specification, has a distance limit of approximately 328 feet (100 meters) per segment.

Източник: Internetworking Terms and Acronyms, June 1999

10Broad36


Описание :
10-Mbps broadband Ethernet specification using broadband coaxial cable. 10Broad36, which is part of the IEEE 802.3 specification, has a distance limit of 2.24 miles (3600 meters) per segment. See also Ethernet and IEEE 802.3.

Източник: Internetworking Terms and Acronyms, June 1999

100BaseFX


Описание :
100-Mbps baseband Fast Ethernet specification using two strands of multimode fiber-optic cable per link. To guarantee proper signal timing, a 100BaseFX link cannot exceed 1312 feet (400 meters) in length. Based on the IEEE 802.3 standard.

Вижте също: 100BaseX.

Източник: Internetworking Terms and Acronyms, June 1999

100BaseT


Описание :
100-Mbps baseband Fast Ethernet specification using UTP wiring. Like the 10BaseT technology on which it is based, 100BaseT sends link pulses over the network segment when no traffic is present. However, these link pulses contain more information than those used in 10BaseT. Based on the IEEE 802.3 standard.

Вижте също: 10BaseT.

Източник: Internetworking Terms and Acronyms, June 1999

100BaseT4


Описание :
100-Mbps baseband Fast Ethernet specification using four pairs of Category 3, 4, or 5 UTP wiring. To guarantee proper signal timing, a 100BaseT4 segment cannot exceed 328 feet (100 meters) in length. Based on the IEEE 802.3 standard.

Източник: Internetworking Terms and Acronyms, June 1999

100BaseTX


Описание :
100-Mbps baseband Fast Ethernet specification using two pairs of either UTP or STP wiring. The first pair of wires is used to receive data; the second is used to transmit. To guarantee proper signal timing, a 100BaseTX segment cannot exceed 328 feet (100 meters) in length. Based on the IEEE 802.3 standard.

Вижте също: 100BaseX

Източник: Internetworking Terms and Acronyms, June 1999

100BaseX


Описание :
100-Mbps baseband Fast Ethernet specification that refers to the 100BaseFX and 100BaseTX standards for Fast Ethernet over fiber-optic cabling. Based on the IEEE 802.3 standard.

Вижте също: 100BaseFX и 100BaseTX.

Източник: Internetworking Terms and Acronyms, June 1999

100VG-AnyLAN


Описание :
100-Mbps Fast Ethernet and Token Ring media technology using four pairs of Category 3, 4, or 5 UTP cabling. This high-speed transport technology, developed by Hewlett-Packard, can operate on existing 10BaseT Ethernet networks. Based on the IEEE 802.12 standard.

Източник: Internetworking Terms and Acronyms, June 1999

1822


Описание :
Historic term that refers to the original ARPANET host-to-IMP interface. The specifications are in BBN report 1822.

Вижте също: IMP

Източник: Internetworking Terms and Acronyms, June 1999

2B1Q


2 binary 1 quaternary
Описание :
Encoding scheme that provides a 2 bits per baud, 80-kbaud per second, 160-kbps transfer rate. The most common signaling method on ISDN U interfaces. This protocol is defined in detail in 1988 ANSI spec T1.601.

Източник: Internetworking Terms and Acronyms, June 1999

802.x


Описание :
Set of IEEE standards for the definition of LAN protocols.

Източник: Internetworking Terms and Acronyms, June 1999

822


Описание :
Short form of RFC 822. Refers to the format of Internet style e-mail as defined in RFC 822.

Източник: Internetworking Terms and Acronyms, June 1999

AAA

Authentication, Authorization, and Accounting


Описание :
Произнася се "тройно А" (triple a)

Източник: Internetworking Terms and Acronyms, June 1999

AAL


ATM Adaptation Layer


Описание :
Service-dependent sublayer of the data link layer. The AAL accepts data from different applications and presents it to the ATM layer in the form of 48-byte ATM payload segments. AALs consist of two sublayers: CS and SAR. AALs differ on the basis of the source-destination timing used, whether they use CBR or VBR, and whether they are used for connection-oriented or connectionless mode data transfer. At present, the four types of AAL recommended by the ITU-T are AAL1, AAL2, AAL3/4, and AAL5.

Вижте също: AAL1, AAL2, AAL3/4, AAL5, ATM, CS, и SAR.

Източник: Internetworking Terms and Acronyms, June 1999

AAL1


ATM Adaptation Layer 1


Описание :
One of four AALs recommended by the ITU-T. AAL1 is used for connection-oriented, delay-sensitive services requiring constant bit rates, such as uncompressed video and other isochronous traffic.

Вижте също: AAL

Източник: Internetworking Terms and Acronyms, June 1999

AAL2


ATM Adaptation Layer 2


Описание :
One of four AALs recommended by the ITU-T. AAL2 is used for connection-oriented services that support a variable bit rate, such as some isochronous video and voice traffic.

Вижте също: AAL

Източник: Internetworking Terms and Acronyms, June 1999

AAL3/4


ATM Adaptation Layer 3/4


Описание :
One of four AALs (merged from two initially distinct adaptation layers) recommended by the ITU-T. AAL3/4 supports both connectionless and connection-oriented links, but is primarily used for the transmission of SMDS packets over ATM networks.

Вижте също: AAL

Източник: Internetworking Terms and Acronyms, June 1999

AAL5


ATM Adaptation Layer 5


Описание :
One of four AALs recommended by the ITU-T. AAL5 supports connection-oriented VBR services and is used predominantly for the transfer of classical IP over ATM and LANE traffic. AAL5 uses SEAL and is the least complex of the current AAL recommendations. It offers low bandwidth overhead and simpler processing requirements in exchange for reduced bandwidth capacity and error-recovery capability.

Вижте също: AAL и SEAL.

Източник: Internetworking Terms and Acronyms, June 1999

AARP


AppleTalk Address Resolution Protocol


Описание :
Protocol in the AppleTalk protocol stack that maps a data-link address to a network address.

Източник: Internetworking Terms and Acronyms, June 1999

ABM


Asynchronous Balanced Mode


Описание :
HDLC (and derivative protocol) communication mode supporting peer-oriented, point-to-point communications between two stations, where either station can initiate transmission.

Източник: Internetworking Terms and Acronyms, June 1999

ABR


1. Available Bit Rate


Описание :
QoS class defined by the ATM Forum for ATM networks. ABR is used for connections that do not require timing relationships between source and destination. ABR provides no guarantees in terms of cell loss or delay, providing only best-effort service. Traffic sources adjust their transmission rate in response to.A 2-3 information they receive describing the status of the network and its capability to successfully deliver data.
Сравнете с: CBR, UBR и VBR.

2. Area Border Router


Описание :
Router located on the border of one or more OSPF areas that connects those areas to the backbone network. ABRs are considered members of both the OSPF backbone and the attached areas. They therefore maintain routing tables describing both the backbone topology and the topology of the other areas.

Източник: Internetworking Terms and Acronyms, June 1999

AC


Alternating Current
Описание :

Английската абривиетура за променлив ток

Вижте също: DC

ACD


Automatic Call Distribution
Описание :
Device or service that automatically reroutes calls to customers in geographically distributed locations served by the same CO

Вижте също: CO

Източник: Internetworking Terms and Acronyms, June 1999

ACELP


Algebraic Code Excited Linear Prediction.

Източник: Internetworking Terms and Acronyms, June 1999

ACF


Advanced Communications Function
Описание :
A group of SNA products that provides distributed processing and resource sharing

Вижте също: ACF/NCP

Източник: Internetworking Terms and Acronyms, June 1999

ACF/NCP


Advanced Communications Function/Network Control Program.
Описание :
The primary SNA NCP. ACF/NCP resides in the communications controller and interfaces with the SNA access method in the host processor to control network communications

Вижте също: ACF и NCP

Източник: Internetworking Terms and Acronyms, June 1999

ACK


ACKnowledgment
Описание :
Notification sent from one network device to another to acknowledge that some event (for example, receipt of a message) occurred.
Сравнете с: NAK

Източник: Internetworking Terms and Acronyms, June 1999

ACML


AMD Core Math Library

ACR


Allowed Cell Rate
Описание :
Parameter defined by the ATM Forum for ATM traffic management. ACR varies between the MCR and the PCR, and is dynamically controlled using congestion control mechanisms.

Вижте също: MCR и PCR

Източник: Internetworking Terms and Acronyms, June 1999

ACSE

Association Control Service Element
Описание :
OSI convention used to establish, maintain, or terminate a connection between two applications.

Източник: Internetworking Terms and Acronyms, June 1999

ActiveX


Описание :
Microsoft’s Windows-specific non-Java technique for writing applets. ActiveX applets take considerably longer to download than the equivalent Java applets; however, they more fully exploit the features of Windows 95. ActiveX is sometimes said to be a superset of Java.

Източник: Internetworking Terms and Acronyms, June 1999

AD

Administrative Domain
Описание :
Group of hosts, routers, and networks operated and managed by a single organization.

Източник: Internetworking Terms and Acronyms, June 1999

ADCCP

Advanced Data Communications Control Protocol
Описание :
ANSI standard bit-oriented data link control protocol.

Източник: Internetworking Terms and Acronyms, June 1999

ADM

Add Drop Multiplexer
Описание :
In OSS, a multiplexer that allows a signal to be added into or dropped out of a SONET span. See also SONET.

Източник: Internetworking Terms and Acronyms, June 1999

ADMD

Administration Management Domain
Описание :
X.400 Message Handling System public carrier. The ADMDs in all countries worldwide together provide the X.400 backbone.

See also PRMD

Източник: Internetworking Terms and Acronyms, June 1999

ADPCM

Adaptive Differential Pulse Code Modulation
Описание :
Process by which analog voice samples are encoded into high-quality digital signals.

Източник: Internetworking Terms and Acronyms, June 1999

ADSL

Asymmetric Digital Subscriber Line
Описание :
One of four DSL technologies. ADSL is designed to deliver more bandwidth downstream (from the central office to the customer site) than upstream. Downstream rates range from 1.5 to 9 Mbps, while upstream bandwidth ranges from 16 to 640 kbps. ADSL transmissions work at distances up to 18,000 feet (5,488 meters) over a single copper twisted pair.

See also HDSL, SDSL, and VDSL

Източник: Internetworking Terms and Acronyms, June 1999

ADSU

ATM DSU
Описание :
Terminal adapter used to access an ATM network via an HSSI-compatible device.

See also DSU

Източник: Internetworking Terms and Acronyms, June 1999

AEP

AppleTalk Echo Protocol
Описание :
Used to test connectivity between two AppleTalk nodes. One node sends a packet to another node and receives a duplicate, or echo, of that packet.

Източник: Internetworking Terms and Acronyms, June 1999

AFI

Authority and Format Identifier
Описание :
Portion of an NSAP-format ATMaddress that identifies the type and format of the IDI portion of an ATM address.

See also IDI and NSAP

Източник: Internetworking Terms and Acronyms, June 1999

AFP

AppleTalk Filing Protocol
Описание :
Presentation-layer protocol that allows users to share data files and application programs that reside on a file server. AFP supports AppleShare and Mac OS File Sharing.

Източник: Internetworking Terms and Acronyms, June 1999

AGP

Accelerated Graphics Port

AIN

Advanced Intelligent Network
Описание :
In SS7, an expanded set of network services made available to the user, and under user control, that requires improvement in network switch architecture, signaling capabilities, and peripherals.

See also SS7

Източник: Internetworking Terms and Acronyms, June 1999

AIO

Asynchronous Input/Output.

Източник: Internetworking Terms and Acronyms, June 1999

AIP

ATM Interface Processor
Описание :
ATM network interface for Cisco 7000 series routers designed to minimize performance bottlenecks at the UNI. The AIP supports AAL3/4 and AAL5.

See also AAL3/4 and AAL5.

Източник: Cisco Systems Terms and Acronyms

AIS

Alarm Indication Signal
Описание :
In a T1 transmission, an all-ones signal transmitted in lieu of the normal signal to maintain transmission continuity and to indicate to the receiving terminal that there is a transmission fault that is located either at, or upstream from, the transmitting terminal.

See also T1

Източник: Internetworking Terms and Acronyms, June 1999

ALU

Arithmetic Logic Unit

Описание :

Mанипулира или обработва данните за всяка инструкция и получава резултат

AM

Amplitude Modulation
Описание :
Modulation technique whereby information is conveyed through the amplitude of the carrier signal.

Compare with FM and PAM

Източник: Internetworking Terms and Acronyms, June 1999

AMA

Automatic Messaging Accounting
Описание :
In OSS, the automatic collection, recording, and processing of information relating to calls for billing purposes.

Източник: Internetworking Terms and Acronyms, June 1999

AMADNS

AMAData Networking System
Описание :
In OSS, the next generation (formerly Bellcore) system for the collection and transport of AMA data from central office switches to a billing system.

See also AMA

Източник: Internetworking Terms and Acronyms, June 1999

AMATPS

AMA Teleprocessing System
Описание :
In OSS, the Bellcore legacy system for collecting and transporting AMA data from central office switches to a billing system. The AMATPS consists of an AMA transmitter and a collector.

See also AMA

Източник: Internetworking Terms and Acronyms, June 1999

AMI

Alternate Mark Inversion
Описание :
Line-code type used on T1 and E1 circuits. In AMI, zeros are represented by 01 during each bit cell, and ones are represented by 11 or 00, alternately, during each bit cell. AMI requires that the sending device maintain ones density. Ones density is not maintained independently of the data stream. Sometimes called binary coded alternate mark inversion.

Compare with B8ZS

Източник: Internetworking Terms and Acronyms, June 1999

ANI

Automatic Number Identification
Описание :
SS7 (signaling system 7) feature in which a series of digits, either analog or digital, are included in the call, identifying the telephone number of the calling device. In other words, ANI identifies the number of the calling party.

Източник: Internetworking Terms and Acronyms, June 1999

ANP

Automatic Numbering Plan.

Източник: Internetworking Terms and Acronyms, June 1999

ANSI

American National Standards Institute
Описание :
Voluntary organization composed of corporate, government, and other members that coordinates standards-related activities, approves U.S. national standards, and develops positions for the United States in international standards organizations. ANSI helps develop international and U.S. standards relating to, among other things, communications and networking. ANSI is a member of the IEC and the ISO.

See also IEC and ISO

Източник: Internetworking Terms and Acronyms, June 1999

AOW

Asia and Oceania Workshop
Описание :
One of the three regional OSI Implementors Workshops.

See also EWOS

Източник: Internetworking Terms and Acronyms, June 1999

APaRT

Automated Packet Recognition/Translation
Описание :
Technology that allows a server to be attached to CDDI or FDDI without requiring the reconfiguration of applications or network protocols. APaRT recognizes specific data link layer encapsulation packet types and, when these packet types are transferred from one medium to another, translates them into the native format of the destination device.

Източник: Cisco Systems Termsand Acronyms

APC

Adjacent Point Code
Описание :
The point code of the next hop in the system for the bearer channels; usually it is the STP (signal transfer point).

Източник: Internetworking Terms and Acronyms, June 1999

API

Application Programming Interface
Описание :
Specification of function-call conventions that defines an interface to a service.

Източник: Internetworking Terms and Acronyms, June 1999

APNIC

Asia Pacific Network Information Center
Описание :
Nonprofit Internet registry organization for the Asia Pacific region. The other Internet registries are currently IANA, RIPE NCC and InterNIC.

Източник: Internetworking Terms and Acronyms, June 1999

APPC

Advanced Program-to-Program Communication
Описание :
IBM SNA system software that allows high-speed communication between programs on different computers in a distributed computing environment. APPC establishes and tears down connections between communicating programs. It consists of two interfaces: programming and data-exchange. The programming interface replies to requests from programs requiring communication; the data-exchange interface establishes sessions between programs. APPC runs on LU 6.2 devices.

See also LU 6.2

Източник: Internetworking Terms and Acronyms, June 1999

APPN

Advanced Peer-to-Peer Networking
Описание :
Enhancement to the original IBM SNA architecture. APPN handles session establishment between peer nodes, dynamic transparent route calculation, and traffic prioritization for APPC traffic.

Compare with APPN+

See also APPC

Източник: Internetworking Terms and Acronyms, June 1999

APPN+


Описание :
Next-generation APPN that replaces the label-swapping routing algorithm with source routing. Also called high-performance routing. See also APPN

Източник: Internetworking Terms and Acronyms, June 1999

APS

automatic protection switching
Описание :
SONET switching mechanism that routes traffic from working lines to protect them in case of a line card failure or fiber cut.

Източник: Internetworking Terms and Acronyms, June 1999

ARA

AppleTalk Remote Access
Описание :
Protocol that provides Macintosh users direct access to information and resources at a remote AppleTalk site.

Източник: Internetworking Terms and Acronyms, June 1999

Archie


Описание :
System that provides lists of anonymous FTP archives. See Gopher, WAIS, and World Wide Web.

Източник: Internetworking Terms and Acronyms, June 1999

ARCnet

Attached Resource Computer Network
Описание :
2.5-Mbps token-bus LAN developed in the late 1970s and early 1980s by Datapoint Corporation.

Източник: Internetworking Terms and Acronyms, June 1999

ARIN

American Registry for Internet Numbers
Описание :
Nonprofit organization established for the purpose of administrating and registrating IP numbers to the geographical areas currently managed by Network Solutions (InterNIC). Those areas include, but are not limited to, North America, South America, South Africa, and the Caribbean.

Източник: Internetworking Terms and Acronyms, June 1999

ARM

Asynchronous Response Mode
Описание :
HDLC communication mode involving one primary station and at least one secondary station, where either the primary or one of the secondary stations can initiate transmissions.

Източник: Internetworking Terms and Acronyms, June 1999

ARP

Address Resolution Protocol
Описание :
Internet protocol used to map an IP address to a MAC address. Defined in RFC 826.

Compare with RARP

Източник: Internetworking Terms and Acronyms, June 1999

ARPA

Advanced Research Projects Agency
Описание :
Research and development organization that is part of DoD. ARPA is responsible for numerous technological advances in communications and networking. ARPA evolved into DARPA, and then back into ARPA again (in 1994).

See also ARPANET, DARPA

Източник: Internetworking Terms and Acronyms, June 1999

ARPANET

Advanced Research Projects Agency Network
Описание :
Landmark packet-switching network established in 1969. ARPANET was developed in the 1970s by BBN and funded by ARPA (and later DARPA). It eventually evolved into the Internet. The term ARPANET was officially retired in 1990.

See also ARPA, BBN, DARPA, and Internet

Източник: Internetworking Terms and Acronyms, June 1999

ARQ

Automatic Repeat Request
Описание :
Communication technique in which the receiving device detects errors and requests retransmissions.

Източник: Internetworking Terms and Acronyms, June 1999

ARU

Alarm Relay Unit.

Източник: Internetworking Terms and Acronyms, June 1999

AS

Autonomous System.

Източник: Internetworking Terms and Acronyms, June 1999

ASAM

ATMsubscriber Access multiplexer
Описание :
A telephone central office multiplexer that supports SDL ports over a wide range of network interfaces. An ASAM sends and receives subscriber data (often Internet services) over existing copper telephone lines, concentrating all traffic onto a single high-speed trunk for transport to the Internet or the enterprise intranet. This device is similar to a DSLAM (different manufacturers use different terms for similar devices).

Източник: Internetworking Terms and Acronyms, June 1999

ASBR

Autonomous System Boundary Router
Описание :
ABR located between an OSPF autonomous system and a non-OSPF network. ASBRs run both OSPF and another routing protocol, such as RIP. ASBRs must reside in a nonstub OSPF area.

See also ABR и OSPF

Източник: Internetworking Terms and Acronyms, June 1999

ASCII

American Standard Code for Information Interchange
Описание :
8-bit code for character representation (7 bits plus parity).

Източник: Internetworking Terms and Acronyms, June 1999

ASCU

Agent-Set Control Unit.

Източник: Internetworking Terms and Acronyms, June 1999

ASI

ATM Service Interface.

Източник: Internetworking Terms and Acronyms, June 1999

ASN

Auxiliary Signal Network.

Източник: Internetworking Terms and Acronyms, June 1999

ASN.1

Abstract Syntax Notation One
Описание :
OSI language for describing data types independent of particular computer structures and representation techniques. Described by ISO International Standard 8824.

See also BER

Източник: Internetworking Terms and Acronyms, June 1999

ASP


1. AppleTalk Session Protocol
Описание :
Protocol that uses ATP to provide session establishment, maintenance, and teardown, as well as request sequencing.

See also ATP

2. [Telecommunications]: Auxiliary Signal Path
Описание :
Link between TransPaths that allows them to exchange signaling information that is incompatible with the PSTN backbone network; used to provide feature transparency.

Източник: Internetworking Terms and Acronyms, June 1999

ASPI

Advanced SCSI Programming Interface

AST

Automatic Spanning Tree
Описание :
Function that supports the automatic resolution of spanning trees in SRB networks, providing a single path for spanning explorer frames to traverse from a given node in the network to another. AST is based on the IEEE 802.1 standard.

See IEEE 802.1 and SRB

Източник: Internetworking Terms and Acronyms, June 1999

ASTA

Advanced Software Technology and Algorithms
Описание :
Component of the HPCC program intended to develop software and algorithms for implementation on high-performance computer and communications systems.

See also HPCC

Източник: Internetworking Terms and Acronyms, June 1999

ATCP

AppleTalk Control Protocol
Описание :
Protocol that establishes and configures AppleTalk over PPP, as defined in RFC 1378.

See also PPP

Източник: Internetworking Terms and Acronyms, June 1999

ATDM

Asynchronous Time-Division Multiplexing
Описание :
Method of sending information that resembles normal TDM, except that time slots are allocated as needed rather than preassigned to specific transmitters.

Compare with FDM и TDM.

Източник: Internetworking Terms and Acronyms, June 1999

ATG

Address Translation Gateway
Описание :
Cisco DECnet routing software function that allows a router to route multiple, independent DECnet networks and to establish a user-specified address translation for selected nodes between networks.

Източник: Cisco Systems Terms and Acronyms

ATH

Attention Hangup.

Източник: Internetworking Terms and Acronyms, June 1999

ATM

Asynchronous Transfer Mode
Описание :
International standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media such as E3, SONET, and T3.

Източник: Internetworking Terms and Acronyms, June 1999

ATMM

ATM Management
Описание :
Process that runs on an ATM switch that controls VCI translation and rate enforcement.

See also ATM and VCD

Източник: Internetworking Terms and Acronyms, June 1999

ATP

AppleTalk Transaction Protocol
Описание :
Transport-level protocol that provides a loss-free transaction service between sockets. The service allows exchanges between two socket clients in which one client requests the other to perform a particular task and to report the results. ATP binds the request and response together to ensure the reliable exchange of request-response pairs.

Източник: Internetworking Terms and Acronyms, June 1999

AU

Access Unit
Описание :
Device that provides ISDN access to PSNs.

See also PSN

Източник: Internetworking Terms and Acronyms, June 1999

AUI

Attachment Unit Interface
Описание :
IEEE 802.3 interface between an MAU and a NIC. The term AUI can also refer to the rear panel port to which an AUI cable might attach. Also called transceiver cable.

See also IEEE 802.3, MAU, and NIC

Източник: Internetworking Terms and Acronyms, June 1999

AUP

Acceptable Use Policy
Описание :
Many transit networks have policies that restrict the use to which the network can be put. Enforcement of AUPs varies with the network.

Източник: Internetworking Terms and Acronyms, June 1999

AURP

AppleTalk Update-Based Routing Protocol
Описание :
Method of encapsulating AppleTalk traffic in the header of a foreign protocol, allowing the connection of two or more discontiguous AppleTalk internetworks through a foreign network (such as TCP/IP) to form an AppleTalk WAN. This connection is called an AURP tunnel. In addition to its encapsulation function, AURP maintains routing tables for the entire AppleTalk WAN by exchanging routing information between exterior routers.

Източник: Internetworking Terms and Acronyms, June 1999

AUSM

ATM User Service Module.

Източник: Internetworking Terms and Acronyms, June 1999

AVM

ATM Voice Multiplexer.

Източник: Internetworking Terms and Acronyms, June 1999

AW

Administrative Weight
Описание :
Value set by the network administrator to indicate the desirability of a network link. One of four link metrics exchanged by PTSPs to determine the available resources of an ATM network.

Източник: Internetworking Terms and Acronyms, June 1999

B8ZS

Binary 8-Zero Ssubstitution
Описание :
Line-code type, used on T1 and E1 circuits, in which a special code is substituted whenever 8 consecutive zeros are sent over the link. This code is then interpreted at the remote end of the connection. This technique guarantees ones density independent of the data stream. Sometimes called bipolar 8-zero substitution.

Compare with AMI

Източник: Internetworking Terms and Acronyms, June 1999

BARRNet

Bay Area Regional Research Network
Описание :
Regional network serving the San Francisco Bay Area. The BARRNet backbone is composed of four University of California campuses (Berkeley, Davis, Santa Cruz, and San Francisco), Stanford University, Lawrence Livermore National Laboratory, and NASA Ames Research Center. BARRNet is now part of BBN Planet.

See also BBN

Източник: Internetworking Terms and Acronyms, June 1999

bash

Bourne-again shell
Описание :
Interactive UNIX shell based on the traditional Bourne shell, but with increased functionality.

Източник: Internetworking Terms and Acronyms, June 1999

BBN

Bolt, Beranek, and Newman, Inc
Описание :
High-technology company located in Massachusetts that developed and maintained the ARPANET (and later, the Internet) core gateway system.

Източник: Internetworking Terms and Acronyms, June 1999


Източник:

BBS

Bulletin Board System

Bc

Committed Burst
Описание :
Negotiated tariff metric in Frame Relay internetworks. The maximum amount of data (in bits) that a Frame Relay internetwork is committed to accept and transmit at the CIR.

See also Be and CIR

Източник: Internetworking Terms and Acronyms, June 1999

BCP

Best Current Practices
Описание :
The newest subseries of RFCs that are written to describe BCPs in the Internet. Rather than specifying a protocol, these documents specify the best ways to use the protocols and the best ways to configure options to ensure interoperability between various vendors’ products.

Източник: Internetworking Terms and Acronyms, June 1999

BDCS

Broadband Digital Cross-Connect System
Описание :
SONET DCS capable of cross-connecting DS-3, STS-1 and STS-3c signals.

See also DCS

Източник: Internetworking Terms and Acronyms, June 1999

BECN

Backward Explicit Congestion Notification
Описание :
Bit set by a Frame Relay network in frames traveling in the opposite direction of frames encountering a congested path. DTE receiving frames with the BECN bit set can request that higher-level protocols take flow control action as appropriate.

Compare with FE

Източник: Internetworking Terms and Acronyms, June 1999

BER

1. bit error rate. Ratio of received bits that contain errors. 2. basic encoding rules. Rules for encoding data units described in the ISO ASN.1 standard. See also ASN.1.

Източник: Internetworking Terms and Acronyms, June 1999

BERT

Bit Error Rate Tester
Описание :
Device that determines the BER on a given communications channel.

See also BER

Източник: Internetworking Terms and Acronyms, June 1999

BGP

Border Gateway Protocol
Описание :
Interdomain routing protocol that replaces EGP. BGP exchanges reachability information with other BGP systems. It is defined by RFC 1163.

See also BGP4 and EGP

Източник: Internetworking Terms and Acronyms, June 1999

BGP4

BGP Version 4
Описание :
Version 4 of the predominant interdomain routing protocol used on the Internet. BGP4 supports CIDR and uses route aggregation mechanisms to reduce the size of routing tables.

See also BGP and CIDR

Източник: Internetworking Terms and Acronyms, June 1999

BIA

burned-in MAC address.

Източник: Internetworking Terms and Acronyms, June 1999

BICI

Broadband Inter-Carrier Interface
Описание :
ITU-T standard that defines the protocols and procedures needed for establishing, maintaining, and terminating broadband switched virtual connections between public networks.

Източник: Internetworking Terms and Acronyms, June 1999

BIGA

Bus Interface Gate Array
Описание :
Technology that allows the Catalyst 5000 to receive and transmit frames from its packet-switching memory to its MAC local buffer memory without the intervention of the host processor. Cisco Systems Terms and Acronyms

BIND

Berkeley Internet Name Domain Implementation of DNS developed and distributed by the University of California at Berkeley (United States). Many Internet hosts run BIND, which is the ancestor of many commercial BIND implementations.

Източник: Internetworking Terms and Acronyms, June 1999

BinHex

Binary Hexadecimal
Описание :
Method for converting binary files into ASCII for transmission by applications, such as e-mail, that can only handle ASCII.

Източник: Internetworking Terms and Acronyms, June 1999

BIOS

Basic Input/Output System

BIP

bit interleaved parity
Описание :
In ATM, a method used to monitor errors on a link. A check bit or word is sent in the link overhead for the previous block or frame. Bit errors in the payload can then be detected and reported as maintenance information.

Източник: Internetworking Terms and Acronyms, June 1999

BISDN

Broadband ISDN
Описание :
ITU-T communication standards designed to handle high-bandwidth applications such as video. BISDN currently uses ATMtechnology over SONET-based transmission circuits to provide data rates from 155 to 622 Mbps and beyond. Contrast with N-ISDN. See also BRI, ISDN, and PRI

Източник: Internetworking Terms and Acronyms, June 1999

bisync

Binary Synchronous Communication Protocol
Описание :
Character-oriented data-link protocol for applications. Contrast with Synchronous Data Link Control (SDLC).

Източник: Internetworking Terms and Acronyms, June 1999

bit

Binary digit used in the binary numbering system. Can be 0 or 1.

Източник: Internetworking Terms and Acronyms, June 1999

BITNET

“Because It’s Time” Networking Services
Описание :
Low-cost, low-speed academic network consisting primarily of IBM mainframes and 9600-bps leased lines. BITNET is now part of CREN. See also CREN.

Източник: Internetworking Terms and Acronyms, June 1999

BLSR

Bidirectional Line Switch Ring
Описание :
SONET ring architecture that provides working and protection fibers between nodes. If the working fiber between nodes is cut, traffic is automatically routed onto the protection fiber. See also SONET

Източник: Internetworking Terms and Acronyms, June 1999

BNC


Описание :
Standard connector used to connect IEEE 802.3 10Base2 coaxial cable to an MAU.

Източник: Internetworking Terms and Acronyms, June 1999

BNI

Broadband Network Interface.

Източник: Internetworking Terms and Acronyms, June 1999

BNM

Broadband Network Module.

Източник: Internetworking Terms and Acronyms, June 1999

BNN

boundary network node
Описание :
In SNA terminology, a subarea node that provides boundary function support for adjacent peripheral nodes. This support includes sequencing, pacing, and address translation. Also called boundary node.

Източник: Internetworking Terms and Acronyms, June 1999

BOBI

break-out/break-in
Описание :
VNS feature that allows interworking between Euro-ISDN (ETSI) and other VNS-supported signaling variants, such as DPNSS and QSIG.

Източник: Internetworking Terms and Acronyms, June 1999

BOC

Bell operating company
Описание :
Twenty-two local phone companies formed by the breakup of AT&T. See RBOC

Източник: Internetworking Terms and Acronyms, June 1999

BOOTP

Bootstrap Protocol
Описание :
Protocol used by a network node to determine the IP address of its Ethernet interfaces, in order to affect network booting.

Източник: Internetworking Terms and Acronyms, June 1999

BPDU

Bridge Protocol Data Unit
Описание :
Spanning-Tree Protocol hello packet that is sent out at configurable intervals to exchange information among bridges in the network. See also PDU.

Източник: Internetworking Terms and Acronyms, June 1999

BPI

baseline privacy interface.

Източник: Internetworking Terms and Acronyms, June 1999

bps

bits per second.

Източник: Internetworking Terms and Acronyms, June 1999

BPV

bipolar violation.

Източник: Internetworking Terms and Acronyms, June 1999

BRHR

Basic Research and Human Resources
Описание :
Component of the HPCC program designed to support research, training, and education in computer science, computer engineering, and computational science. See also HPCC

Източник: Internetworking Terms and Acronyms, June 1999

BRF

bridge relay function.

Източник: Internetworking Terms and Acronyms, June 1999

BRI

Basic Rate Interface
Описание :
ISDN interface composed of two B channels and one D channel for circuit-switched communication of voice, video, and data. Compare with PRI. See also BISDN, ISDN, and N-ISDN

Източник: Internetworking Terms and Acronyms, June 1999

BSC

binary synchronous communication
Описание :
Character-oriented data link layer protocol for half-duplex applications. A form of telecommunication line control that uses a standard set of transmission control characters and control character sequences, for binary synchronous transmission of binary-coded data between stations. Often referred to simply as .

Източник: Internetworking Terms and Acronyms, June 1999

BSD

Berkeley Standard Distribution
Описание :
Term used to describe any of a variety of UNIX-type operating systems based on the UC Berkeley BSD operating system.

Източник: Internetworking Terms and Acronyms, June 1999

BSTUN

Block Serial Tunneling

Източник: Internetworking Terms and Acronyms, June 1999

BT

burst tolerance
Описание :
Parameter defined by the ATMForum for ATMtraffic management. For VBR connections, BT determines the size of the maximum burst of contiguous cells that can be transmitted. See also VBR

Източник: Internetworking Terms and Acronyms, June 1999

BTU

British thermal units.

Източник: Internetworking Terms and Acronyms, June 1999

BTW

by the way
Описание :
One of many short-hand phrases used in chat sessions and e-mail conversations. See also IMHO

Източник: Internetworking Terms and Acronyms, June 1999

BUS

broadcast and unknown server
Описание :
Multicast server used in ELANs that is used to flood traffic addressed to an unknown destination and to forward multicast and broadcast traffic to the appropriate clients. See also ELAN

Източник: Internetworking Terms and Acronyms, June 1999

BVI

Bridge Group Virtual Interface

Източник: Internetworking Terms and Acronyms, June 1999

BX.25

AT&T implementation of X.25. See also X.25.

BXM

Broadband Switch Module.

Източник: Internetworking Terms and Acronyms, June 1999

byte


Описание :
Term used to refer to a series of consecutive binary digits that are operated upon as a unit (for example, an 8-bit byte).

Източник: Internetworking Terms and Acronyms, June 1999

CA

1. certification authority. 2. Telecommunications: call appearance.

Източник: Internetworking Terms and Acronyms, June 1999

CAC

connection admission control
Описание :
Set of actions taken by each ATM switch during connection setup in order to determine whether a connection’s requested QoS will violate the QoS guarantees for established connections. CAC is also used when routing a connection request through an ATM network.

Източник: Internetworking Terms and Acronyms, June 1999

CAF

controllable ATM fabric.

Източник: Internetworking Terms and Acronyms, June 1999

CAM

1.Content-Addressable Memory

Източник: Internetworking Terms and Acronyms, June 1999

2.Cisco Access Manager.

Източник: Cisco Systems Terms and Acronyms

3. Common Access Method

Източник: A+ Certification Training Kit

CAP

Competitive Access Provider
Описание :
Independent company providing local telecommunications services mainly to business customers in competition with an area’s BOC or IOC. Teleport and MFS are the two major CAPs operating in major metropolitan areas in the United States. See also BOC and IOC

Източник: Internetworking Terms and Acronyms, June 1999

CAS


Collon Address Select

CATV

cable television
Описание :
Communication system where multiple channels of programming material are transmitted to homes using broadband coaxial cable. Formerly called Community Antenna Television.

Източник: Internetworking Terms and Acronyms, June 1999

CBAC

Context-based Access Control
Описание :
Protocol that provides internal users with secure access control for each application and for all traffic across network perimeters. CBAC enhances security by scrutinizing both source and destination addresses and by tracking each application’s connection status.

Източник: Internetworking Terms and Acronyms, June 1999

CBDS

Connectionless Broadband Data Service
Описание :
European high-speed, packet-switched, datagram-based WAN networking technology. Similar to SMDS. See also SMDS

Източник: Internetworking Terms and Acronyms, June 1999

CBR

constant bit rate
Описание :
QoS class defined by the ATMForum for ATMnetworks. CBR is used for connections that depend on precise clocking to ensure undistorted delivery. Compare with ABR, UBR, and VBR.

Източник: Internetworking Terms and Acronyms, June 1999

CCB

call control block.

Източник: Internetworking Terms and Acronyms, June 1999

CCITT

Consultative Committee for International Telegraph and Telephone International
Описание :
organization responsible for the development of communications standards. Now called the ITU-T. See ITU-T.

Източник: Internetworking Terms and Acronyms, June 1999

CCOT

cross office transfer time.

Източник: Internetworking Terms and Acronyms, June 1999

CCR

commitment, concurrency, and recovery
Описание :
OSI application service element used to create atomic operations across distributed systems. Used primarily to implement two-phase commit for transactions and nonstop operations.

Източник: Internetworking Terms and Acronyms, June 1999

CCS

common channel signaling
Описание :
Signaling system used in telephone networks that separates signaling information from user data. A specified channel is exclusively designated to carry signaling information for all other channels in the system. See also SS7

Източник: Internetworking Terms and Acronyms, June 1999

CD

Carrier Detect
Описание :
Signal that indicates whether an interface is active. Also, a signal generated by a modem indicating that a call has been connected.

Източник: Internetworking Terms and Acronyms, June 1999

CDDI

Copper Distributed Data Interface
Описание :
Implementation of FDDI protocols over STP and UTP cabling. CDDI transmits over relatively short distances (about 90 yards [100 meters]), providing data rates of 100 Mbps using a dual-ring architecture to provide redundancy. Based on the ANSI TPPMD standard. Compare with FDDI

Източник: Internetworking Terms and Acronyms, June 1999

CDF

channel definition format
Описание :
Technology for “push” applications on the World Wide Web. CDF is an application of XML. See XML

Източник: Internetworking Terms and Acronyms, June 1999

CDP

Cisco Discovery Protocol
Описание :
Media- and protocol-independent device-discovery protocol that runs on all Cisco-manufactured equipment including routers, access servers, bridges, and switches. Using CDP, a device can advertise its existence to other devices and receive information about other devices on the same LAN or on the remote side of a WAN. Runs on all media that support SNAP, including LANs, Frame Relay, and ATM media. Cisco Systems Terms and Acronyms.

CDPD

Cellular Digital Packet Data
Описание :
Open standard for two-way wireless data communication over high-frequency cellular telephone channels. Allows data transmissions between a remote cellular link and a NAP. Operates at 19.2 Kbps.

Източник: Internetworking Terms and Acronyms, June 1999

CDR

Call Detail Record
Описание :
VNS record of voice or data SVCs, which includes calling and called numbers, local and remote node names, data and timestamp, elapsed time, and Call Failure Class fields.

Източник: Cisco Systems Terms and Acronyms

CDROM

Compact Disc Read-Only Memory

Източник: A+ Certification Training Kit

CDV

cell delay variation
Описание :
Component of cell transfer delay, which is induced by buffering and cell scheduling. CDV is a QoS delay parameter associated with CBR and VBR service. See also CBR and VBR

Източник: Internetworking Terms and Acronyms, June 1999

CDVT

cell delay variation tolerance
Описание :
In ATM, a QoS parameter for managing traffic that is specified when a connection is set up. In CBR transmissions, CDVT determines the level of jitter that is tolerable for the data samples taken by the PCR. See also CBR and PCR

Източник: Internetworking Terms and Acronyms, June 1999

CEF

Cisco express forwarding. Cisco Systems Terms and Acronyms

CELP

code excited linear prediction compression
Описание :
Compression algorithm used in low bit-rate voice encoding. Used in ITU-T Recommendations G.728, G.729, G.723.1.

Източник: Internetworking Terms and Acronyms, June 1999

CEPT

Confйrence Europйenne des Postes et des Tйlйcommunications
Описание :
Association of the 26 European PTTs that recommends communication specifications to the ITU-T.

Източник: Internetworking Terms and Acronyms, June 1999

CER

cell error ratio
Описание :
In ATM, the ratio of transmitted cells that have errors to the total cells sent in a transmission for a specific period of time.

Източник: Internetworking Terms and Acronyms, June 1999

CERFnet

California Education and Research Federation Network
Описание :
TCP/IP network, based in Southern California, that connects hundreds of higher-education centers internationally while also providing Internet access to subscribers. CERFnet was founded in 1988 by the San Diego Supercomputer Center and General Atomics, and is funded by the NSF.

Източник: Internetworking Terms and Acronyms, June 1999

CERN

European Laboratory for Particle Physics
Описание :
Birthplace of the World Wide Web.

Източник: Internetworking Terms and Acronyms, June 1999

CERT

Computer Emergency Response Team
Описание :
Chartered to work with the Internet community to facilitate its response to computer security events involving Internet hosts, to take proactive steps to raise the community’s awareness of computer security issues, and to conduct research targeted at improving the security of existing systems. The U.S. CERT is based at Carnegie Mellon University in Pittsburgh (United States), Regional CERTs are, like NICs, springing up in different parts of the world.

Източник: Internetworking Terms and Acronyms, June 1999

CES

circuit emulation service
Описание :
Enables users to multiplex or concentrate multiple circuit emulation streams for voice and video with packet data on a single high-speed ATMlink without a separate ATM access multiplexer.

Източник: Internetworking Terms and Acronyms, June 1999

CFRAD

Cisco Frame Relay access device
Описание :
Cisco product that supports Cisco IOS Frame Relay SNA services and can be upgraded to be a full-function multiprotocol router. The Cisco FRAD connects SDLC devices to Frame Relay without requiring an existing LAN. However, the Cisco FRAD does support attached LANs and can perform conversion from SDLC to Ethernet and Token Ring. See also FRAD

Източник: Cisco Systems Terms and Acronyms

CGA

Color/Graphics Adapter

Източник: A+ Certification Training Kit

CGI

Common Gateway Interface
Описание :
Set of rules that describe how a Web server communicates with another application running on the same computer and how the application (called a CGI program) communicates with the Web server. Any application can be a CGI program if it handles input and output according to the CGI standard.

Източник: Internetworking Terms and Acronyms, June 1999

CHAP

Challenge Handshake Authentication Protocol
Описание :
Security feature supported on lines using PPP encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, it merely identifies the remote end. The router or access server then determines whether that user is allowed access. Compare to PAP

Източник: Internetworking Terms and Acronyms, June 1999

CHS

Cylinder Head Sector

Източник: A+ Certification Training Kit

CIA

classical IP over ATM
Описание :
Specification for running IP over ATM in a manner that takes full advantage of the features of ATM. Defined in RFC 1577.

Източник: Internetworking Terms and Acronyms, June 1999

CICNet

Regional network that connects academic, research, nonprofit, and commercial organizations in the Midwestern United States. Founded in 1988, CICNet was a part of the NSFNET and was funded by the NSF until the NSFNET dissolved in 1995. See also NSFNET.

Източник: Internetworking Terms and Acronyms, June 1999

CICS

Customer Information Control System
Описание :
IBM application subsystem allowing transactions entered at remote terminals to be processed concurrently by user applications.

Източник: Internetworking Terms and Acronyms, June 1999

CID

1. craft interface device. Terminal or PC-based interface that enables the performance of local maintenance operations. 2. channel ID. Designates the Frame Relay subchannel ID for Voice over Frame Relay.

CIDR

classless interdomain routing
Описание :
Technique supported by BGP4 and based on route aggregation. CIDR allows routers to group routes together in order to cut down on the quantity of routing information carried by the core routers. With CIDR, several IP networks appear to networks outside the group as a single, larger entity. With CIDR, IP addresses and their subnet masks are written as 4 octets, separated by periods, followed by a forward slash and a 2-digit number that represents the subnet mask. See also BGP4

Източник: Internetworking Terms and Acronyms, June 1999

CIP

Channel Interface Processor
Описание :
Channel attachment interface for Cisco 7000 series routers. The CIP is used to connect a host mainframe to a control unit, eliminating the need for an FEP for channel attachment. Cisco Systems Terms and Acronyms.

CIR

committed information rate
Описание :
Rate at which a Frame Relay network agrees to transfer information under normal conditions, averaged over a minimum increment of time. CIR, measured in bits per second, is one of the key negotiated tariff metrics. See also Bc

Източник: Internetworking Terms and Acronyms, June 1999

CISC

Complex Instruction Set Computing

CIX

Commercial Internet Exchange
Описание :
A connection point between the commercial Internet service providers. Pronounced “kicks.” See FIX and GIX

Източник: Internetworking Terms and Acronyms, June 1999

CLAW

Common Link Access for Workstations
Описание :
Data link layer protocol used by channel-attached RISC System/6000 series systems and by IBM 3172 devices running TCP/IP off-load. CLAW improves efficiency of channel use and allows the CIP to provide the functionality of a 3172 in TCP/IP environments and support direct channel attachment. The output from TCP/IP mainframe processing is a series of IP datagrams that the router can switch without modifications.

Източник: Internetworking Terms and Acronyms, June 1999

CLEC

competitive local exchange carrier
Описание :
Company that builds and operates communication networks in metropolitan areas and provides its customers with an alternative to the local telephone company. See CAP

Източник: Internetworking Terms and Acronyms, June 1999

CLI


1. command line interface Interface that allows the user to interact with the operating system by entering commands and optional arguments. The UNIX operating system and DOS provide CLIs. Compare with GUI. 2. Command Language Interpreter Basic Cisco IOS configuration and management interface.

CLNP

Connectionless Network Protocol
Описание :
OSI network layer protocol that does not require a circuit to be established before data is transmitted. See also CLNS

Източник: Internetworking Terms and Acronyms, June 1999

CLNS

Connectionless Network Service
Описание :
OSI network layer service that does not require a circuit to be established before data is transmitted. CLNS routes messages to their destinations independently of any other messages. See also CLNP

Източник: Internetworking Terms and Acronyms, June 1999

CLP

cell loss priority
Описание :
Field in the ATM cell header that determines the probability of a cell being dropped if the network becomes congested. Cells with CLP = 0 are insured traffic, which is unlikely to be dropped. Cells with CLP = 1 are best-effort traffic, which might be dropped in congested conditions in order to free up resources to handle insured traffic.

Източник: Internetworking Terms and Acronyms, June 1999

CLR

cell loss ratio
Описание :
In ATM, the ratio of discarded cells to cells that are successfully transmitted. CLR can be set as a QoS parameter when a connection is set up.

Източник: Internetworking Terms and Acronyms, June 1999

CLS

Cisco link services
Описание :
A front-end for a variety of data-link control services. Cisco Systems Terms and Acronyms.

CLSI

Cisco Link Services Interface
Описание :
Messages that are exchanged between CLS and data-link users such as APPN, SNA service point, and DLSw+. Cisco Systems Terms and Acronyms.

CLTP

Connectionless Transport Protocol
Описание :
Provides for end-to-end Transport data addressing (via Transport selector) and error control (via checksum), but cannot guarantee delivery or provide flow control. The OSI equivalent of UDP.

CMI

1. coded mark inversion. ITU-T line coding technique specified for STS-3c transmissions. Also used in DS-1 systems. See also DS-1 and STS-3c. 2. control mode idle?

Източник: Internetworking Terms and Acronyms, June 1999

CMIP

Common Management Information Protocol
Описание :
OSI network management protocol created and standardized by ISO for the monitoring and control of heterogeneous networks. See also CMIS

Източник: Internetworking Terms and Acronyms, June 1999

CMIS

Common Management Information Services
Описание :
OSI network management service interface created and standardized by ISO for the monitoring and control of heterogeneous networks. See also CMIP

Източник: Internetworking Terms and Acronyms, June 1999

CMNS

Connection-Mode Network Service
Описание :
Extends local X.25 switching to a variety of media (Ethernet, FDDI, Token Ring). See also CONP

Източник: Internetworking Terms and Acronyms, June 1999

CMOS

Complementary Metal-Oxide Semiconductor

Източник: A+ Certification Training Kit

CMT

connection management
Описание :
FDDI process that handles the transition of the ring through its various states (off, active, connect, and so on), as defined by the ANSI X3T9.5 specification.

Източник: Internetworking Terms and Acronyms, June 1999

CMTS

cable modem termination system
Описание :
Any DOCSIS-compliant headend cable router, such as the Cisco uBR7246.

Източник: Internetworking Terms and Acronyms, June 1999

CO

central office
Описание :
Local telephone company office to which all local loops in a given area connect and in which circuit switching of subscriber lines occurs.

Източник: Internetworking Terms and Acronyms, June 1999

codec

coder-decoder
Описание :
1. Integrated circuit device that typically uses pulse code modulation to transform analog signals into a digital bit stream and digital signals back into analog signals. 2. In Voice over IP, Voice over Frame Relay, and Voice over ATM, a DSP software algorithm used to compress/decompress speech or audio signals.

Източник: Internetworking Terms and Acronyms, June 1999

COM

Serial Communications Port

Източник: A+ Certification Training Kit

CONF

configuration failure
Описание :
Resource is OOS because its provisioning information is inconsistent.

Източник: Internetworking Terms and Acronyms, June 1999

CONP

Connection-Oriented Network Protocol
Описание :
OSI protocol providing connection-oriented operation to upper-layer protocols. See also CMNS

Източник: Internetworking Terms and Acronyms, June 1999

CONS

connection-oriented network service.

Източник: Internetworking Terms and Acronyms, June 1999

console

DTE through which commands are entered into a host.

Източник: Internetworking Terms and Acronyms, June 1999

cookie


Описание :
Piece of information sent by a Web server to a Web browser that the browser is expected to save and send back to the Web server whenever the browser makes additional requests of the Web server.

Източник: Internetworking Terms and Acronyms, June 1999

COOS

Commanded OOS
Описание :
A resource is OOS because it was entered as a command. See also OOS in the “Cisco Systems Terms and Acronyms” section.

Източник: Internetworking Terms and Acronyms, June 1999

COPS

Common Open Policy Service
Описание :
Quality-of-service (QoS) policy exchange protocol proposed as an IETF standard for communicating network QoS policy information.

Източник: Internetworking Terms and Acronyms, June 1999

CORBA

Common Object Request Broker Architecture
Описание :
OMG’s answer to the need for interoperability among the rapidly proliferating number of hardware and software products available today. Simply stated, CORBA allows applications to communicate with one another no matter where they are located or who has designed them. See IIOP

Източник: Internetworking Terms and Acronyms, June 1999

CoS

class of service
Описание :
Indication of how an upper-layer protocol requires a lower-layer protocol to treat its messages. In SNA subarea routing, COS definitions are used by subarea nodes to determine the optimal route to establish a given session. A COS definition comprises a virtual route number and a transmission priority field. Also called ToS.

Източник: Internetworking Terms and Acronyms, June 1999

COS

Corporation for Open Systems
Описание :
Organization that promulgates the use of OSI protocols through conformance testing, certification, and related activities.

Източник: Internetworking Terms and Acronyms, June 1999

COSINE

Cooperation for Open Systems Interconnection Networking in Europe
Описание :
European project financed by the EC to build a communication network between scientific and industrial entities in Europe. The project ended in 1994.

Източник: Internetworking Terms and Acronyms, June 1999

COT

Continuity Test
Описание :
Requirement of the SS7 protocol specifications. It tests the bearer channels’ status using either loopback or tone detection and generation. Used to test individual DS0 channels via either loopback or tone detection and generation.

Източник: Internetworking Terms and Acronyms, June 1999

CP

1. control point. In SNA networks, element that identifies the APPN networking components of a PU 2.1 node, manages device resources, and provides services to other devices. In APPN, CPs are able to communicate with logically adjacent CPs by way of CP-to-CP sessions. See also EN and NN. 2. Telecommunications: control processor.

Източник: Internetworking Terms and Acronyms, June 1999

CPC

calling party category.

Източник: Internetworking Terms and Acronyms, June 1999

CPCS

1. common part convergence sublayer. One of the two sublayers of any AAL. The CPCS is service-independent and is further divided into the CS and the SAR sublayers. The CPCS is responsible for preparing data for transport across the ATMnetwork, including the creation of the 48-byte payload cells that are passed to the ATMlayer. See also AAL, ATM layer, CS, SAR, and SSCS. 2. Telecommunications: call processing control system.

Източник: Internetworking Terms and Acronyms, June 1999

CPE

customer premises equipment
Описание :
Terminating equipment, such as terminals, telephones, and modems, supplied by the telephone company, installed at customer sites, and connected to the telephone company network.

Източник: Internetworking Terms and Acronyms, June 1999

CPI-C

common programming interface for communications
Описание :
Platform-independent API developed by IBM and used to provide portability in APPC applications. See also APPC.

Източник: Internetworking Terms and Acronyms, June 1999

CPNIE

called party number information element.

Източник: Internetworking Terms and Acronyms, June 1999

CPP

Combinet Proprietary Protocol

Източник: Cisco Systems Terms and Acronyms.

cps

cells per second.

Източник: Internetworking Terms and Acronyms, June 1999

CPU

Central Processing Unit

CQ

custom queuing

Източник: Internetworking Terms and Acronyms, June 1999

CRC

cyclic redundancy check
Описание :
Error-checking technique in which the frame recipient calculates a remainder by dividing frame contents by a prime binary divisor and compares the calculated remainder to a value stored in the frame by the sending node.

Източник: Internetworking Terms and Acronyms, June 1999

CREN

Corporation for Research and Educational Networking
Описание :
The result of a merger of BITNET and CSNET. CREN is devoted to providing Internet connectivity to its members, which include the alumni, students, faculty, and other affiliates of participating educational and research institutions, via BITNET III. See also BITNET, BITNET III, and CSNET

Източник: Internetworking Terms and Acronyms, June 1999

CRF

Concentrator Relay Function CRMcell rate margin. One of three link attributes exchanged using PTSPs to determine the available resources of an ATMnetwork. CRM is a measure of the difference between the effective bandwidth allocation per traffic class as the allocation for sustainable cell rate.

Източник: Internetworking Terms and Acronyms, June 1999

CRL

certificate revocation list.

Източник: Internetworking Terms and Acronyms, June 1999

CRT

Cathode-Ray Tube

Източник: A+ Certification Training Kit

CRV

call reference value
Описание :
Number carried in all Q.931 (I.451) messages that provides an identifier for each ISDN call.

Източник: Internetworking Terms and Acronyms, June 1999

CS

convergence sublayer
Описание :
One of the two sublayers of the AAL CPCS, which is responsible for padding and error checking. PDUs passed from the SSCS are appended with an 8-byte trailer (for error checking and other control information) and padded, if. necessary, so that the length of the resulting PDU is divisible by 48. These PDUs are then passed to the SAR sublayer of the CPCS for further processing. See also AAL,CPCS, SAR, and SSCS

Източник: Internetworking Terms and Acronyms, June 1999

CSA

Canadian Standards Association
Описание :
Canadian agency that certifies products that conform to Canadian national safety standards.

Източник: Internetworking Terms and Acronyms, June 1999

CS-ACELP

Conjugate Structure Algebraic Code Excited Linear Prediction
Описание :
CELP voice compression algorithm providing 8 Kbps, or 8:1 compression, standardized in ITU-T Recommendation G.729.

Източник: Internetworking Terms and Acronyms, June 1999

CSI

called subscriber identification
Описание :
An identifier whose coding format contains the telephone number from a remote fax terminal.

Източник: Internetworking Terms and Acronyms, June 1999

CSLIP

Compressed Serial Link Internet Protocol
Описание :
Extension of SLIP that, when appropriate, allows just header information to be sent across a SLIP connection, reducing overhead and increasing packet throughput on SLIP lines. See also SLIP

Източник: Internetworking Terms and Acronyms, June 1999

CSM

call switching module.

Източник: Internetworking Terms and Acronyms, June 1999

CSMA/CD

carrier sense multiple access collision detect
Описание :
Media-access mechanism wherein devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. If two devices transmit at once, a collision occurs and is detected by all colliding devices. This collision subsequently delays retransmissions from those devices for some random length of time. CSMA/CD access is used by Ethernet and IEEE 802.3.

Източник: Internetworking Terms and Acronyms, June 1999

CSNET

Computer Science Network
Описание :
Large internetwork consisting primarily of universities, research institutions, and commercial concerns. CSNET merged with BITNET to form CREN. See also BITNET and CREN

Източник: Internetworking Terms and Acronyms, June 1999

CSNP

complete sequence number PDU
Описание :
PDU sent by the designated router in an OSPF network to maintain database synchronization.

Източник: Internetworking Terms and Acronyms, June 1999

CSU

channel service unit
Описание :
Digital interface device that connects end-user equipment to the local digital telephone loop. Often referred to together with DSU, as CSU/DSU. See also DSU.

Източник: Internetworking Terms and Acronyms, June 1999

CTD

cell transfer delay
Описание :
In ATM, the elapsed time between a cell exit event at the source UNI and the corresponding cell entry event at the destination UNI for a particular connection. The CTD between the two points is the sum of the total inter-ATM node transmission delay and the total ATM node processing delay.

Източник: Internetworking Terms and Acronyms, June 1999

CTI

computer telephony integration
Описание :
Name given to the merger of traditional telecommunications (PBX) equipment with computers and computer applications. The use of Caller ID to automatically retrieve customer information from a database is an example of a CTI application.

Източник: Internetworking Terms and Acronyms, June 1999

CTS

1. Clear To Send. Circuit in the EIA/TIA-232 specification that is activated when DCE is ready to accept data from a DTE. 2. common transport semantic. Cornerstone of the IBM strategy to reduce the number of protocols on networks. CTS provides a single API for developers of network software and enables applications to run over APPN, OSI, and TCP/IP.

Източник: Internetworking Terms and Acronyms, June 1999

CU

coding unit
Описание :
Type of access device. (See access device.)

Източник: Internetworking Terms and Acronyms, June 1999

CUPS

Common UNIX Printing System
Описание :
www.cups.org

CxBus

Cisco Extended Bus
Описание :
Data bus for interface processors on Cisco 7000 series routers. See also SP. Cisco Systems Terms and Acronyms.

Cyberspace


Описание :
Term coined by William Gibson in his fantasy novel Neuromancer to describe the “world” of computers and the society that gathers around them. Often used to refer to the Internet, the World Wide Web, or some combination thereof.

Източник: Internetworking Terms and Acronyms, June 1999

DAC

dual-attached concentrator
Описание :
FDDI or CDDI concentrator capable of attaching to both rings of an FDDI or CDDI network. It can also be dual-homed from the master ports of other FDDI or CDDI concentrators.

Източник: Internetworking Terms and Acronyms, June 1999

DACS

Digital Access and Crossconnect System
Описание :
AT&T’s term for a digital crossconnect system.

Източник: Internetworking Terms and Acronyms, June 1999

DAP

Directory Access Protocol
Описание :
Protocol used between a DUA and a DSA in an X.500 directory system. See LDAP

Източник: Internetworking Terms and Acronyms, June 1999

DARPA

Defense Advanced Research Projects Agency
Описание :
U.S. government agency that funded research for and experimentation with the Internet. Evolved from ARPA, and then, in 1994, back to ARPA. See also ARPA

Източник: Internetworking Terms and Acronyms, June 1999

DAS

1. dual attachment station. Device attached to both the primary and the secondary FDDI rings. Dual attachment provides redundancy for the FDDI ring: if the primary ring fails, the station can wrap the primary ring to the secondary ring, isolating the failure and retaining ring integrity. Also called a Class A station. Compare with SAS. 2. dynamically assigned socket. Socket that is dynamically assigned by DDP upon request by a client. In an AppleTalk network, the sockets numbered 128 to 254 are allocated as DASs.

Източник: Internetworking Terms and Acronyms, June 1999

dB

decibels

Източник: Internetworking Terms and Acronyms, June 1999

DB2

IBM relational database management system

Източник: Internetworking Terms and Acronyms, June 1999

dBm

decibles per milliwatt

Източник: Internetworking Terms and Acronyms, June 1999

DC

Direct Current
Описание :

Английското название за постоянен ток

Вижте също : AC

Източник: A+ Certification Training Kit

DCA

Defense Communications Agency
Описание :
U.S. government organization responsible for DDN networks such as MILNET. Now called DISA. See DISA.

Източник: Internetworking Terms and Acronyms, June 1999

DCC

Data Country Code
Описание :
One of two ATM address formats developed by the ATM Forum for use by private networks. Adapted from the subnetwork model of addressing in which the ATM layer is responsible for mapping network layer addresses to ATM addresses. Compare with ICD.

Източник: Internetworking Terms and Acronyms, June 1999

DCE

1. data communications equipment (EIA expansion). 2. data circuit-terminating equipment (ITU-T expansion). Devices and connections of a communications network that comprise the network end of the user-to-network interface. The DCE provides a physical connection to the network, forwards traffic, and provides a clocking signal used to synchronize data transmission between DCE and DTE devices. Modems and interface cards are examples of DCE. Compare with DTE

Източник: Internetworking Terms and Acronyms, June 1999

DCOM

Distributed Component Object Model
Описание :
Protocol that enables software components to communicate directly over a network. Developed by Microsoft and previously called Network OLE, DCOMis designed for use across multiple network transports, including Internet protocols such as HTTP. See IIOP

Източник: Internetworking Terms and Acronyms, June 1999

DCS

Digital Crossconnect System
Описание :
Network element providing automatic cross-connection of a digital signal or its constituent parts.

Източник: Internetworking Terms and Acronyms, June 1999

DCT

discrete cosine transform.

Източник: Internetworking Terms and Acronyms, June 1999

D channel

1. data channel. Full-duplex, 16-kbps (BRI) or 64-kbps (PRI) ISDN channel. Compare with B channel, E channel, and H channel. 2. In SNA, a device that connects a processor and main storage with peripherals.

Източник: Internetworking Terms and Acronyms, June 1999

DDE

Dynamic Data Exchange

Източник: A+ Certification Training Kit

DDM

distributed data management
Описание :
Software in an IBM SNA environment that provides peer-to-peer communication and file sharing. One of three SNA transaction services. See also DIA and SNADS.

Източник: Internetworking Terms and Acronyms, June 1999

DDN

Defense Data Network
Описание :
U.S. military network composed of an unclassified network (MILNET) and various secret and top-secret networks. DDN is operated and maintained by DISA. See also DISA and MILNET

Източник: Internetworking Terms and Acronyms, June 1999

DDP

Datagram Delivery Protocol
Описание :
AppleTalk network layer protocol that is responsible for the socket-to-socket delivery of datagrams over an AppleTalk internetwork.

Източник: Internetworking Terms and Acronyms, June 1999

DDR

dial-on-demand routing
Описание :
Technique whereby a router can automatically initiate and close a circuit-switched session as transmitting stations demand. The router spoofs keepalives so that end stations treat the session as active. DDR permits routing over ISDN or telephone lines using an external ISDN terminal adaptor or modem.

Източник: Internetworking Terms and Acronyms, June 1999

DE

discard eligible

Източник: Internetworking Terms and Acronyms, June 1999

DECnet

Group of communications products (including a protocol suite) developed and supported by Digital Equipment Corporation. DECnet/OSI (also called DECnet Phase V) is the most recent iteration and supports both OSI protocols and proprietary Digital protocols. Phase IV Prime supports inherent MAC addresses that allow DECnet nodes to coexist with systems running other protocols that have MAC address restrictions. See also DNA

Източник: Internetworking Terms and Acronyms, June 1999

DEK

data encryption key
Описание :
Used for the encryption of message text and for the computation of message integrity checks (signatures).

Източник: Internetworking Terms and Acronyms, June 1999

DES

1. Data Encryption Standard. Standard cryptographic algorithm developed by the U.S. National Bureau of Standards. 2. destination end station.

Източник: Internetworking Terms and Acronyms, June 1999

DHCP

Dynamic Host Configuration Protocol
Описание :
Provides a mechanism for allocating IP addresses dynamically so that addresses can be reused when hosts no longer need them.

Източник: Internetworking Terms and Acronyms, June 1999

DIA

Document Interchange Architecture
Описание :
Defines the protocols and data formats needed for the transparent interchange of documents in an SNA network. One of three SNA transaction services. See also DDM and SNADS

Източник: Internetworking Terms and Acronyms, June 1999

DIMM

Dual Inline Memory Module

Вижте също : SIMM, RAM

Източник: A+ Certification Training Kit

DIN

Deutsche Industrie Norm
Описание :
German national standards organization.

Източник: Internetworking Terms and Acronyms, June 1999

DIPP

Dual inline pin package

Източник: A+ Certification Training Kit

DISA

Defense Information Systems Agency
Описание :
Formerly DCA. U.S. military organization responsible for implementing and operating military information systems, including the DDN. See also DDN and dBm

Източник: Internetworking Terms and Acronyms, June 1999

DLCI

data-link connection identifier
Описание :
Value that specifies a PVC or SVC in a Frame Relay network. In the basic Frame Relay specification, DLCIs are locally significant (connected devices might use different values to specify the same connection). In the LMI extended specification, DLCIs are globally significant (DLCIs specify individual end devices). See also LMI

Източник: Internetworking Terms and Acronyms, June 1999

DLL

Dynamic Link Library

Източник: Internetworking Terms and Acronyms, June 1999

DLSw

data-link switching
Описание :
Interoperability standard, described in RFC 1434, that provides a method for forwarding SNA and NetBIOS traffic over TCP/IP networks using data-link layer switching and encapsulation. DLSw uses SSP instead of SRB, eliminating the major limitations of SRB, including hop-count limits, broadcast and unnecessary traffic, timeouts, lack of flow control, and lack of prioritization schemes. See also SRB and SSP (Switch-to-Switch Protocol)

Източник: Internetworking Terms and Acronyms, June 1999

DLSw+

Data-Link Switching plus
Описание :
Cisco implementation of the DLSw standard for SNA and NetBIOS traffic forwarding. DLSw+ goes beyond the standard to include the advanced features of the current Cisco RSRB implementation, and provides additional functionality to increase the overall scalability of data-link switching. See also DLSw .

Източник: Cisco Systems Terms and Acronyms

DLU

Dependent LU
Описание :
LU that depends on the SSCP to provide services for establishing sessions with other LUs. See also LU and SSCP

Източник: Internetworking Terms and Acronyms, June 1999

DLUR

Dependent LU Requester
Описание :
Client half of the Dependent LU Requestor/Server enhancement to APPN. The DLUR component resides in APPN ENs and NNs that support adjacent DLUs by securing services from the DLUS. See also APPN, DLU, and DLUS

Източник: Internetworking Terms and Acronyms, June 1999

DLUS

Dependent LU Server
Описание :
Server half of the Dependent LU Requestor/Server enhancement to APPN. The DLUS component provides SSCP services to DLUR nodes over an APPN network. See also APPN, DLU, and DLUR

Източник: Internetworking Terms and Acronyms, June 1999

DMA

Direct Memory Access
Описание :
Transfer of data from a peripheral device, such as a hard disk drive, into memory without that data passing through the microprocessor. DMA transfers data into memory at high speeds with no processor overhead.

Източник: Internetworking Terms and Acronyms, June 1999

DMAC

destination MAC
Описание :
The MAC address specified in the Destination Address field of a packet. Compare with SMAC. See also MAC address.

Източник: Internetworking Terms and Acronyms, June 1999

DMP

Data Movement Processor
Описание :
Processor on the Catalyst 5000 that, along with the multiport packet buffer memory interface, performs the frame-switching function for the switch. The DMP also handles translational bridging between the Ethernet and FDDI interfaces, IP segmentation, and intelligent bridging with protocol-based filtering.

Източник: Cisco Systems Terms and Acronyms

DN

Distinguished Name
Описание :
Global, authoritative name of an entry in the OSI Directory (X.500).

Източник: Internetworking Terms and Acronyms, June 1999

DNA

Digital Network Architecture
Описание :
Network architecture developed by Digital Equipment Corporation. The products that embody DNA(including communications protocols) are collectively referred to as DECnet. See also DECnet

Източник: Internetworking Terms and Acronyms, June 1999

DNIC

Data Network Identification Code
Описание :
Part of an X.121 address. DNICs are divided into two parts: the first specifying the country in which the addressed PSN is located and the second specifying the PSN itself. See also X.121

Източник: Internetworking Terms and Acronyms, June 1999

DNS

Domain Name System
Описание :
System used in the Internet for translating names of network nodes into addresses.

Източник: Internetworking Terms and Acronyms, June 1999

DNSIX

Department of Defense Intelligence Information System Network Security for Information Exchange
Описание :
Collection of security requirements for networking defined by the U.S. Defense Intelligence Agency.

Източник: Internetworking Terms and Acronyms, June 1999

DOCSIS

Data-over-Cable Service Interface Specifications
Описание :
Defines technical specifications for equipment at both subscriber locations and cable operators’ headends. Adoption of DOCSIS will accelerate deployment of data-over-cable services and ensure interoperability of equipment throughout system operators’ infrastructures. Document Interchange Architecture See DIA.

Източник: Internetworking Terms and Acronyms, June 1999

DoD

Department of Defense
Описание :
U.S. government organization that is responsible for national defense. The DoD has frequently funded communication protocol development.

Източник: Internetworking Terms and Acronyms, June 1999

DOS

Disk Operating System

Източник: A+ Certification Training Kit

dpi

Dots per Inch

Източник: A+ Certification Training Kit

DPMI

MS-DOS Protected Mode Interface

Източник: A+ Certification Training Kit

DPMS

Display Power Management Signaling

Източник: A+ Certification Training Kit

DQDB

Distributed Queue Dual Bus
Описание :
Data-link layer communication protocol, specified in the IEEE 802.6 standard, designed for use in MANs. DQDB, which permits multiple systems to interconnect using two unidirectional logical buses, is an open standard that is designed for compatibility with carrier transmission standards, and is aligned with emerging standards for BISDN. SIP is based on DQDB. See also MAN

Източник: Internetworking Terms and Acronyms, June 1999

DRAM

dynamic random-access memory
Описание :

Динамичните памети са изградени на електростатично заредени кондензаторни елементи. Като всеки реален кондензатор след зареждане започва неговото разреждане и потенциала пада след определено време 10-15 us. Това налага периодично възстановяване на заряда на кондензатора чрез четене или запис. Това действие се нарича опресняване (Refresh) и трябва да се извършва непрекъснато докато работи компютъра с периодичност 80-100 kHz . DRAM паметите са по-лесни за изработка и са с по-голям капацитет спрямо SRAM.

Сравнете с : SRAM

DRDA

Distributed Relational Database Architecture
Описание :
IBM proprietary architecture.

Източник: Internetworking Terms and Acronyms, June 1999

DRP

Director Response Protocol
Описание :
Protocol used by the DistributedDirector feature in IP routing.

Източник: Cisco Systems Terms and Acronyms

DS-0

digital signal level 0
Описание :
Framing specification used in transmitting digital signals over a single channel at 64-kbps on a T1 facility. Compare with DS-1 and DS-3

Източник: Internetworking Terms and Acronyms, June 1999

DS-1

digital signal level 1
Описание :
Framing specification used in transmitting digital signals at 1.544-Mbps on a T1 facility (in the United States) or at 2.108-Mbps on an E1 facility (in Europe). Compare with DS-0 and DS-3. See also E1 and T1

Източник: Internetworking Terms and Acronyms, June 1999

DS-3

digital signal level 3
Описание :
Framing specification used for transmitting digital signals at 44.736 Mbps on a T3 facility. Compare with DS-0 and DS-1 See also E3 and T.120

Източник: Internetworking Terms and Acronyms, June 1999

DSA

Directory System Agent
Описание :
Software that provides the X.500 Directory Service for a portion of the directory information base. Generally, each DSA is responsible for the directory information for a single organization or organizational unit.

Източник: Internetworking Terms and Acronyms, June 1999

DSAP

destination service access point
Описание :
SAP of the network node designated in the Destination field of a packet. Compare with SSAP See also SAP (service access point)

Източник: Internetworking Terms and Acronyms, June 1999

DSL

digital subscriber line
Описание :
Public network technology that delivers high bandwidth over conventional copper wiring at limited distances. There are four types of DSL: ADSL, HDSL, SDSL, and VDSL. All are provisioned via modem pairs, with one modem located at a central office and the other at the customer site. Because most DSL technologies do not use the whole bandwidth of the twisted pair, there is room remaining for a voice channel. See also ADSL, HDSL, SDSL, and VDSL

Източник: Internetworking Terms and Acronyms, June 1999

DSP

domain specific part
Описание :
Part of an NSAP-format ATM address that contains an area identifier, a station identifier, and a selector byte. See also NSAP

Източник: Internetworking Terms and Acronyms, June 1999

DSPU

downstream physical unit

Описание :
In SNA, a PU that is located downstream from the host.

Източник: Internetworking Terms and Acronyms, June 1999

DSR

data set ready
Описание :
EIA/TIA-232 interface circuit that is activated when DCE is powered up and ready for use.

Източник: Internetworking Terms and Acronyms, June 1999

DSU

data service unit
Описание :
Device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T1 or E1. The DSU is also responsible for such functions as signal timing. Often referred to together with CSU, as CSU/DSU. See also CSU

Източник: Internetworking Terms and Acronyms, June 1999

DSX-1

Crossconnection point for DS-1 signals.

Източник: Internetworking Terms and Acronyms, June 1999

DTE

data terminal equipment
Описание :
Device at the user end of a user-network interface that serves as a data source, destination, or both. DTE connects to a data network through a DCE device (for example, a modem) and typically uses clocking signals generated by the DCE. DTE includes such devices as computers, protocol translators, and multiplexers. Compare with DCE

Източник: Internetworking Terms and Acronyms, June 1999

DTL

designated transit list
Описание :
List of nodes and optional link IDs that completely specify a path across a single PNNI peer group.

Източник: Internetworking Terms and Acronyms, June 1999

DTMF

dual tone multifrequency
Описание :
Use of two simultaneous voice-band tones for dialing (such as touch tone).

Източник: Internetworking Terms and Acronyms, June 1999

DTR

data terminal ready
Описание :
EIA/TIA-232 circuit that is activated to let the DCE know when the DTE is ready to send and receive data.

Източник: Internetworking Terms and Acronyms, June 1999

DUA

Directory User Agent
Описание :
Software that accesses the X.500 Directory Service on behalf of the directory user. The directory user can be a person or another software element.

Източник: Internetworking Terms and Acronyms, June 1999

DUAL


Diffusing Update Algorithm


Описание :
Convergence algorithm used in Enhanced IGRP that provides loop-free operation at every instant throughout a route computation. Allows routers involved in a topology change to synchronize at the same time, while not involving routers that are unaffected by the change. See also Enhanced IGRP.

Източник: Cisco Systems Terms and Acronyms

DVMRP

Distance Vector Multicast Routing Protocol


Описание :
Internetwork gateway protocol, largely based on RIP, that implements a typical dense mode IP multicast scheme. DVMRP uses IGMP to exchange routing datagrams with its neighbors. See also IGMP

Източник: Internetworking Terms and Acronyms, June 1999

DXI

Data Exchange Interface
Описание :
ATM Forum specification, described in RFC 1483, that defines how a network device such as a bridge, router, or hub can effectively act as an FEP to an ATM network by interfacing with a special DSU that performs packet segmentation and reassembly.

Източник: Internetworking Terms and Acronyms, June 1999

E1


Описание :
Wide-area digital transmission scheme used predominantly in Europe that carries data at a rate of 2.048 Mbps. E1 lines can be leased for private use from common carriers. Compare with T1 See also DS-1

Източник: Internetworking Terms and Acronyms, June 1999

E2A


Описание :
Legacy protocols for providing OAM&P functions between a network element and an operations support system. See also OAM&P

Източник: Internetworking Terms and Acronyms, June 1999

E3

Wide-area digital transmission scheme used predominantly in Europe that carries data at a rate of 34.368 Mbps. E3 lines can be leased for private use from common carriers. Compare with T.120 See also DS-3

Източник: Internetworking Terms and Acronyms, June 1999

EARN

European Academic Research Network
Описание :
European network connecting universities and research institutes. EARN merged with RARE to form TERENA. See also RARE and TERENA

Източник: Internetworking Terms and Acronyms, June 1999

EBCDIC

extended binary coded decimal interchange code
Описание :
Any of a number of coded character sets developed by IBM consisting of 8-bit coded characters. This character code is used by older IBM systems and telex machines. Compare with ASCII

Източник: Internetworking Terms and Acronyms, June 1999

EBONE

European Backbone
Описание :
Pan-European network backbone service.

Източник: Internetworking Terms and Acronyms, June 1999

EC

European Community.

Източник: Internetworking Terms and Acronyms, June 1999

ECMA

European Computer Manufacturers Association
Описание :
Group of European computer vendors who have done substantial OSI standardization work.

Източник: Internetworking Terms and Acronyms, June 1999

EDB

External data bus

Източник: Internetworking Terms and Acronyms, June 1999

EDIFACT

Electronic Data Interchange for Administration, Commerce, and Transport
Описание :
Data exchange standard administered by the United Nations to be a multi-industry EDI standard.

Източник: Internetworking Terms and Acronyms, June 1999

EDO

Extended data out

Източник: A+

EECM

end-to-end call manager.

Източник: Internetworking Terms and Acronyms, June 1999

EEPROM

electrically erasable programmable read-only memory

Описание :
EPROM that can be erased using electrical signals applied to specific pins. See also EPROM

Източник: Internetworking Terms and Acronyms, June 1999

EFCI

Explicit Forward Congestion Indication

Описание :
In ATM, one of the congestion feedback modes allowed by ABR service. A network element in an impending congestion state or in a congested state can set the EFCI. The destination end-system can implement a protocol that adaptively lowers the cell rate of the connection based on the value of the EFCI. See also ABR

Източник: Internetworking Terms and Acronyms, June 1999

EFF

Electronic Frontier Foundation

Описание :
Foundation established to address social and legal issues arising from the impact on society of the increasingly pervasive use of computers as the means of communication and information distribution.

Източник: Internetworking Terms and Acronyms, June 1999

EGA

Enhanced Graphics Adapter

EGP

Exterior Gateway Protocol

Описание :
Internet protocol for exchanging routing information between autonomous systems. Documented in RFC 904. Not to be confused with the general term exterior gateway protocol. EGP is an obsolete protocol that was replaced by BGP. See also BGP

Източник: Internetworking Terms and Acronyms, June 1999

EIA

Electronic Industries Association

Описание :
Group that specifies electrical transmission standards. The EIA and TIA have developed numerous well-known communications standards, including EIA/TIA-232 and EIA/TIA-449. See also TIA

Източник: Internetworking Terms and Acronyms, June 1999

EIA-530



Описание :
Refers to two electrical implementations of EIA/TIA-449: RS-422 (for balanced transmission) and RS-423 (for unbalanced transmission). See also RS-422, RS-423, and EIA/TIA-449

Източник: Internetworking Terms and Acronyms, June 1999

EIA/TIA-232



Описание :
Common physical layer interface standard, developed by EIA and TIA, that supports unbalanced circuits at signal speeds of up to 64 kbps. Closely resembles the V.24 specification. Formerly called as RS-232.

Източник: Internetworking Terms and Acronyms, June 1999

EIA/TIA-449



Описание :
Popular physical layer interface developed by EIA and TIA. Essentially, a faster (up to 2 Mbps) version of EIA/TIA-232 capable of longer cable runs. Formerly called RS-449. See also EIA-530

Източник: Internetworking Terms and Acronyms, June 1999

EIA/TIA-586



Описание :
Standard that describes the characteristics and applications for various grades of UTP cabling. See also Category 1 cabling, Category 2 cabling, Category 3 cabling, Category 4 cabling, Category 5 cabling, and UTC.

Източник: Internetworking Terms and Acronyms, June 1999

EIDE

Enhanced Integrated Drive Electronics

Източник: Internetworking Terms and Acronyms, June 1999

EIGRP

Enhanced Interior Gateway Routing Protocol

Описание :
Advanced version of IGRP developed by Cisco. Provides superior convergence properties and operating efficiency, and combines the advantages of link state protocols with those of distance vector protocols. Compare with IGRP. See also IGP, OSPF, and RIP. Cisco Systems Terms and Acronyms

EIP

Ethernet Interface Processor

Описание :
Interface processor card on the Cisco 7000 series routers. The EIP provides high-speed (10-Mbps) AUI ports that support Ethernet Version 1 and Ethernet Version 2 or IEEE 802.3 interfaces, and a high-speed data path to other interface processors. Cisco Systems Terms and Acronyms

EISA

Extended Industry-Standard Architecture

Описание :
32-bit bus interface used in PCs, PC-based servers, and some UNIX workstations and servers. See also ISA

Източник: Internetworking Terms and Acronyms, June 1999

ELAN

emulated LAN

Описание :
ATM network in which an Ethernet or Token Ring LAN is emulated using a client-server model. ELANs are composed of an LEC, an LES, a BUS, and an LECS. Multiple ELANs can exist simultaneously on a single ATMnetwork. ELANs are defined by the LANE specification. See also BUS, LANE, LEC, LECS, and LES

Източник: Internetworking Terms and Acronyms, June 1999

ELAP

EtherTalk Link Access Protocol

Описание :
Link-access protocol used in an EtherTalk network. ELAP is built on top of the standard Ethernet data link layer.

Източник: Internetworking Terms and Acronyms, June 1999

ELMI

Enhanced Local Management Interface.

Източник: Internetworking Terms and Acronyms, June 1999

EMA

1. Enterprise Management Architecture

Описание :
Digital Equipment Corporation network management architecture, based on the OSI network management model.

2. Electronic Messaging Association

Описание :
Forum devoted to standards and policy work, education, and development of electronic messaging systems such as e-mail, voice mail, and facsimile.

Източник: Internetworking Terms and Acronyms, June 1999

email

electronic mail

Описание :
Widely used network application in which text messages are transmitted electronically between end users over various types of networks using various network protocols.

Източник: Internetworking Terms and Acronyms, June 1999

EMI

electromagnetic interference

Описание :
Interference by electromagnetic signals that can cause reduced data integrity and increased error rates on transmission channels.

Източник: Internetworking Terms and Acronyms, June 1999

EMIF

ESCON Multiple Image Facility

Описание :
Mainframe I/O software function that allows one ESCON channel to be shared among multiple logical partitions on the same mainframe. See also ESCON

Източник: Internetworking Terms and Acronyms, June 1999

EMP

electromagnetic pulse

Описание :
Caused by lightning and other high-energy phenomena. Capable of coupling enough energy into unshielded conductors to destroy electronic devices. See also Tempest

Източник: Internetworking Terms and Acronyms, June 1999

EMS

Expanded Memory Specification A+ Certification Training Kit

EN

end node

Описание :
APPN end system that implements the PU 2.1, provides end-user services, and supports sessions between local and remote CPs. ENs are not capable of routing traffic and rely on an adjacent NN for APPN services. Compare with NN See also CP

Източник: Internetworking Terms and Acronyms, June 1999

ENIAC

Electronic Numerical Integrator and Computer

Описание :

Найменованието на един от първите компютри, разработен от проф. Джон Мочли и проф. Дж. Екерт в университета на щат Пенсилвания и завършен през 1946г. в училището по електроинженерство на Пенсилванския университет. Машината е била разработена като универслана, но се е използвала за решаване на обикновени диференциални уравнения. Тя е десетична машина - числата се представят в код от "1 от 10" чрез 10 десет разрядни десетични числа представени с двоично кодиране. Отрицателните числа се представят в обратен код. Има 18 000 електронни лампи и консумираната мощност е 150 kWA.

EOM

end of message

Описание :
Indicator that identifies the last ATM cell containing information from a data packet that was segmented.

Източник: Internetworking Terms and Acronyms, June 1999

EOT

end of transmission

Описание :
Generally, a character that signifies the end of a logical group of characters or bits.

Източник: Internetworking Terms and Acronyms, June 1999

EPD

early packet discard

Описание :
Mechanism used by some ATMswitches for discarding a complete AAL5 frame when a threshold condition, such as imminent congestion, is met. EPD prevents congestion that would otherwise jeopardize the switch’s ability to properly support existing connections with a guaranteed service. Compare with TPD

Източник: Internetworking Terms and Acronyms, June 1999

EPROM

erasable programmable read-only memory

Описание :
Nonvolatile memory chips that are programmed after they are manufactured, and, if necessary, can be erased by some means and reprogrammed. Compare with EECM and PROM

Източник: Internetworking Terms and Acronyms, June 1999

ER

explicit rate

Описание :
In ATM, an RM cell used to limit the ACR for a transmission to a specific value. Usually the source initially sets the ER initially to a requested rate, such as the PCR. Later, any network element in the path can reduce the ER to a value that the element can sustain. See also ACOM, PCR, and RLM

Източник: Internetworking Terms and Acronyms, June 1999

ES


1. end system

Описание :
Generally, an end-user device on a network.

2. end system

Описание :
Nonrouting host or node in an OSI network.

Източник: Internetworking Terms and Acronyms, June 1999

ESI

end system identifier

Описание :
Identifier that distinguishes multiple nodes at the same level when the lower level peer group is partitioned (usually an IEEE 802 address).

Източник: Internetworking Terms and Acronyms, June 1999

ESCON

Enterprise System Connection

Описание :
IBM channel architecture that specifies a pair of fiber-optic cables, with either LEDs or lasers as transmitters, and a signaling rate of 200 Mbps.

Източник: Internetworking Terms and Acronyms, June 1999

ESD

electrostatic discharge

Описание :
Discharge of stored static electricity that can damage electronic equipment and impair electrical circuitry, resulting in complete or intermittent failures.

Източник: Internetworking Terms and Acronyms, June 1999

ESDI

Enhanced Small Device Interface A+ Certification Training Kit

ESF

Extended Superframe

Описание :
Framing type used on T1 circuits that consists of 24 frames of 192 bits each, with the 193rd bit providing timing and other functions. ESF is an enhanced version of SF. See also SF

Източник: Internetworking Terms and Acronyms, June 1999

ES-IS

End System-to-Intermediate System

Описание :
OSI protocol that defines how end systems (hosts) announce themselves to intermediate systems (routers). See also IS-IS

Източник: Internetworking Terms and Acronyms, June 1999

ESMTP

Extended Simple Mail Transfer Protocol

Описание :
Extended version of the Simple Mail Transfer Protocol (SMTP), which includes additional functionality such as delivery notification and session delivery. ESMTP is described in RFC 1869, SMTP Service Extensions.

ESnet

Energy Sciences Network

Описание :
Data communications network managed and funded by the U.S. Department of Energy Office of Energy Research (DOE/OER). Interconnects the DOE to educational institutions and other research facilities.

Източник: Internetworking Terms and Acronyms, June 1999

ESP

Extended Services Processor

Описание :
Rack-mounted adjunct processor that is co-located with a Cisco BPX/AXIS (all three units comprise a BPX service node) and has IP connectivity to a StrataView Plus Workstation. Cisco Systems Terms and Acronyms

ESS

Electronic Switching System

Описание :
AT&T’s term for an electronic central office switch. A 5ESS is AT&T’s digital central office for end office applications. A 4ESS is its digital central office for toll center application.

Източник: Internetworking Terms and Acronyms, June 1999

Ethernet



Описание :
Baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation. Ethernet networks use CSMA/CD and run over a variety of cable types at 10 Mbps. Ethernet is similar to the IEEE 802.3 series of standards. See also 10Base2, 10Base5, 10BaseF, 10BaseT, 10Broad36

Източник: Internetworking Terms and Acronyms, June 1999

ETSI

European Telecommunication Standards Institute

Описание :
Organization created by the European PTTs and the EC to propose telecommunications standards for Europe.

Източник: Internetworking Terms and Acronyms, June 1999

ETX

End-of-text A+ Certification Training Kit

EUnet

European Internet

Описание :
European commercial Internet service provider. EUnet is designed to provide e-mail, news, and other Internet services to European markets.

Източник: Internetworking Terms and Acronyms, June 1999

EWOS

European Workshop for Open Systems

Описание :
The OSI Implementors Workshop for Europe.

Източник: Internetworking Terms and Acronyms, June 1999

EXEC

Interactive command processor of Cisco IOS. Cisco Systems Terms and Acronyms

EXZ

excessive zeros.

Източник: Internetworking Terms and Acronyms, June 1999

FAQ

frequently asked questions

Описание :
Usually appears in the form of a “read-me” file in a variety of Internet forums. New users are expected to read the FAQ before participating in newsgroups, bulletin boards, video conferences, and so on.

Източник: Internetworking Terms and Acronyms, June 1999

FARNET

Federation of American Research NETworks.

Източник: Internetworking Terms and Acronyms, June 1999

FAT

File allocation table A+ Certification Training Kit

FCC

Federal Communications Commission

Описание :
U.S. government agency that supervises, licenses, and controls electronic and electromagnetic transmission standards.

Източник: Internetworking Terms and Acronyms, June 1999

FCFS

first come first served

Източник: Internetworking Terms and Acronyms, June 1999

FCS

frame check sequence

Описание :
Extra characters added to a frame for error control purposes. Used in HDLC, Frame Relay, and other data link layer protocols.

Източник: Internetworking Terms and Acronyms, June 1999

FDDI

Fiber Distributed Data Interface

Описание :
LAN standard, defined by ANSI X3T9.5, specifying a 100-Mbps token-passing network using fiber-optic cable, with transmission distances of up to 2 km. FDDI uses a dual-ring architecture to provide redundancy. Compare with CDDI and FDDI II

Източник: Internetworking Terms and Acronyms, June 1999

FDDI II

ANSI standard that enhances FDDI

Описание :
FDDI II provides isochronous transmission for connectionless data circuits and connection-oriented voice and video circuits. Compare with FDDI

Източник: Internetworking Terms and Acronyms, June 1999

FDM

frequency-division multiplexing

Описание :
Technique whereby information from multiple channels can be allocated bandwidth on a single wire based on frequency. Compare with ATDM, statistical multiplexing, and TDM

Източник: Internetworking Terms and Acronyms, June 1999

FE

Fast Ethernet

Източник: Internetworking Terms and Acronyms, June 1999

FECN

forward explicit congestion notification

Описание :
Bit set by a Frame Relay network to inform DTE receiving the frame that congestion was experienced in the path from source to destination. DTE receiving frames with the FECN bit set can request that higher-level protocols take flow-control action as appropriate. Compare with BECN

Източник: Internetworking Terms and Acronyms, June 1999

FEIP

Fast Ethernet Interface Processor

Описание :
Interface processor on the Cisco 7000 series routers. The FEIP supports up to two 100-Mbps 100BaseT ports. Cisco Systems Terms and Acronyms

FEP

front-end processor

Описание :
Device or board that provides network interface capabilities for a networked device. In SNA, typically an IBM 3745 device.

Източник: Internetworking Terms and Acronyms, June 1999

FGD

Feature Group-D

Източник: Internetworking Terms and Acronyms, June 1999

FID0

format indicator 0

Описание :
One of several formats that an SNA TH can use. An FID0 TH is used for communication between an SNA node and a non-SNA node. See also TH

Източник: Internetworking Terms and Acronyms, June 1999

FID1

format indicator

Описание :
One of several formats that an SNA TH can use. An FID1 TH encapsulates messages between two subarea nodes that do not support virtual and explicit routes. See also TH

Източник: Internetworking Terms and Acronyms, June 1999

FID2

format indicator 2

Описание :
One of several formats that an SNA TH can use. An FID2 TH is used for transferring messages between a subarea node and a PU 2, using local addresses. See also TH

Източник: Internetworking Terms and Acronyms, June 1999

FID3

format indicator 3

Описание :
One of several formats that an SNA TH can use. An FID3 TH is used for transferring messages between a subarea node and a PU 1, using local addresses. See also TH

Източник: Internetworking Terms and Acronyms, June 1999

FID4

format indicator 4

Описание :
One of several formats that an SNA TH can use. An FID4 TH encapsulates messages between two subarea nodes that are capable of supporting virtual and explicit routes.
See also TH

Източник: Internetworking Terms and Acronyms, June 1999

FIP

FDDI Interface Processor

Описание :
Interface processor on the Cisco 7000 series routers. The FIP supports SASs, DASs, dual homing, and optical bypass, and contains a 16-mips processor for high-speed (100-Mbps) interface rates. The FIP complies with ANSI and ISO FDDI standards. Cisco Systems Terms and Acronyms

firmware



Описание :
Software instructions set permanently or semipermanently in ROM.

Източник: Internetworking Terms and Acronyms, June 1999

FIX

Federal Internet Exchange

Описание :
Connection point between the North American governmental internets and the Internet. The FIXs are named after their geographic region, as in FIX West (Mountain View, California) and FIX East (College Park, Maryland).
See CIX, GIX, and MAE

Източник: Internetworking Terms and Acronyms, June 1999

F-link



Описание :
SS7 fully associated link. An SS7 signaling link directly associated with a link carrying traffic.

Източник: Internetworking Terms and Acronyms, June 1999

flooding



Описание :
Traffic passing technique used by switches and bridges in which traffic received on an interface is sent out all of the interfaces of that device except the interface on which the information was originally received.

Източник: Internetworking Terms and Acronyms, June 1999

FLT

Full Line Terminal

Описание :
Multiplexer that terminates a SONET span.
See also SONET

Източник: Internetworking Terms and Acronyms, June 1999

FM

frequency modulation

Описание :
Modulation technique in which signals of different frequencies represent different data values.
Compare with AM and PAM

Източник: Internetworking Terms and Acronyms, June 1999

FNC

Federal Networking Council

Описание :
Group responsible for assessing and coordinating U.S. federal agency networking policies and needs.

Източник: Internetworking Terms and Acronyms, June 1999

FOIRL

fiber-optic interrepeater link

Описание :
Fiber-optic signaling methodology based on the IEEE 802.3 fiber-optic specification. FOIRL is a precursor of the 10BaseFL specification, which is designed to replace it.
See also 10BaseFL

Източник: Internetworking Terms and Acronyms, June 1999

FOTS

Fiber Optics Transmission Systems

Описание :
Vendor-proprietary fiber-optic transmission equipment.

Източник: Internetworking Terms and Acronyms, June 1999

FPM

Fast-page mode A+ Certification Training Kit

FQDN

fully qualified domain name

Описание :
FQDN is the full name of a system, rather than just its host name. For example, aldebaran is a host name, and aldebaran.interop.com is an FQDN.

Източник: Internetworking Terms and Acronyms, June 1999

FRAD

Frame Relay access device

Описание :
Any network device that provides a connection between a LAN and a Frame Relay WAN. See also FRAS

Източник: Internetworking Terms and Acronyms, June 1999

FRAS

Frame Relay access support

Описание :
Cisco IOS feature that allows SDLC, Token Ring, Ethernet, and Frame Relay-attached IBM devices to connect to other IBM devices across a Frame Relay network. See also FRAD. Cisco Systems Terms and Acronyms

FRASM

Frame Relay access service module

Източник: Internetworking Terms and Acronyms, June 1999

freenet



Описание :
Community-based bulletin board system with e-mail, information services, interactive communications, and conferencing.

Източник: Internetworking Terms and Acronyms, June 1999

FRF

Frame Relay Forum

Описание :
An association of corporate members consisting of vendors, carriers, users and consultants committed to the implementation of Frame Relay in accordance with national and international standards. See www.frforum.com.

Източник: Internetworking Terms and Acronyms, June 1999

FRF.11



Описание :
Frame Relay Forum implementation agreement for Voice over Frame Relay (v1.0 May 1997). This specification defines multiplexed data, voice, fax, DTMF digit-relay and CAS/Robbed-bit signaling frame formats, but does not include call setup, routing or administration facilities. See www.frforum.com

Източник: Internetworking Terms and Acronyms, June 1999

FRMR

Frame REJECT

Източник: Internetworking Terms and Acronyms, June 1999

FSIP

Fast Serial Interface Processor

Описание :
Default serial interface processor for Cisco 7000 series routers. The FSIP provides four or eight high-speed serial ports. Cisco Systems Terms and Acronyms

FST

Fast Sequenced Transport Connectionless, sequenced transport protocol that runs on top of the IP protocol. SRB traffic is encapsulated inside of IP datagrams and is passed over an FST connection between two network devices (such as routers). Speeds up data delivery, reduces overhead, and improves the response time of SRB traffic. Cisco Systems Terms and Acronyms

FTAM

File Transfer, Access, and Management

Описание :
In OSI, an application layer protocol developed for network file exchange and management between diverse types of computers.

Източник: Internetworking Terms and Acronyms, June 1999

FTP

File Transfer Protocol

Описание :
Application protocol, part of the TCP/IP protocol stack, used for transferring files between network nodes. FTP is defined in RFC 959.

Източник: Internetworking Terms and Acronyms, June 1999

FUNI

frame user network interface

Източник: Internetworking Terms and Acronyms, June 1999

FXO

Foreign Exchange Office

Описание :
An FXO interface connects to the Public Switched Telephone Network’s (PSTN) central office and is the interface offered on a standard telephone. Cisco’s FXO interface is an RJ-11 connector that allows an analog connection to be directed at the PSTN’s central office or to a station interface on a PBX.

Източник: Internetworking Terms and Acronyms, June 1999

FXS

Foreign Exchange Station

Описание :
An FXS interface connects directly to a standard telephone and supplies ring, voltage, and dial tone. Cisco’s FXS interface is an RJ-11 connector that allows connections to basic telephone service equipment, keysets, and PBXes.

Източник: Internetworking Terms and Acronyms, June 1999

G.711



Описание :
Describes the 64-kbps PCM voice coding technique. In G.711, encoded voice is already in the correct format for digital voice delivery in the PSTN or through PBXs. Described in the ITU-T standard in its G-series recommendations.

Източник: Internetworking Terms and Acronyms, June 1999

G.723.1



Описание :
Describes a compression technique that can be used for compressing speech or audio signal components at a very low bit rate as part of the H.324 family of standards. This CODEC has two bit rates associated with it: 5.3 and 6.3 kbps. The higher bit rate is based on ML-MLQ technology and provides a somewhat higher quality of sound. The lower bit rate is based on CELP and provides system designers with additional flexibility. Described in the ITU-T standard in its G-series recommendations.

Източник: Internetworking Terms and Acronyms, June 1999

G.726



Описание :
Describes ADPCM coding at 40, 32, 24, and 16 kbps. ADPCM-encoded voice can be interchanged between packet voice, PSTN, and PBX networks if the PBX networks are configured to support ADPCM. Described in the ITU-T standard in its G-series recommendations.

Източник: Internetworking Terms and Acronyms, June 1999

G.728

Describes a 16-kbps low-delay variation of CELP voice compression. CELP voice coding must be translated into a public telephony format for delivery to or through the PSTN. Described in the ITU-T standard in its G-series recommendations.

Източник: Internetworking Terms and Acronyms, June 1999

G.729

Describes CELP compression where voice is coded into 8-kbps streams. There are two variations of this standard (G.729 and G.729 Annex A) that differ mainly in computational complexity; both provide speech quality similar to 32-kbps ADPCM. Described in the ITU-T standard in its G-series recommendations.

Източник: Internetworking Terms and Acronyms, June 1999

G.804

ITU-T framing standard that defines the mapping of ATM cells into the physical medium.

Източник: Internetworking Terms and Acronyms, June 1999

GB

gigabyte Approximately 1,000,000,000 bytes.

Източник: Internetworking Terms and Acronyms, June 1999

GBps

gigabytes per second

Източник: Internetworking Terms and Acronyms, June 1999

Gb

gigabit Approximately 1,000,000,000 bits

Източник: Internetworking Terms and Acronyms, June 1999

Gbps

gigabits per second

Източник: Internetworking Terms and Acronyms, June 1999

GCAC

generic connection admission control In ATM, a PNNI algorithm designed for CBR and VBR connections. Any node can use GCAC to calculate the expected CAC behavior of another node given than node’s advertised link metrics and the QoS of a connection setup request.
See also CAC

Източник: Internetworking Terms and Acronyms, June 1999

GCRA

generic cell rate algorithm In ATM, an algorithm that defines conformance with respect to the traffic contract of the connection. For each cell arrival, the GCRA determines whether the cell conforms to the traffic contract.

Източник: Internetworking Terms and Acronyms, June 1999

GDP

Gateway Discovery Protocol Cisco protocol that allows hosts to dynamically detect the arrival of new routers as well as determine when a router goes down. Based on UDP. Cisco Systems Terms and Acronyms

GDI

Graphical Device Interface A+ Certification Training Kit

GGP

Gateway-to-Gateway Protocol. MILNET protocol specifying how core routers (gateways) should exchange reachability and routing information. GGP uses a distributed shortest-path algorithm.

Източник: Internetworking Terms and Acronyms, June 1999

GHz

gigahertz

Източник: Internetworking Terms and Acronyms, June 1999

GIX

Global Internet eXchange Common routing exchange point which allows pairs of networks to implement agreed-upon routing policies. The GIX is intended to allow maximum connectivity to the Internet for networks all over the world.
See CIX, FIX, and MAE

Източник: Internetworking Terms and Acronyms, June 1999

GNS

Get Nearest Server Request packet sent by a client on an IPX network to locate the nearest active server of a particular type. An IPX network client issues a GNS request to solicit either a direct response from a connected server or a response from a router that tells it where on the internetwork the service can be located. GNS is part of the IPX SAP.
See also IPX and SAP (Service Advertisement Protocol)

Източник: Internetworking Terms and Acronyms, June 1999

Gopher

distributed document delivery system. The Internet Gopher allows a neophyte user to access various types of data residing on multiple hosts in a seamless fashion.

Източник: Internetworking Terms and Acronyms, June 1999

GOSIP

Government OSI Profile U.S. government procurement specification for OSI protocols. Through GOSIP, the government mandates that all federal agencies standardize on OSI and implement OSI-based systems as they become commercially available.

Източник: Internetworking Terms and Acronyms, June 1999

GPF

General Protection Fault A+ Certification Training Kit

GRE

generic routing encapsulation Tunneling protocol developed by Cisco that can encapsulate a wide variety of protocol packet types inside IP tunnels, creating a virtual point-to-point link to Cisco routers at remote points over an IP internetwork. By connecting multiprotocol subnetworks in a single-protocol backbone environment, IP tunneling using GRE allows network expansion across a single-protocol backbone environment. Cisco Systems Terms and Acronyms

GSS

Generic Service State

Източник: Internetworking Terms and Acronyms, June 1999

GUI

graphical user interface User environment that uses pictorial as well as textual representations of the input and output of applications and the hierarchical or other data structure in which information is stored. Conventions such as buttons, icons, and windows are typical, and many actions are performed using a pointing device (such as a mouse). Microsoft Windows and the Apple Macintosh are prominent examples of platforms using a GUI.

Източник: Internetworking Terms and Acronyms, June 1999

H.225.0

An ITU standard that governs H.225.0 session establishment and packetization. H.225.0 actually describes several different protocols: RAS, use of Q.931, and use of RTP.

Източник: Internetworking Terms and Acronyms, June 1999

H.245

An ITU standard that governs H.245 endpoint control.

Източник: Internetworking Terms and Acronyms, June 1999

H.320

Suite of ITU-T standard specifications for videoconferencing over circuit-switched media such as ISDN, fractional T-1, and switched-56 lines.

Източник: Internetworking Terms and Acronyms, June 1999

H.323

Extension of ITU-T standard H.320 that enables videoconferencing over LANs and other packet-switched networks, as well as video over the Internet.

Източник: Internetworking Terms and Acronyms, June 1999

HBD3

Line code type used on E1 circuits.

Източник: Internetworking Terms and Acronyms, June 1999

HDLC

High-Level Data Link Control Bit-oriented synchronous data link layer protocol developed by ISO. Derived from SDLC, HDLC specifies a data encapsulation method on synchronous serial links using frame characters and checksums.
See also SDLC

Източник: Internetworking Terms and Acronyms, June 1999

HDSL

high-data-rate digital subscriber line One of four DSL technologies. HDSL delivers 1.544 Mbps of bandwidth each way over two copper twisted pairs. Because HDSL provides T1 speed, telephone companies have been using HDSL to provision local access to T1 services whenever possible. The operating range of HDSL is limited to 12,000 feet (3658.5 meters), so signal repeaters are installed to extend the service. HDSL requires two twisted pairs, so it is deployed primarily for PBX network connections, digital loop carrier systems, interexchange POPs, Internet servers, and private data networks.
Compare with ADSL, SDSL, and VDSL

Източник: Internetworking Terms and Acronyms, June 1999

HEC

header error control Algorithm for checking and correcting an error in an ATM cell. Using the fifth octet in the ATMcell header, ATM equipment will check for an error and correct the contents of the header. The check character is calculated using a CRC algorithm allowing a single bit error in the header to be corrected or multiple errors to be detected.

Източник: Internetworking Terms and Acronyms, June 1999

HELLO

Interior routing protocol used principally by NSFnet nodes. HELLO allows particular packet switches to discover minimal delay routes. Not to be confused with the Hello protocol.

Източник: Internetworking Terms and Acronyms, June 1999

HEPnet

High-Energy Physics Network. Research network that originated in the United States, but that has spread to most places involved in high-energy physics. Well-known sites include Argonne National Laboratory, Brookhaven National Laboratory, Lawrence Berkeley Laboratory, and the SLAC.

Източник: Internetworking Terms and Acronyms, June 1999

HFC

hybrid fiber-coaxial. Technology being developed by the cable TV industry to provide two-way, high-speed data access to the home using a combination of fiber optics and traditional coaxial cable.

Източник: Internetworking Terms and Acronyms, June 1999

HIP

HSSI Interface Processor Interface processor on the Cisco 7000 series routers. The HIP provides one HSSI port that supports connections to ATM, SMDS, Frame Relay, or private lines at speeds up to T3 or E3. Cisco Systems Terms and Acronyms

HIPPI

High-Performance Parallel Interface High-performance interface standard defined by ANSI. HIPPI is typically used to connect supercomputers to peripherals and other devices.

Източник: Internetworking Terms and Acronyms, June 1999

HMA

High memory area A+ Certification Training Kit

HPCC

High-Performance Computing and Communications U.S. government funded program advocating advances in computing, communications, and related fields. The HPCC is designed to ensure U.S. leadership in these fields through education, research and development, industry collaboration, and implementation of high-performance technology.
See also the five components of the HPCC: ASTA, BRHR, HPCS, IITA, and NREN.

Източник: Internetworking Terms and Acronyms, June 1999

HPCS

High-Performance Computing Systems Component of the HPCC program designed to ensure U.S. technological leadership in high-performance computing through research and development of computing systems and related software.
See also HPCC

Източник: Internetworking Terms and Acronyms, June 1999

HPR

High-Performance Routing Second-generation routing algorithm for APPN. HPR provides a connectionless layer with nondisruptive routing of sessions around link failures, and a connection-oriented layer with end-to-end flowcontrol, error control, and sequencing.
Compare to ISR. See also APPN

Източник: Internetworking Terms and Acronyms, June 1999

HP-GL

Hewlett-Packard Graphics Language

HP-PCL

Hewlett-Packard Page Control Language

HP-PJL

Hewlett-Packard Printer Job Language

HRR

Horizontal refresh rate A+ Certification Training Kit

HSCI

High-Speed Communications Interface Single-port interface, developed by Cisco, providing full-duplex synchronous serial communications capability at speeds up to 52 Mbps. Cisco Systems Terms and Acronyms

HSRP

Hot Standby Router Protocol Provides high network availability and transparent network topology changes. HSRP creates a Hot Standby router group with a lead router that services all packets sent to the Hot Standby address. The lead router is monitored by other routers in the group, and if it fails, one of these standby routers inherits the lead position and the Hot Standby group address. Cisco Systems Terms and Acronyms

HSSI

High-Speed Serial Interface Network standard for high-speed (up to 52 Mbps) serial connections over WAN links.

Източник: Internetworking Terms and Acronyms, June 1999

HTTP

Hypertext Transfer Protocol The protocol used by Web browsers and Web servers to transfer files, such as text and graphic files.

Източник: Internetworking Terms and Acronyms, June 1999

HTML

Hypertext Markup Language Simple hypertext document formatting language that uses tags to indicate how a given part of a document should be interpreted by a viewing application, such as a Web browser.

Източник: Internetworking Terms and Acronyms, June 1999

IAB

Internet Architecture Board Board of internetwork researchers who discuss issues pertinent to Internet architecture. Responsible for appointing a variety of Internet-related groups such as the IANA, IESG, and IRSG. The IAB is appointed by the trustees of the ISOC.
See also IANA, IESG, IRSG, and ISOC

Източник: Internetworking Terms and Acronyms, June 1999

IAHC

Internet International Ad Hoc Committee Coalition of participants from the broad Internet community, working to satisfy the requirement for enhancements to the Internet’s global DNS. Organizations naming members to the committee include Internet Society (ISOC), Internet Assigned Numbers Authority (IANA), Internet Architecture Board (IAB), Federal Networking Council (FNC), International Telecommunication Union (ITU), International Trademark Association (INTA), and World Intellectual Property Organization (WIPO).

Източник: Internetworking Terms and Acronyms, June 1999

IANA

Internet Assigned Numbers Authority Organization operated under the auspices of the ISOC as a part of the IAB. IANA delegates authority for IP address-space allocation and domain-name assignment to the InterNIC and other organizations. IANAalso maintains a database of assigned protocol identifiers used in the TCP/IP stack, including autonomous system numbers.
See also ICP cell, ISOC, and InterNIC

Източник: Internetworking Terms and Acronyms, June 1999

ICD

International Code Designator One of two ATMaddress formats developed by the ATM Forum for use by private networks. Adapted from the subnetwork model of addressing in which the ATM layer is responsible for mapping network layer addresses to ATM addresses.
Compare with DCC

Източник: Internetworking Terms and Acronyms, June 1999

ICMP

Internet Control Message Protocol Network layer Internet protocol that reports errors and provides other information relevant to IP packet processing. Documented in RFC 792.

Източник: Internetworking Terms and Acronyms, June 1999

ICR

initial cell rate

Източник: Internetworking Terms and Acronyms, June 1999

I-D

Internet-Draft Working documents of the IETF, from its Areas and Working Groups. They are valid for a maximum of 6 months and might be updated, replaced, or obsoleted by other documents at any time. Very often, I-Ds are precursors to RFCs.

Източник: Internetworking Terms and Acronyms, June 1999

IDE

1. Integrated Drive Electronics

2. Integrated Device Electronics A+ Certification Training Kit

IDI

initial domain identifier. Portion of an NSAP or NSAP-format ATM address that specifies the address allocation and administration authority.
See also NSAP

Източник: Internetworking Terms and Acronyms, June 1999

IDN

International Data Number
See X.121

Източник: Internetworking Terms and Acronyms, June 1999

IDP

initial domain part. Part of a CLNS address that contains an authority and format identifier, and a domain identifier.

Източник: Internetworking Terms and Acronyms, June 1999

IDPR

Interdomain Policy Routing. Interdomain routing protocol that dynamically exchanges policies between autonomous systems. IDPR encapsulates interautonomous system traffic and routes it according to the policies of each autonomous system along the path. IDPR is currently an IETF proposal.

Източник: Internetworking Terms and Acronyms, June 1999

IDRP

IS-IS Interdomain Routing Protocol. OSI protocol that specifies how routers communicate with routers in different domains.

Източник: Internetworking Terms and Acronyms, June 1999

IE

information element

Източник: Internetworking Terms and Acronyms, June 1999

IEC

International Electrotechnical Commission. Industry group that writes and distributes standards for electrical products and components.

Източник: Internetworking Terms and Acronyms, June 1999

IEEE

Institute of Electrical and Electronics Engineers Professional organization whose activities include the development of communications and network standards. IEEE LAN standards are the predominant LAN standards today.

Източник: Internetworking Terms and Acronyms, June 1999

IEPG

Internet Engineering Planning Group Group, primarily composed of Internet service operators, whose goal is to promote a globally coordinated Internet operating environment. Membership is open to all.

Източник: Internetworking Terms and Acronyms, June 1999

IESG

Internet Engineering Steering Group Organization, appointed by the IAB, that manages the operation of the IETF.
See also ICP cell and IETF

Източник: Internetworking Terms and Acronyms, June 1999

IETF

Internet Engineering Task Force Task force consisting of over 80 working groups responsible for developing Internet standards. The IETF operates under the auspices of ISOC.
See also ISOC

Източник: Internetworking Terms and Acronyms, June 1999

IFIP

International Federation for Information Processing Research organization that performs OSI prestandardization work. Among other accomplishments, IFIP formalized the original MHS model.
See also MHS

Източник: Internetworking Terms and Acronyms, June 1999

I-frame

Information frame One of three SDLC frame formats.
See also S-frame and U-frame

Източник: Internetworking Terms and Acronyms, June 1999

IGMP

Internet Group Management Protocol Used by IP hosts to report their multicast group memberships to an adjacent multicast router.

Източник: Internetworking Terms and Acronyms, June 1999

IGP

Interior Gateway Protocol Internet protocol used to exchange routing information within an autonomous system. Examples of common Internet IGPs include IGRP, OSPF, and RIP.
See also OSPF and RIP.
See also IGRP (Interior Gateway Routing Protocol)

Източник: Internetworking Terms and Acronyms, June 1999

IGRP

Interior Gateway Routing Protocol IGP developed by Cisco to address the issues associated with routing in large, heterogeneous networks. Compare with Enhanced IGRP. See also IGP, OSPF, and RIP. Cisco Systems Terms and Acronyms

IIH

IS-IS Hello Message sent by all IS-IS systems to maintain adjacencies.
See also IS-IS

Източник: Internetworking Terms and Acronyms, June 1999

IINREN

Interagency Interim National Research and Education Network. Evolving operating network system. Near term research and development activities will provide for the smooth evolution of this networking infrastructure into the future gigabit NREN.

Източник: Internetworking Terms and Acronyms, June 1999

IIOP

Internet Inter-ORB Protocol. Protocol used in the CORBA framework for accessing objects across the Internet.
See also CORBA

Източник: Internetworking Terms and Acronyms, June 1999

IISP

Interim-Interswitch Signaling Protocol. ATM signaling protocol for inter-switch communication using manually configured prefix tables. When a signaling request is received by a switch, the switch checks the destination ATM address against the prefix table and notes the port with the longest prefix match. It then forwards the signaling request across that port using UNI procedures. IISP is an interim solution until PNNI Phase 1 is completed. Formerly known as PNNI Phase 0. Contrast with Dynamic IISP.

Източник: Internetworking Terms and Acronyms, June 1999

IITA

Information Infrastructure Technology and Applications Component of the HPCC program intended to ensure U.S. leadership in the development of advanced information technologies.
See also HPCC

Източник: Internetworking Terms and Acronyms, June 1999

IKE

Internet Key Exchange

Източник: Internetworking Terms and Acronyms, June 1999

ILMI

Interim Local Management Interface. Specification developed by the ATM Forum for incorporating network-management capabilities into the ATM UNI.

Източник: Internetworking Terms and Acronyms, June 1999

IMA

inverse multiplexing over ATM Standard protocol defined by the ATM Forum in 1997.

Източник: Internetworking Terms and Acronyms, June 1999

IMAP

Internet Message Access Protocol Method of accessing e-mail or bulletin board messages kept on a mail server that can be shared. IMAP permits client electronic mail applications to access remote message stores as if they were local without actually transferring the message.

Източник: Internetworking Terms and Acronyms, June 1999

IMHO

“In My Humble Opinion.” One of many short-form phrases seen in e-mail messages, newsgroups, and so on.

Източник: Internetworking Terms and Acronyms, June 1999

IMP

interface message processor. Old name for ARPANET packet switches.
See also ARPANET

Източник: Internetworking Terms and Acronyms, June 1999

IMT

Inter-Machine Trunk

Източник: Internetworking Terms and Acronyms, June 1999

IN/AIN

Intelligent Network/Advanced Intelligent Network

Източник: Internetworking Terms and Acronyms, June 1999

INA

Information Networking Architecture. Bellcore object-oriented architecture for the management of ATM and SONET equipment and services in an operating company environment.

Източник: Internetworking Terms and Acronyms, June 1999

INASoft

Bellcore implementation of INA.
See also INA

Източник: Internetworking Terms and Acronyms, June 1999

INB

Install Busy
Entity has just been created but has not been commanded In-Service or Out-of-Service yet.

Източник: Internetworking Terms and Acronyms, June 1999

INE

Intelligent Network Element Network element that can be provisioned from a remote OSS.

Източник: Internetworking Terms and Acronyms, June 1999

INOC

Internet Network Operations Center
BBN group that in the early days of the Internet monitored and controlled the Internet core gateways (routers). INOC no longer exists in this form.

Източник: Internetworking Terms and Acronyms, June 1999

INTAP

Interoperability Technology Association for Information Processing. Technical organization that has the official charter to develop Japanese OSI profiles and conformance tests.

Източник: Internetworking Terms and Acronyms, June 1999

Internet

Largest global internetwork, connecting tens of thousands of networks worldwide and having a “culture” that focuses on research and standardization based on real-life use. Many leading-edge network technologies come from the Internet community. The Internet evolved in part from ARPANET. At one time, called the DARPA Internet. Not to be confused with the general term internet.
See also ARPANET

Източник: Internetworking Terms and Acronyms, June 1999

InterNIC

Organization that serves the Internet community by supplying user assistance, documentation, training, registration service for Internet domain names, and other services. Formerly called NIC.

Източник: Internetworking Terms and Acronyms, June 1999

I/O

input/output

Източник: Internetworking Terms and Acronyms, June 1999

IOC

independent operating company Independently owned company providing local telephone services to residential and business customers in a geographic area not served by an RBOC.

Източник: Internetworking Terms and Acronyms, June 1999

IOCC

I/O channel controller

Източник: Internetworking Terms and Acronyms, June 1999

IONL

Internal Organization of the Network Layer OSI standard for the detailed architecture of the network layer. Basically, it partitions the network layer into subnetworks interconnected by convergence protocols (equivalent to internet working protocols), creating what the Internet community calls a catenet or internet.

Източник: Internetworking Terms and Acronyms, June 1999

IOR

Input/output read wire

Вижте също : IOW A+ Certification Training Kit

IOS

Cisco IOS Cisco system software that provides common functionality, scalability, and security for all products under the CiscoFusion architecture. Cisco IOS allows centralized, integrated, and automated installation and management of internetworks, while ensuring support for a wide variety of protocols, media, services, and platforms. Cisco Systems Terms and Acronyms

IOW

Input/output write wire

Вижте също : IOR A+ Certification Training Kit

IP

Internet Protocol Network layer protocol in the TCP/IP stack offering a connectionless internetwork service. IP provides features for addressing, type-of-service specification, fragmentation and reassembly, and security. Defined in RFC 791.

Източник: Internetworking Terms and Acronyms, June 1999

IPC

interprocess communication

Източник: Internetworking Terms and Acronyms, June 1999

IPCP

IP Control Protocol. Protocol that establishes and configures IP over PPP.
See also IP and PPP

Източник: Internetworking Terms and Acronyms, June 1999

IPng

See IPv6

Източник: Internetworking Terms and Acronyms, June 1999

IPv6

IP version 6
Replacement for the current version of IP (version 4). IPv6 includes support for flow ID in the packet header, which can be used to identify flows. Formerly called IPng (next generation).

Източник: Internetworking Terms and Acronyms, June 1999

IPSO

IP Security Option. U.S. government specification that defines an optional field in the IP packet header that defines hierarchical packet security levels on a per interface basis.

Източник: Internetworking Terms and Acronyms, June 1999

IPX

Internetwork Packet Exchange NetWare network layer (Layer 3) protocol used for transferring data from servers to workstations. IPX is similar to IP and XNS.

Източник: Internetworking Terms and Acronyms, June 1999

IPXCP

IPX Control Protocol. Protocol that establishes and configures IPX over PPP.
See also IPX and PPP

Източник: Internetworking Terms and Acronyms, June 1999

IPXWAN

IPX wide-area network Protocol that negotiates end-to-end options for new links. When a link comes up, the first IPX packets sent across are IPXWAN packets negotiating the options for the link. When the IPXWAN options are successfully determined, normal IPX transmission begins. Defined by RFC 1362.

Източник: Internetworking Terms and Acronyms, June 1999

IR

Internet Registry IR was delegated the responsibility of network address and autonomuous system identifiers from the IANA, which has the discretionary authority to delegate portions of its responsibility.

Източник: Internetworking Terms and Acronyms, June 1999

IRB

integrated routing and bridging Integrated Services Digital Network (ISDN) User Part. An upper-layer application supported by SS7 for connection set up and tear down.

Източник: Internetworking Terms and Acronyms, June 1999

IRC

Internet Relay Chat World-wide “party line” protocol that allows one to converse with others in real time. IRC is structured as a network of servers, each of which accepts connections from client programs, one per user.

Източник: Internetworking Terms and Acronyms, June 1999

IRDP

ICMP Router Discovery Protocol. Protocol that enables a host to determine the address of a router that it can use as a default gateway. Similar to ES-IS, but used with IP.
See also ES-IS

Източник: Internetworking Terms and Acronyms, June 1999

IRN

intermediate routing node In SNA, a subarea node with intermediate routing capability.

Източник: Internetworking Terms and Acronyms, June 1999

IRQ

Interrupt request A+ Certification Training Kit

IRSG

Internet Research Steering Group Group that is part of the IAB and oversees the activities of the IRTF.
See also ICP cell and IRTF

Източник: Internetworking Terms and Acronyms, June 1999

IRTF

Internet Research Task Force Community of network experts that considers Internet-related research topics. The IRTF is governed by the IRSG and is considered a subsidiary of the IAB.
See also ICP cell and IRSG

Източник: Internetworking Terms and Acronyms, June 1999

IS

1. intermediate system. Routing node in an OSI network. 2. [Telecommunications] In-Service. Entity is fully operational and capable of providing service to a requesting entity.

Източник: Internetworking Terms and Acronyms, June 1999

ISA

Industry-Standard Architecture 16-bit bus used for Intel-based personal computers.
See also EISA

Източник: Internetworking Terms and Acronyms, June 1999

ISDN

Integrated Services Digital Network Communication protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other source traffic.
See also BISDN, BRI, N-ISDN, and PRI

Източник: Internetworking Terms and Acronyms, June 1999

IS-IS

Intermediate System-to-Intermediate System OSI link-state hierarchical routing protocol based on DECnet Phase V routing, whereby ISs (routers) exchange routing information based on a single metric, to determine network topology.
Compare with Integrated IS-IS
See also ES-IS and OSPF

Източник: Internetworking Terms and Acronyms, June 1999

ISL

Inter-Switch Link Cisco-proprietary protocol that maintains VLAN information as traffic flows between switches and routers. Cisco Systems Terms and Acronyms

ISM

internetwork status monitor

Източник: Internetworking Terms and Acronyms, June 1999

ISO

International Organization for Standardization International organization that is responsible for a wide range of standards, including those relevant to networking. ISO developed the OSI reference model, a popular networking reference model.

Източник: Internetworking Terms and Acronyms, June 1999

ISOC

Internet Society International nonprofit organization, founded in 1992, that coordinates the evolution and use of the Internet. In addition, ISOC delegates authority to other groups related to the Internet, such as the IAB. ISOC is headquartered in Reston, Virginia, (United States).

Източник: Internetworking Terms and Acronyms, June 1999

ISODE

ISO development environment Large set of libraries and utilities used to develop upper-layer OSI protocols and applications.

Източник: Internetworking Terms and Acronyms, June 1999

ISP

Internet service provider Company that provides Internet access to other companies and individuals.

Източник: Internetworking Terms and Acronyms, June 1999

ISR

Intermediate Session Routing Initial routing algorithm used in APPN. ISR provides node-to-node connection-oriented routing. Network outages cause sessions to fail because ISR cannot provide nondisruptive rerouting around a failure. ISR was replaced by HPR.
Compare with HPR
See also APPN

Източник: Internetworking Terms and Acronyms, June 1999

ISSI

Inter-Switching System Interface Standard interface between SMDS switches.

Източник: Internetworking Terms and Acronyms, June 1999

ISUP

ISDN User Part

Източник: Internetworking Terms and Acronyms, June 1999

ITU-T

International Telecommunication Union Telecommunication Standardization Sector. International body that develops worldwide standards for telecommunications technologies. The ITU-T carries out the functions of the former CCITT.
See also CCITT

Източник: Internetworking Terms and Acronyms, June 1999

IVR

interactive voice response Term used to describe systems that provide information in the form of recorded messages over telephone lines in response to user input in the form of spoken words or more commonly DTMF signaling. Examples include banks that allow you to check your balance from any telephone and automated stock quote systems.

Източник: Internetworking Terms and Acronyms, June 1999

IXC

inter-exchange carrier. Common carrier providing long distance connectivity between LATAs. The three major IXCs are AT&T, MCI, and Sprint, but several hundred IXCs offer long distance service in the United States.

Източник: Internetworking Terms and Acronyms, June 1999

JANET

Joint Academic Network X.25 WAN connecting university and research institutions in the United Kingdom.

Източник: Internetworking Terms and Acronyms, June 1999

Java

Object-oriented programming language developed at Sun Microsystems to solve a number of problems in modern programming practice. The Java language is used extensively on World-Wide Web, particularly for applets.

Източник: Internetworking Terms and Acronyms, June 1999

JDBC

Java Database Connectivity Java API that enables Java programs to execute SQL statements. This allows Java programs to interact with any SQL-compliant database. Since nearly all relational database management systems (DBMSs) support SQL, and because Java itself runs on most platforms, JDBC makes it possible to write a single database application that can run on different platforms and interact with different DBMSs. JDBC is similar to ODBC, but is designed specifically for Java programs, whereas ODBC is language-independent. JDBC was developed by JavaSoft, a subsidiary of Sun Microsystems.
See ODBC

Източник: Internetworking Terms and Acronyms, June 1999

jitter

Analog communication line distortion caused by the variation of a signal from its reference timing positions. Jitter can cause data loss, particularly at high speeds.

Източник: Internetworking Terms and Acronyms, June 1999

JPEG

Joint Photographics Expert Group Graphic file format that was adopted as a standard by the ITU-T and the ISO. JPEG is most often used to compress still images using DCT analysis.

Източник: Internetworking Terms and Acronyms, June 1999

JUNET

Japan UNIX Network
Nationwide, noncommercial network in Japan, designed to promote communication between Japanese and other researchers.

Източник: Internetworking Terms and Acronyms, June 1999

JvNCnet

John von Neumann Computer Network. Regional network, owned and operated by Global Enterprise Services, Inc., composed of T1 and slower serial links providing midlevel networking services to sites in the Northeastern United States.

Източник: Internetworking Terms and Acronyms, June 1999

KA9Q

Popular implementation of TCP/IP and associated protocols for amateur packet radio systems.

Източник: Internetworking Terms and Acronyms, June 1999

KB

1. KB - kilobyte Approximately 1,000 bytes. 2. Kb - kilobit Approximately 1,000 bits.

Източник: Internetworking Terms and Acronyms, June 1999

kBps

kilobytes per second

Източник: Internetworking Terms and Acronyms, June 1999

kbps

kilobits per second

Източник: Internetworking Terms and Acronyms, June 1999

Kerberos

Developing standard for authenticating network users. Kerberos offers two key benefits: it functions in a multivendor network, and it does not transmit passwords over the network.

Източник: Internetworking Terms and Acronyms, June 1999

Kermit

Popular file-transfer and terminal-emulation program.

Източник: Internetworking Terms and Acronyms, June 1999

kVA

kilovoltampere.

LAN

local-area network High-speed, low-error data network covering a relatively small geographic area (up to a few thousand meters). LANs connect workstations, peripherals, terminals, and other devices in a single building or other geographically limited area. LAN standards specify cabling and signaling at the physical and data link layers of the OSI model. Ethernet, FDDI, and Token Ring are widely used LAN technologies.
Compare with MAN and WAN

Източник: Internetworking Terms and Acronyms, June 1999

LANE

LAN emulation Technology that allows an ATM network to function as a LAN backbone. The ATM network must provide multicast and broadcast support, address mapping (MAC-to-ATM), SVC management, and a usable packet format. LANE also defines Ethernet and Token Ring ELANs.
See also ELAN

Източник: Internetworking Terms and Acronyms, June 1999

LAPB

Link Access Procedure, Balanced. Data link layer protocol in the X.25 protocol stack. LAPB is a bit-oriented protocol derived from HDLC.
See also HDLC and X.25

Източник: Internetworking Terms and Acronyms, June 1999

LAPD

Link Access Procedure on the D channel ISDN data link layer protocol for the D channel. LAPD was derived from the LAPB protocol and is designed primarily to satisfy the signaling requirements of ISDN basic access. Defined by ITU-T Recommendations Q.920 and Q.921.

Източник: Internetworking Terms and Acronyms, June 1999

LAPM

Link Access Procedure for Modems ARQ used by modems implementing the V.42 protocol for error correction.
See also ARQ and V.42

Източник: Internetworking Terms and Acronyms, June 1999

laser

light amplification by stimulated emission of radiation Analog transmission device in which a suitable active material is excited by an external stimulus to produce a narrow beam of coherent light that can be modulated into pulses to carry data. Networks based on laser technology are sometimes run over SONET.

Източник: Internetworking Terms and Acronyms, June 1999

LAT

local-area transport
A network virtual terminal protocol developed by Digital Equipment Corporation.

Източник: Internetworking Terms and Acronyms, June 1999

LATA

local access and transport area Geographic telephone dialing area serviced by a single local telephone company. Calls within LATAs are called local calls. There are well over 100 LATAs in the United States.

Източник: Internetworking Terms and Acronyms, June 1999

LBA

Logical Block Addressing A+ Certification Training Kit

LCI

logical channel identifier
See VCN

Източник: Internetworking Terms and Acronyms, June 1999

LCN

logical channel number
See VCN

Източник: Internetworking Terms and Acronyms, June 1999

LCP

link control protocol Protocol that establishes, configures, and tests data-link connections for use by PPP.
See also PPP

Източник: Internetworking Terms and Acronyms, June 1999

LCV

line code violation Occurrence of a BPV or EXZ error event.

Източник: Internetworking Terms and Acronyms, June 1999

LDAP

Lightweight Directory Access Protocol Protocol that provides access for management and browser applications that provide read/write interactive access to the X.500 Directory.

Източник: Internetworking Terms and Acronyms, June 1999

LDCELP

low-delay CELP CELP voice compression algorithm providing 16 Kbps, or 4:1 compression. Standardized in ITU-T Recommendation G.728.

Източник: Internetworking Terms and Acronyms, June 1999

LE_ARP

LAN Emulation Address Resolution Protocol Protocol that provides the ATM address that corresponds to a MAC address.

Източник: Internetworking Terms and Acronyms, June 1999

LEC

1. LAN Emulation Client
Entity in an end system that performs data forwarding, address resolution, and other control functions for a single ES within a single ELAN. An LEC also provides a standard LAN service interface to any higher-layer entity that interfaces to the LEC. Each LEC is identified by a unique ATM address, and is associated with one or more MAC addresses reachable through that ATM address. See also ELAN and LES. 2. local exchange carrier
Local or regional telephone company that owns and operates a telephone network and the customer lines that connect to it.

Източник: Internetworking Terms and Acronyms, June 1999

LECS

LAN Emulation Configuration Server Entity that assigns individual LANE clients to particular ELANs by directing them to the LES that corresponds to the ELAN. There is logically one LECS per administrative domain, and this serves all ELANs within that domain.
See also ELAN

Източник: Internetworking Terms and Acronyms, June 1999

LED

light emitting diode Semiconductor device that emits light produced by converting electrical energy. Status lights on hardware devices are typically LEDs.

Източник: Internetworking Terms and Acronyms, June 1999

LES

LAN Emulation Server Entity that implements the control function for a particular ELAN. There is only one logical LES per ELAN, and it is identified by a unique ATM address.
See also ELAN

Източник: Internetworking Terms and Acronyms, June 1999

LGN

logical group node The node that represents its peer group in the peer group’s parent peer group.

Източник: Internetworking Terms and Acronyms, June 1999

LIM

Lotus/Intel/Microsoft A+ Certification Training Kit

LIR

Local Internet Registry

Описание:
Localen Internet Register. Negova cel e da se grizhi za obezpechavaneto na klientite s IP adresni prostranstva na localno nivo i da osyshtestviava adresna regulacia. V syshtoto vreme LIR e i pylnomoshtnik za registrirane na in-addr.arpa domainite prilezhashti kym razdadenite mrezhovi prostranstva (nai- malko za mrezhi ot class "C", t.e. /24).

Източник : Веселин Колев

LIS

logical IP subnet A group of IP nodes (such as hosts and routers) that connects to a single ATM network and belongs to the same IP subnet.

Източник: Internetworking Terms and Acronyms, June 1999

LLAP

LocalTalk Link Access Protocol Link-level protocol that manages node-to-node delivery of data on a LocalTalk network. LLAP manages bus access, provides a node-addressing mechanism, and controls data transmission and reception, ensuring packet length and integrity.

Източник: Internetworking Terms and Acronyms, June 1999

LLC

Logical Link Control
Higher of the two data link layer sublayers defined by the IEEE. The LLC sublayer handles error control, flow control, framing, and MAC-sublayer addressing. The most prevalent LLC protocol is IEEE 802.2, which includes both connectionless and connection-oriented variants.
See also MAC

Източник: Internetworking Terms and Acronyms, June 1999

LLC2

Logical Link Control, type 2. Connection-oriented OSI LLC-sublayer protocol. See also LLC.

LMI

Local Management Interface Set of enhancements to the basic Frame Relay specification. LMI includes support for a keepalive mechanism, which verifies that data is flowing; a multicast mechanism, which provides the network server with its local DLCI and the multicast DLCI; global addressing, which gives DLCIs global rather than local significance in Frame Relay networks; and a status mechanism, which provides an on-going status report on the DLCIs known to the switch. Known as LMT in ANSI terminology.

LM/X

LAN Manager for UNIX Monitors LAN devices in UNIX environments.

LNNI

LAN Emulation Network-to-Network Interface Supports communication between the server components within a single ELAN. Phase 1 LANE protocols do not allow for the standard support of multiple LESs or BUSs within an ELAN. Phase 2 addresses these limitations.

LNM

LAN Network Manager SRB and Token Ring management package provided by IBM. Typically running on a PC, it monitors SRB and Token Ring devices, and can pass alerts up to NetView.

LPD

line printer daemon Protocol used to send print jobs between UNIX systems.

LPT

Line printer A+ Certification Training Kit

LSA

link-state advertisement Broadcast packet used by link-state protocols that contains information about neighbors and path costs. LSAs are used by the receiving routers to maintain their routing tables. Sometimes called a LSP.

LSP

link-state packet. See LSA

LU

logical unit Primary component of SNA, an NAU that enables end users to communicate with each other and gain access to SNA network resources.

LUNI

LAN Emulation User-to-Network Interface The ATM Forum standard for LAN emulation on ATM networks. Defines the interface between the LEC and the LAN Emulation Server components. See also BUS, LES, and LECS

LVM


Logical Volume Management

The ability to make multiple physical disk storage devices appear to be a single large disk volume, incorporating redundant storage and error checking such that the failure of any one of the physical volumes still allows all the data to be recovered.

MAC

1.Media Access Control. Lower of the two sublayers of the data link layer defined by the IEEE. The MAC sublayer handles access to shared media, such as whether token passing or contention will be used. See also data-link layer and LLC. 2.MAC address Standardized data link layer address that is required for every port or device that connects to a LAN. Other devices in the network use these addresses to locate specific ports in the network and to create and update routing tables and data structures. MAC addresses are 6 bytes long and are controlled by the IEEE. Also known as a hardware address, MAC-layer address, and physical address. Compare with network address.

MacIP

Network layer protocol that encapsulates IP packets in DDP packets for transmission over AppleTalk. MacIP also provides proxy ARP services. See also DDP and proxy ARP.

MAE

metropolitan access exchange One of a number of Internet exchange points. Examples include MAE West and MAE East. See also CIX, FIX, and GIX.

MAN

metropolitan-area network Network that spans a metropolitan area. Generally, a MAN spans a larger geographic area than a LAN, but a smaller geographic area than a WAN. Compare with LAN and WAN.

MAP

Manufacturing Automation Protocol Network architecture created by General Motors to meet the specific needs of the factory floor. MAP specifies a token-passing LAN similar to IEEE 802.4. See also IEEE 802.4.

MARS

Multicast Address Resolution Server Mechanism for supporting IP multicast. A MARS serves a group of nodes (known as a cluster); each node in the cluster is configured with the ATM address of the MARS. The MARS supports multicast through multicast messages of overlaid point-to-multipoint connections or through multicast servers.

Martian

Humorous term applied to packets that turn up unexpectedly on the wrong network because of bogus routing entries. Also used as a name for a packet that has an altogether bogus (nonregistered or ill-formed) Internet address.

MAU

media attachment unit Device used in Ethernet and IEEE 802.3 networks that provides the interface between the AUI port of a station and the common medium of the Ethernet. The MAU, which can be built into a station or can be a separate device, performs physical layer functions including the conversion of digital data from the Ethernet interface, collision detection, and injection of bits onto the network. Sometimes referred to as a media access unit, also abbreviated MAU, or as a transceiver. In Token Ring, a MAU is known as a multistation access unit and is usually abbreviated MSAU to avoid confusion. See also AUI and MSAU

MB

megabyte. Approximately 1,000,000 bytes.

Mb

megabit. Approximately 1,000,000 bits.

MBS

maximum burst size In an ATMsignaling message, burst tolerance is conveyed through the MBS, which is coded as a number of cells. The burst tolerance together with the SCR and the GCRA determine the MBS that can be transmitted at the peak rate and still be in conformance with the GCRA. See also SCP and GCRA

MBONE

multicast backbone Multicast backbone of the Internet. MBONE is a virtual multicast network composed of multicast LANs and the point-to-point tunnels that interconnect them.

Mbps

megabits per second.

MCA

micro channel architecture Bus interface commonly used in PCs and some UNIX workstations and servers.

MCC

Memory controller chip A+ Certification Training Kit

MCDV

maximum cell delay variation In an ATM network, the maximum two-point CDV objective across a link or node for the specified service category. One of four link metrics exchanged using PTSPs to determine the available resources of an ATM network. There is one MCDV value for each traffic class. See also CDV and PTSP

MCLR

maximum cell loss ratio In an ATM network, the maximum ratio of cells that do not successfully transit a link or node compared with the total number of cells that arrive at the link or node. One of four link metrics exchanged using PTSPs to determine the available resources of an ATM network. The MCLR applies to cells in the CBR and VBR traffic classes whose CLP bit is set to zero. See also CBR, CLP, PTSP, and VBR.

MCNS

Multimedia Cable Network System Partners Ltd. Consortium of cable companies providing service to the majority of homes in the United States and Canada. This consortium drives a standard with the goal of having interoperable cable modems.

MCR

minimum cell rate

Parameter defined by the ATMForum for ATMtraffic management. MCR is defined only for ABR transmissions, and specifies the minimum value for the ACR. See also ABR (available bit rate), ACOM, and PCR

MCTD

maximum cell transfer delay In an ATM network, the sum of the MCDV and the fixed delay component across the link or node. One of four link metrics exchanged using PTSPs to determine the available resources of an ATM network. There is one MCTD value for each traffic class. See also MCDV and PTSP

MD

mediation device. Device that provides protocol translation and concentration of telemetry information originating from multiple network elements and transport to an OSS. See also OSS

MD5

Message Digest 5 Algorithm used for message authentication in SNMP v.2. MD5 verifies the integrity of the communication, authenticates the origin, and checks for timeliness. See also SNMP2

MDA

Monochrome Display Adapter A+ Certification Training Kit

MDL

The TransPath Message Definition Language High-level language used to specify protocols and protocol conversion operations on the TransPath.

MDN

message disposition notification Message returned to the originator of an e-mail message indicating that the e-mail message has been opened. Specifications for MDN are described in RFC 2298.

MDRAM

Multibank DRAM A+ Certification Training Kit

MFM

Modified frequency modulation A+ Certification Training Kit

MFT

multiflex trunk module

MHS

message handling system ITU-T X.400 recommendations that provide message handling services for communications between distributed applications. NetWare MHS is a different (though similar) entity that also provides message-handling services.See also IFIP

MHz

Megahertz A+ Certification Training Kit

MIB

Management Information Base Database of network management information that is used and maintained by a network management protocol such as SNMP or CMIP. The value of a MIB object can be changed or retrieved using SNMP or CMIP commands, usually through a GUI network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.

MIC

media interface connector FDDI de facto standard connector.

MICA

1. Modem ISDN channel aggregation Modem module and card used in the Cisco AS5300 universal access servers. A MICA modem provides an interface between an incoming or outgoing digital call and an Integrated Services Digital Network (ISDN) telephone line; the call does not have to be converted to analog, as it does with a conventional modem and an analog telephone line. Each line can accommodate, or aggregate, up to 24 (T1) or 30 (E1)calls. 2. Multiservice IOS Channel Aggregation Technology that enables the simultaneous support of remote-access users through both analog modems and ISDN devices.

MID

message identifier In ATM, used to identify ATM cells that carry segments from the same higher-layer packet.

MILNET

Military Network Unclassified portion of the DDN. Operated and maintained by the DISA. See also DDN and DISA

MIME

Multipurpose Internet Mail Extension MIME. Sstandard for transmitting non-text data (or data that cannot be represented in plain ASCII code) in Internet mail, such as binary, foreign language text (such as Russian or Chinese), audio, or video data. MIME is defined in RFC 2045.

MIP

MultiChannel Interface Processor Interface processor on the Cisco 7000 series routers that provides up to two channelized T1 or E1 connections via serial cables to a CSU. The two controllers on the MIP can each provide up to 24 T1 or 30 E1 channel-groups, with each channel-group presented to the system as a serial interface that can be configured individually. Cisco Systems Terms and Acronyms

mips

millions of instructions per second Number of instructions executed by a processor per second.

MIX

multiservice interchange

MLP

Multilink PPP Method of splitting, recombining, and sequencing datagrams across multiple logical data links.

MMF

multimode fiber

MML

TransPath Man-Machine Language

MMoIP

Multimedia Mail over IP

MMP

Multichassis Multilink PPP Extends MLP support across multiple routers and access servers. MMP enables multiple routers and access servers to operate as a single, large dial-up pool, with a single network address and ISDN access number. MMP correctly handles packet fragmenting and reassembly when a user connection is split between two physical access devices.

modem

modulator-demodulator Device that converts digital and analog signals. At the source, a modem converts digital signals to a form suitable for transmission over analog communication facilities. At the destination, the analog signals are returned to their digital form. Modems allow data to be transmitted over voice-grade telephone lines.

MOP

Maintenance Operation Protocol Digital Equipment Corporation protocol that provides a way to perform primitive maintenance operations on DECnet systems. For example, MOP can be used to download a system image to a diskless station.

MOS

Metal-Oxide Semiconductor A+ Certification Training Kit

Mosaic

Public-domain WWW browser, developed at the NCSA. See also browser

MOSPF

Multicast OSPF Intradomain multicast routing protocol used in OSPF networks. Extensions are applied to the base OSPF unicast protocol to support IP multicast routing.

MPEG

Motion Picture Experts Group Standard for compressing video. MPEG1 is a bit stream standard for compressed video and audio optimized to fit into a bandwidth of 1.5 Mbps. MPEG2 is intended for higher quality video-on-demand applications and runs at data rates between 4 and 9 Mbps. MPEG4 is a low-bit-rate compression algorithm intended for 64-kbps connections.

MPLS

Multiprotocol Label Switching Emerging industry standard upon which tag switching is based.

MPOA

Multiprotocol over ATM ATM Forum standardization effort specifying how existing and future network-layer protocols such as IP, IPv6, AppleTalk, and IPX run over an ATM network with directly attached hosts, routers, and multilayer LAN switches.

MPPC

Microsoft point to point compression

MPPE

Microsoft point to point encryption

MQI

Message Queuing Interface International standard API that provides functionality similar to that of the RPC interface. In contrast to RPC, MQI is implemented strictly at the application layer. See also RPC

MSAU

multistation access unit Wiring concentrator to which all end stations in a Token Ring network connect. The MSAUprovides an interface between these devices and the Token Ring interface of a router. Sometimes abbreviated MAU.

MSD

Microsoft Diagnostics A+ Certification Training Kit

MSO

multiple service operator Cable service provider that also provides other services such as data and/or voice telephony.

MTA

1. Message Transfer Agent. OSI application process used to store and forward messages in the X.400 Message Handling System. Equivalent to Internet mail agent. 2. Mail Transfer Agent. Software that implements SMTP and provides storage for mail messages to be forwarded or delivered to a local user. MTAs implement SMTP (RFC 821).

MTBF

meantime between failures

MTU

maximum transmission unit Maximum packet size, in bytes, that a particular interface can handle.

MUD

multi-user dungeon Adventure, role playing games, or simulations played on the Internet. Players interact in real time and can change the “world” in the game as they play it. Most MUDs are based on the Telnet protocol.

NACS

NetWare Asynchronous Communication Services Novell software that supports Novell’s AIO and NASI programming interfaces. NACS promotes the sharing of communications resources such as modems, asynchronous hosts, and X.25 network services.

NADF

North American Directory Forum Collection of organizations that offer, or plan to offer, public directory services in North America, based on the CCITT X.500 Recommendations.

NADN

nearest active downstream neighbor In Token Ring or IEEE 802.5 networks, the closest downstream network device from any given device that is still active.

NAK

negative acknowledgment Response sent from a receiving device to a sending device indicating that the information received contained errors. Compare to acknowledgment.

NANOG

North American Network Operator’s Group Primary forum for information exchange among U.S. exchange point participants, Internet service providers, and end users.

NANP

North American Numbering Plan

NAP

network access point Location for interconnection of Internet service providers in the United States for the exchange of packets.

NARP

NBMA Address Resolution Protocol Functional subset of NHRP that returns only the address mappings of nodes that are directly connected to the NBMA network. Compare with NHRP.

NAS

network access server Cisco platform (or collection of platforms such as an AccessPath system which interfaces between the packet world (e.g. the Internet) and the circuit world (e.g. the PSTN). (See access device.)

NAS

network access server A NASI NetWare Asynchronous Support Interface.

NAT

Network Address Translation

Mechanism for reducing the need for globally unique IP addresses. NAT allows an organization with addresses that are not globally unique to connect to the Internet by translating those addresses into globally routable address space. Also known as Network Address Translator.

NAU

network addressable unit SNA term for an addressable entity. Examples include LUs, PUs, and SSCPs. NAUs generally provide upper-level network services. Compare with path control network.

NAUN

nearest active upstream neighbor In Token Ring or IEEE 802.5 networks, the closest upstream network device from any given device that is still active.

NBFCP

NetBIOS Frames Control Protocol Protocol that establishes and configures NetBIOS over PPP. See also NetBIOS and PPP

NBMA

nonbroadcast multiaccess Term describing a multiaccess network that either does not support broadcasting (such as X.25) or in which broadcasting is not feasible (for example, an SMDS broadcast group or an extended Ethernet that is too large). See also multiaccess network.

NBNS

NetBIOS Name Service

NBP

Name Binding Protocol AppleTalk transport-level protocol that translates a character string name into the DDP address of the corresponding socket client. NBP enables AppleTalk protocols to understand user-defined zones and device names by providing and maintaining translation tables that map names to their corresponding socket addresses.

NBS

National Bureau of Standards Organization that was part of the U.S. Department of Commerce. Now known as NIST. See also NIST

NCIA

native client interface architecture SNA applications-access architecture, developed by Cisco, that combines the full functionality of native SNA interfaces at both the host and client with the flexibility of leveraging TCP/IP backbones. NCIA encapsulates SNA traffic on a client PC or workstation, thereby providing direct TCP/IP access while preserving the native SNA interface at the end-user level. In many networks, this capability obviates the need for a standalone gateway and can provide flexible TCP/IP access while preserving the native SNA interface to the host. Cisco Systems Terms and Acronyms

NCP

1. Network Control Program. In SNA, a program that routes and controls the flow of data between a communications controller (in which it resides) and other network resources. 2. Network Control Protocol. Series of protocols for establishing and configuring different network layer protocols, such as for AppleTalk over PPP. See also PPP.

NCSA

National Center for Supercomputing Applications.

NDIS

Network Driver Interface Specification Microsoft specification for a generic, hardware-and protocol-independent device driver for NICs.

NE

network element In OSS, a single piece of telecommunications equipment used to perform a function or service integral to the underlying network.

NEARNET

Regional network in NewEngland (United States) that links Boston University, Harvard University, and MIT. Now part of BBN Planet. See also BBN Planet.

NEBS

Network Equipment Building Systems In OSS, the Bellcore requirement for equipment deployed in a central office environment. Covers spatial, hardware, crafts person interface, thermal, fire resistance, handling and transportation, earthquake and vibration, airborne contaminants, grounding, acoustical noise, illumination, EMC, and ESD requirements.

NEMS

Network Element Management Server.

NET

1.network entity title. Network addresses, defined by the ISO network architecture, and used in CLNS-based networks. 2.Short for Network

NetBEUI

NetBIOS Extended User Interface Enhanced version of the NetBIOS protocol used by network operating systems such as LAN Manager, LAN Server, Windows for Workgroups, and Windows NT. NetBEUI formalizes the transport frame and adds additional functions. NetBEUI implements the OSI LLC2 protocol. See also LLC2 and OSI

NetBIOS

Network Basic Input/Output System API used by applications on an IBM LAN to request services from lower-level network processes. These services might include session establishment and termination, and information transfer.

NetFlow

Network flow is defined as a unidirectional sequence of packets between given source and destination endpoints. Network flows are highly granular: flow endpoints are identified both by IP address as well as by transport layer application port numbers. (NetFlow also uses IP Protocol, ToS and the input interface port to uniquely identify flows.) Conventional network layer switching handles incoming packets independently, with separate serial tasks for switching, security, services and traffic measurements applied to each packet. With NetFlow switching, this process is applied only to the first packet of a flow. Information from the first packet is used to build an entry in the NetFlow cache. Subsequent packets in the flow are handled via a single streamlined task that handles switching, services, and data collection concurrently.

netiquette

A pun on “etiquette” referring to proper behavior on a network.

NETscout

See NETscout in the “Cisco Systems Terms and Acronyms” section.

NetView

IBM network management architecture and related applications. NetView is a VTAM application used for managing mainframes in SNA networks. See also VTAM

NetWare

Popular distributed NOS developed by Novell. Provides transparent remote file access and numerous other distributed network services.

NFS

Network File System As commonly used, a distributed file system protocol suite developed by Sun Microsystems that allows remote file access across a network. In actuality, NFS is simply one protocol in the suite. NFS protocols include NFS, RPC, XDR, and others. These protocols are part of a larger architecture that Sun refers to as ONC. See also ONC

NHRP

Next Hop Resolution Protocol Protocol used by routers to dynamically discover the MAC address of other routers and hosts connected to a NBMA network. These systems can then directly communicate without requiring traffic to use an intermediate hop, increasing performance in ATM, Frame Relay, SMDS, and X.25 environments.

NHS

Next Hop Server Server defined by the NHRP protocol that maintains next-hop resolution cache tables containing the IP-to-ATMaddress mappings of associated nodes and nodes that are reachable through routers served by the NHS.

NIC

1. network interface card Board that provides network communication capabilities to and from a computer system. Also called an adapter. See also AUI. 2. Network Information Center. Organization whose functions have been assumed by the InterNIC. See InterNIC

NIS

Network Information Service Protocol developed by Sun Microsystems for the administration of network-wide databases. The service essentially uses two programs: one for finding a NIS server and one for accessing the NIS databases.

N-ISDN

Narrowband ISDN Communication standards developed by the ITU-T for baseband networks. Based on 64-kbps B channels and 16- or 64-kbps D channels. Contrast with BISDN. See also BRI, ISDN, and PRI

NIST

National Institute of Standards and Technology U.S. government organization that supports and catalogs a variety of standards. Formerly the NBS. See also NBS

NLM

NetWare Loadable Module Individual program that can be loaded into memory and function as part of the NetWare NOS.

NLSP

NetWare Link Services Protocol Link-state routing protocol based on IS-IS. See also IS-IS

NMA

Network Management and Analysis Bellcore OSS providing alarm surveillance and performance monitoring of intelligent network elements.

NMP

Network Management Processor Processor module on the Catalyst 5000 switch used to control and monitor the switch. Cisco Systems Terms and Acronyms

NMS

network management system System responsible for managing at least part of a network. An NMS is generally a reasonably powerful and well-equipped computer such as an engineering workstation. NMSs communicate with agents to help keep track of network statistics and resources.

NMVT

network management vector transport SNA message consisting of a series of vectors conveying network management specific information.

NN

network node SNA intermediate node that provides connectivity, directory services, route selection, intermediate session routing, data transport, and network management services to LEN nodes and ENs. The NN contains a CP that manages the resources of both the NN itself and those of the ENs and LEN nodes in its domain. NNs provide intermediate routing services by implementing the APPN PU 2.1 extensions. Compare with EN. See also CP

NNI

1. Network-to-Network Interface. ATM Forum standard that defines the interface between two ATMswitches that are both located in a private network or are both located in a public network. The interface between a public switch and private one is defined by the UNI standard. Also, the standard interface between two Frame Relay switches meeting the same criteria. Compare with UNI. 2. network node interface.

NOA

nature of address.

NOC

network operations center Organization responsible for maintaining a network.

NOS

network operating system Generic term used to refer to what are really distributed file systems. Examples of NOSs include LAN Manager, NetWare, NFS, and VINES.

NPI

number plan identification.

NREN

National Research and Education Network Component of the HPCC program designed to ensure U.S. technical leadership in computer communications through research and development efforts in state-of-the-art telecommunications and networking technologies. See also HPCC

NRM

normal response mode HDLC mode for use on links with one primary station and one or more secondary stations. In this mode, secondary stations can transmit only if they first receive a poll from the primary station.

NRZ

nonreturn to zero Signals that maintain constant voltage levels with no signal transitions (no return to a zero-voltage level) during a bit interval. Compare with NRZI

NRZI

nonreturn to zero inverted Signals that maintain constant voltage levels with no signal transitions (no return to a zero-voltage level), but interpret the presence of data at the beginning of a bit interval as a signal transition and the absence of data as no transition. Compare with NRZ.

NSAP

network service access point Network addresses, as specified by ISO. An NSAP is the point at which OSI Network Service is made available to a transport layer (Layer 4) entity.

NSF

National Science Foundation U.S. government agency that funds scientific research in the United States. The now-defunct NSFNET was funded by the NSF. See also NSFNET.

NSFNET

National Science Foundation Network Large network that was controlled by the NSF and provided networking services in support of education and research in the United States, from 1986 to 1995. NSFNET is no longer in service.

NSP

Network Service Point Cisco

NT-1

network termination 1 In ISDN, a device that provides the interface between customer premises equipment and central office switching equipment.

NTP

Network Time Protocol Protocol built on top of TCP that assures accurate local time-keeping with reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing distributed clocks within milliseconds over long time periods.

NTRI

NCP/Token Ring Interconnection Function used by ACF/NCP to support Token Ring-attached SNA devices. NTRI also provides translation from Token Ring-attached SNA devices (PUs) to switched (dial-up) devices.

NTSC

National Television Standards Committee A+ Certification Training Kit

NVE

network-visible entity Resource that is addressable through a network. Typically, an NVE is a socket client for a service available in a node.

NVRAM

nonvolatile RAM RAM that retains its contents when a unit is powered off.

NUMA

Non-Uniform Memory Access

A method of configuring a cluster of microprocessors in a multiprocessing system so that they can share memory locally, improving performance and the ability of the system to be expanded.

NYSERNet

Network in New York (United States) with a T1 backbone connecting NSF, many universities, and several commercial concerns.

OAM&P

operations administration maintenance and provisioning.

OARnet

Ohio Academic Resources Network Internet service provider that connects a number of U.S. sites, including the Ohio supercomputer center in Columbus, Ohio.

OC

optical carrier Series of physical protocols (OC-1, OC-2, OC-3, and so forth), defined for SONET optical signal transmissions. OC signal levels put STS frames onto multimode fiber-optic line at a variety of speeds. The base rate is 51.84 Mbps (OC-1); each signal level thereafter operates at a speed divisible by that number (thus, OC-3 runs at 155.52 Mbps). See also SONET, STS-1, and STS-3c

OCC

originating call control

OCLC

Online Computer Library Catalog. Nonprofit membership organization offering computer-based services to libraries, educational organizations, and their users.

octet

8 bits In networking, the term octet is often used (rather than byte) because some machine architectures employ bytes that are not 8 bits long.

ODA

Open Document Architecture ISO standard that specifies how documents are represented and transmitted electronically. Formerly called Office Document Architecture.

ODBC

Open DataBase Connectivity Standard application programming interface for accessing data in both relational and nonrelational database management systems. Using this application programming interface, database applications can access data stored in database management systems on a variety of computers even if each database management system uses a different data storage format and programming interface. ODBC is based on the call level interface specification of the X/Open SQL Access Group and was developed by Digitial Equipment Corporation, Lotus, Microsoft, and Sybase. Contrast with JDBC.

ODI

Open Data-Link Interface Novell specification providing a standardized interface for NICs (network interface cards) that allows multiple protocols to use a single NIC. See also NIC

OIM

OSI Internet Management. Group tasked with specifying ways in which OSI network management protocols can be used to manage TCP/IP networks.

OIR

online insertion and removal Feature that permits the addition, replacement, or removal of cards without interrupting the system power, entering console commands, or causing other software or interfaces to shut down. Sometimes called hot swapping or power-on servicing.

OLE

Object linking and embedding A+ Certification Training Kit

OMG

Object Management Group

ONC

Open Network Computing Distributed applications architecture designed by Sun Microsystems, currently controlled by a consortium led by Sun. The NFS protocols are part of ONC. See also NFS

OOS

1. Out-of-Service. 2. Telecommunications: Out-of-Service signaling.

OPC

own point code Point code of the Cisco SC2200 signaling controller.

OPS/INE

Operations Provisioning System/lntelligent Network Element Bellcore OSS that provides provisioning services for intelligent network elements. See also OSS

OSF

Open Software Foundation Group responsible for the Distributed Computing Environment (DCE) and the Distributed Management Environment (DME). See DCE

OSI

Open System Interconnection International standardization program created by ISO and ITU-T to develop standards for data networking that facilitate multivendor

OSINET

International association designed to promote OSI in vendor architectures.

OSPF

Open Shortest Path First Link-state, hierarchical IGP routing algorithm proposed as a successor to RIP in the Internet community. OSPF features include least-cost routing, multipath routing, and load balancing. OSPF was derived from an early version of the IS-IS protocol. See also IGP, IS-IS, and RIP. See also Enhanced IGRP and IGRP (Interior Gateway Routing Protocol) in the “Cisco Systems Terms and Acronyms” section.

OSS

1.Operations Support System Network management system supporting a specific management function, such as alarm surveillance and provisioning, in a carrier network. Many OSSs are large centralized systems running on mainframes or minicomputers. Common OSSs used within an RBOC include NMA, OPS/INE, and TIRKS. 2. Open Sound System

OUI

Organizational Unique Identifier. 3 octets assigned by the IEEE in a block of 48-bit LAN addresses.

PABX

private automatic branch exchange Telephone switch for use inside a corporation. PABX is the preferred term in Europe, while PBX is used in the United States.

PAD

packet assembler/disassembler. Device used to connect simple devices (like character-mode terminals) that do not support the full functionality of a particular protocol to a network. PADs buffer data and assemble and disassemble packets sent to such end devices.

PAM

1. pulse amplitude modulation Modulation scheme where the modulating wave is caused to modulate the amplitude of a pulse stream. Compare with AM and FM. See also modulation 2.Pluggable Authentication Modules Linux-PAM Is a system of libraries that handle the authentication tasks of applications (services) on the system. Източник : pam man page

PAP

Password Authentication Protocol Authentication protocol that allows PPP peers to authenticate one another. The remote router attempting to connect to the local router is required to send an authentication request. Unlike CHAP, PAP passes the password and host name or username in the clear (unencrypted). PAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or access server then determines if that user is allowed access. PAP is supported only on PPP lines. Compare with CHAP.

PARC

Palo Alto Research Center Research and development center operated by XEROX. A number of widely-used technologies were originally conceived at PARC, including the first personal computers and LANs.

PBX

private branch exchange. Digital or analog telephone switchboard located on the subscriber premises and used to connect private and public telephone networks.

PC

Personal Computer

PCI

1. protocol control information Control information added to user data to comprise an OSI packet. The OSI equivalent of the term header. See also header.

2. Peripheral Component Interconnect A+ Certification Training Kit

PCM

pulse code modulation Transmission of analog information in digital form through sampling and encoding the samples with a fixed number of bits.

PCR

peak cell rate Parameter defined by the ATM Forum for ATM traffic management. In CBR transmissions, PCR determines how often data samples are sent. In ABR transmissions, PCR determines the maximum value of the ACR. See also ABR (available bit rate), ACOM, and CBR

PCS

1. Personal Communications Service. Advanced network architecture that provides personal, terminal, and service mobility. In the United States, PCS spectrum has been allocated for broadband, narrowband, and unlicensed services. 2. port concentrator switch.

PDC

Primary Domain Contoller

PDI

Post DMA-IRQ card A+ Certification Training Kit

PDL

Page-description language A+ Certification Training Kit

PDN

public data network Network operated either by a government (as in Europe) or by a private concern to provide computer communications to the public, usually for a fee. PDNs enable small organizations to create a WAN without all the equipment costs of long-distance circuits.

PDU

protocol data unit OSI term for packet. See also BPDU and packet.

PEM

privacy enhanced mail Internet e-mail that provides confidentiality, authentication, and message integrity using various encryption methods. Not widely deployed in the Internet.

P/F

poll/final bit Bit in bit-synchronous data link layer protocols that indicates the function of a frame. If the frame is a command, a 1 in this bit indicates a poll. If the frame is a response, a 1 in this bit indicates that the current frame is the last frame in the response.

PGA

1. Pin grid array

2. Professional Graphics Adapter A+ Certification Training Kit

PGL

peer group leader In ATM, a node in a peer group that performs the functions of the LGN. Peer group leaders exchange PTSPs with peer nodes in the parent peer group to inform those nodes of the peer group’s attributes and reachability and to propagate information about the parent group and the parent group’s parents to the nodes in the peer group. See also peer group and PTSP

PGP

Pretty Good Privacy Public-key encryption application that allows secure file and message exchanges. There is some controversy over the development and use of this application, in part due to U.S. national security concerns.

PHY

1. physical sublayer. One of two sublayers of the FDDI physical layer. See also PMD. 2. physical layer. In ATM, the physical layer provides for the transmission of cells over a physical medium that connects two ATM devices. The PHY is comprised of two sublayers: PMD and TC. See also PMD and TC.

PHYSNET

Physics Network Group of many DECnet-based physics research networks, including HEPnet. See also HEPnet

PIM

Protocol Independent Multicast Multicast routing architecture that allows the addition of IP multicast routing on existing IP networks. PIM is unicast routing protocol independent and can be operated in two modes: dense and sparse. See also PIM dense mode and PIM sparse mode.

ping

packet internet groper ICMP echo message and its reply. Often used in IP networks to test the reachability of a network device.

PINX

private integrated services network exchange. A PBX or key system which, in a BRI voice application, uses QSIG signaling.

PIO

Programmed Input/Output A+ Certification Training Kit

PKI

public key infrastructure

PLAR

private line, automatic ringdown Leased voice circuit that connects two single endpoints together. When either telephone handset is taken off-hook, the remote telephone automatically rings.

PLCC

Plastic leadless chip carrier A+ Certification Training Kit

PLCP

physical layer convergence procedure Specification that maps ATMcells into physical media, such as T3 or E3, and defines certain management information.

PLIM

physical layer interface module Interface that allows the AIP (ATM Interface Processor) to a variety of physical layers, including TAXI and SONET multimode fiber-optic cable, SDH/SONET single-mode fiber cable, and E3 coaxial cable. Cisco Systems Terms and Acronyms

PLP

packet level protocol Network layer protocol in the X.25 protocol stack. Sometimes called X.25 Level 3 and X.25 Protocol. See also X.25

PLSP

PNNI link state packets

PLU

Primary Logical Unit The LU that is initiating a session with another LU. See also LU

PM

Preventive maintenance A+ Certification Training Kit

PMD

physical medium dependent Sublayer of the FDDI physical layer that interfaces directly with the physical medium and performs the most basic bit transmission functions of the network. See also PHY

PNNI

1. Private Network-Network Interface. ATM Forum specification for distributing topology information between switches and clusters of switches that is used to compute paths through the network. The specification is based on well-known link-state routing techniques and includes a mechanism for automatic configuration in networks in which the address structure reflects the topology. 2. Private Network Node Interface. ATM Forum specification for signaling to establish point-to-point and point-to-multipoint connections across an ATM network. The protocol is based on the ATMForum UNI specification with additional mechanisms for source routing, crankback, and alternate routing of call setup requests.

POET

packet over E3/T3

POL

Provisioning Object Library

POM

Provisioning Object Manager

POP

1. point of presence. In OSS, a physical location where an interexchange carrier installed equipment to interconnect with an LEC (local exchange carrier). 2. Post Office Protocol. Protocol that client e-mail applications use to retrieve mail from a mail server.

POSI

Promoting Conference for OSI Group of executives from the six major Japanese computer manufacturers and Nippon Telephone and Telegraph that sets policies and commits resources to promote OSI.

POST

power-on self test Set of hardware diagnostics that runs on a hardware device when that device is powered up.

POTS

plain old telephone service. See PSTN

PPP

Point-to-Point Protocol Successor to SLIP that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits. Whereas SLIP was designed to work with IP, PPP was designed to work with several network layer protocols, such as IP, IPX, and ARA. PPP also has builtin security mechanisms, such as CHAP and PAP. PPP relies on two protocols: LCP and NCP. See also CHAP, LCP, NCP, PAP, and SLIP

PPTP

Point-to-Point Tunneling Protocol

PQ

priority queuing

PQFP

Plastic Quad Flat Pack

PRI

Primary Rate Interface ISDN interface to primary rate access. Primary rate access consists of a single 64-Kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data. Compare with BRI See also BISDN, ISDN, and N-ISDN

PRMD

Private Management Domain X.400 Message Handling System private organization mail system (for example, NASAmail).

PROM

programmable read-only memory ROM that can be programmed using special equipment. PROMs can be programmed only once. Compare with EPROM

PSDN

packet-switched data network. See PSN

PSE

packet switch exchange Essentially, a switch. The term PSE is generally used in reference to a switch in an X.25 packet-switch. See also switch

PSN

packet-switched network Network that uses packet-switching technology for data transfer. Sometimes called a PSDN. See packet switching.

PSTN

Public Switched Telephone Network General term referring to the variety of telephone networks and services in place worldwide. Sometimes called POTS

PTI

payload type identifier 3-bit descriptor in the ATM cell header indicating the type of payload that the cell contains. Payload types include user and management cells; one combination indicates that the cell is the last cell of an AAL5 frame.

PTSE

PNNI topology state element. Collection of PNNI information that is flooded among all logical nodes within a peer group. See also peer group and PNNI.

PTSP

PNNI topology state packet Type of PNNI routing packet used to exchange reachability and resource information among ATM switches to ensure that a connection request is routed to the destination along a path that has a high probability of meeting the requested QoS. Typically, PTSPs include bidirectional information about the transit behavior of particular nodes (based on entry and exit ports) and current internal state. See also PNNI and QoS

PTT

Post, Telephone, and Telegraph Government agency that provides telephone services. PTTs exist in most areas outside North America and provide both local and long-distance telephone services.

PU

physical unit SNA component that manages and monitors the resources of a node, as requested by an SSCP. There is one PU per node.

PUP

PARC Universal Protocol Protocol similar to IP developed at PARC.

PVC

permanent virtual circuit or connection Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection. Compare with SVC

PVP

permanent virtual path Virtual path that consists of PVCs. See also PVC and virtual path.

Q.2931

ITU-T specification, based on Q.931, for establishing, maintaining, and clearing network connections at the B-ISDN user-network interface. The UNI 3.1 specification is based on Q.2931. See also Q.931 and UNI

Q.922A

ITU-T specification for Frame Relay encapsulation.

Q.931

ITU-T specification for signaling to establish, maintain, and clear ISDN network connections. See also Q.93B

Q.931

ITU standard that describes ISDN signaling. The H.225.0 standard uses a variant of Q.931 to establish and disconnect H.323 sessions.

Q.93B

ITU-T specification for signaling to establish, maintain, and clear BISDN network connections. An evolution of ITU-T recommendation Q.931. See also Q.931.

QAM

quadrature amplitude modulation Method of modulating digital signals onto a radio-frequency carrier signal involving both amplitude and phase coding. QAM is a modulation scheme mostly used in the downstream direction (QAM-64, QAM-256).

QLLC

Qualified Logical Link Control Data link layer protocol defined by IBM that allows SNA data to be transported across X.25 networks.

QoS

quality of service Measure of performance for a transmission system that reflects its transmission quality and service availability.

QPSK

Quadrature Phase-Shift Keying a method of modulating digital signals onto a radio-frequency carrier signal using four phase states to code two digital bits.

QRSS

quasi-random signal sequence: a test pattern widely used to simulate voice signals.

QSIG

Q (point of the ISDN model) Signaling. Signaling standard. Common channel signaling protocol based on ISDN Q.931 standards and used by many digital PBXs.

QUIPU

Pioneering software package developed to study the OSI Directory and provide extensive pilot capabilities.

QWP

query with permission

RACE

Research on Advanced Communications in Europe Project sponsored by the EC for the development of broadband networking capabilities.

RAID

Redundant array of independent disks A+ Certification Training Kit

RAM

Random access memory A+ Certification Training Kit

RAS

1. Registration, Admission, and Status protocol Protocol used in the H.323 protocol suite for discovering and interacting with a Gatekeeper. 2. Row Add Select

RDI

remote defect identification In ATM, when the physical layer detects loss of signal or cell synchronization, RDI cells are used to report a VPC/VCC failure. RDI cells are sent upstream by a VPC/VCC endpoint to notify the source VPC/VCC endpoint of the downstream failure.

RADIUS

Remote Dial-In User Service Database for authenticating modem and ISDN connections and for tracking connection time.

RAM

random-access memory Volatile memory that can be read and written by a microprocessor.

RARE

Rйseaux Associйs pour la Recherche Europйenne Association of European universities and research centers designed to promote an advanced telecommunications infrastructure in the European scientific community. RARE merged with EARN to form TERENA. See also EARN and TERENA.

RARP

Reverse Address Resolution Protocol Protocol in the TCP/IP stack that provides a method for finding IP addresses based on MAC addresses. Compare with ARP

RBHC

regional Bell holding company One of seven regional telephone companies formed by the breakup of AT&T. RBHCs differ from RBOCs in that RBHCs cross state boundaries.

RBOC

regional Bell operating company Seven regional telephone companies formed by the breakup of AT&T. RBOCs differ from RBHCs in that RBOCs do not cross state boundaries.

RD

Request Disconnect

RF

radio frequency Generic term referring to frequencies that correspond to radio transmissions. Cable TV and broadband networks use RF technology.

RFC

Request For Comments Document series used as the primary means for communicating information about the Internet. Some RFCs are designated by the IAB as Internet standards. Most RFCs document protocol specifications such as Telnet and FTP, but some are humorous or historical. RFCs are available online from numerous sources.

RFI

radio frequency interference Radio frequencies that create noise that interferes with information being transmitted across unshielded copper cable.

RFS

Remote File System Distributed file system, similar to NFS, developed by AT&T and distributed with their UNIX System V operating system.

RFP

request for proposal

RHC

regional holding company

RIF

Routing Information Field Field in the IEEE 802.5 header that is used by a source-route bridge to determine through which Token Ring network segments a packet must transit. A RIF is made up of ring and bridge numbers as well as other information.

RII

Routing Information Identifier Bit used by SRT bridges to distinguish between frames that should be transparently bridged and frames that should be passed to the SRB module for handling.

RIM

Request Initialization Mode

RIP

Routing Information Protocol IGP supplied with UNIX BSD systems. The most common IGP in the Internet. RIP uses hop count as a routing metric. See also hop count, IGP, and OSPF. See also Enhanced IGRP and IGRP (Interior Gateway Routing Protocol) in the “Cisco Systems Terms and Acronyms” section.

RIPE

Rйseaux IP Europйennes Group formed to coordinate and promote TCP/IP-based networks in Europe.

RISC

reduced instruction set computing

RJE

remote job entry Application that is batch-oriented, as opposed to interactive. In RJE environments, jobs are submitted to a computing facility, and output is received later.

rlogin

remote login Terminal emulation program, similar to Telnet, offered in most UNIX implementations.

RLL

Run-length limited A+ Certification Training Kit

RLM

Redundant Link Manager

RM

resource management Management of critical resources in an ATM network. Two critical resources are buffer space and trunk bandwidth. Provisioning can be used to allocate network resources in order to separate traffic flows according to service characteristics.

RMON

remote monitoring MIB agent specification described in RFC 1271 that defines functions for the remote monitoring of networked devices. The RMON specification provides numerous monitoring, problem detection, and reporting capabilities.

ROLC

routing over large clouds Working group in IETF created to analyze and propose solutions to problems that arise when performing IP routing over large, shared media networks such as ATM, Frame Relay, SMDS, and X.25.

ROM

read-only memory Nonvolatile memory that can be read, but not written, by the microprocessor.

ROSE

Remote Operations Service Element OSI RPC mechanism used by various OSI network application protocols.

RP

Route Processor Processor module in the Cisco 7000 series routers that contains the CPU, system software, and most of the memory components that are used in the router. Sometimes called a supervisory processor. Cisco Systems Terms and Acronyms

RPC

remote-procedure call Technological foundation of client-server computing. RPCs are procedure calls that are built or specified by clients and executed on servers, with the results returned over the network to the clients. See also client/server computing.

RPF

Reverse Path Forwarding Multicasting technique in which a multicast datagram is forwarded out of all but the receiving interface if the receiving interface is the one used to forward unicast datagrams to the source of the multicast datagram.

RR

relative rate In ATM, one of the congestion feedback modes provided by ABR service. In RR mode, switches set a bit in forward and backward RM cells to indicate congestion. See also ABR and RLM

RS-232

Popular physical layer interface. Now known as EIA/TIA-232. See EIA/TIA-232

RS-422

Balanced electrical implementation of EIA/TIA-449 for high-speed data transmission. Now referred to collectively with RS-423 as EIA-530. See also EIA-530 and RS-423

RS-423

Unbalanced electrical implementation of EIA/TIA-449 for EIA/TIA-232 compatibility. Now referred to collectively with RS-422 as EIA-530. See also EIA-530 and RS-422

RS-449

Popular physical layer interface. Now known as EIA/TIA-449. See EIA/TIA-449.

RSA

Rivest, Shamir, and Adelman the inventors of the technique. Public-key cryptographic system which may be used for encryption and authentication.

rsh

remote shell protocol Protocol that allows a user to execute commands on a remote system without having to log in to the system. For example, rsh can be used to remotely examine the status of a number of access servers without connecting to each communication server, executing the command, and then disconnecting from the communication server.

RSM

Route Switch Module

RSP

Route/Switch Processor Processor module in the Cisco 7500 series routers that integrates the functions of the RP and the SP. See also RP and SP. Cisco Systems Terms and Acronyms

RSRB

remote source-route bridging SRB over WAN links. See also SRB

RSUP

Reliable SAP Update Protocol Bandwidth-saving protocol developed by Cisco for propagating services information. RSUP allows routers to reliably send standard Novell SAP packets only when the routers detect a change in advertised services. RSUP can transport network information either in conjunction with or independently of the Enhanced IGRP routing function for IPX. Cisco Systems Terms and Acronyms

RSVP

Resource Reservation Protocol Protocol that supports the reservation of resources across an IP network. Applications running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so forth) of the packet streams they want to receive. RSVP depends on IPv6. Also known as Resource Reservation Setup Protocol. See also IPv6

RTCP

RTP Control Protocol Protocol that monitors the QOS of an IPv6 RTP connection and conveys information about the on-going session. See also RTP (Real-Time Transport Protocol).

RTFM

read the fantastic manual Acronym often used when someone asks a simple or common question.

RTMP

Routing Table Maintenance Protocol Apple Computer’s proprietary routing protocol. RTMP establishes and maintains the routing information that is required to route datagrams from any source socket to any destination socket in an AppleTalk network. Using RTMP, routers dynamically maintain routing tables to reflect changes in topology. RTMP was derived from RIP. See also RIP (Routing Table Protocol).

RTP

1. Routing Table Protocol. VINES routing protocol based on RIP. Distributes network topology information and aids VINES servers in finding neighboring clients, servers, and routers. Uses delay as a routing metric. See also SRTP. 2. Rapid Transport Protocol. Provides pacing and error recovery for APPN data as it crosses the APPN network. With RTP, error recovery and flow control are done end-to-end rather than at every node. RTP prevents congestion rather than reacts to it. 3. Real-Time Transport Protocol. One of the IPv6 protocols. RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over multicast or unicast network services. RTP provides services such as payload type identification, sequence numbering, timestamping, and delivery monitoring to real-time applications.

RTS

Request To Send EIA/TIA-232 control signal that requests a data transmission on a communications line.

RTSC

read the source code

RTSP

Real Time Streaming Protocol Enables the controlled delivery of real-time data, such as audio and video. Sources of data can include both live data feeds, such live audio and video, and stored content, such as pre-recorded events. RTSP is designed to work with established protocols, such as RTP and HTTP.

RTT

round-trip time Time required for a network communication to travel from the source to the destination and back. RTT includes the time required for the destination to process the message from the source and generate a reply. RTT is used by some routing algorithms to aid in calculating optimal routes.

RU

request/response unit Request and response messages exchanged between NAUs in an SNA network.

RUDP

Reliable User Data Protocol

RVI

required visual inspection

SAC

single-attached concentrator FDDI or CDDI concentrator that connects to the network by being cascaded from the master port of another FDDI or CDDI concentrator.

SAP

1. service access point. Field defined by the IEEE 802.2 specification that is part of an address specification. Thus, the destination plus the DSAP define the recipient of a packet. The same applies to the SSAP. See also DSAP and SSAP. 2. Service Advertising Protocol. IPX protocol that provides a means of informing network clients, via routers and servers, of available network resources and services. See also IPX.

SAR

segmentation and reassembly One of the two sublayers of the AAL CPCS, responsible for dividing (at the source) and reassembling (at the destination) the PDUs passed from the CS. The SAR sublayer takes the PDUs processed by the CS and, after dividing them into 48-byte pieces of payload data, passes them to the ATM layer for further processing. See also AAL, ATM layer, CPCS, CS, and SSCS

SAS

1. single attachment station. Device attached only to the primary ring of an FDDI ring. Also known as a Class B station. Compare with DAS. See also FDDI. 2. statically assigned socket. Socket that is permanently reserved for use by a designated process. In an AppleTalk network, SASs are numbered 1 to 127; they are reserved for use by specific socket clients and for low-level built-in network services.

SBus

Bus technology used in Sun SPARC-based workstations and servers. The SBus specification was adopted by the IEEE as a new bus standard.

SCCP

Signaling Connection Control Part. Trillium software that supports routing and translation and management functions and data transfer without logical signaling connections.

SCP

1. Service Control Point An element of an SS7-based Intelligent Network which performs various service functions, such as number translation, call setup and teardown, etc. 2. Secure Copy

SCR

sustainable cell rate Parameter defined by the ATM Forum for ATM traffic management. For VBR connections, SCR determines the long-term average cell rate that can be transmitted. See also VBR

SCSI

Small Computer System Interface A+ Certification Training Kit

SCTE

serial clock transmit external Timing signal that DTE echoes to DCE to maintain clocking. SCTE is designed to compensate for clock phase shift on long cables. When the DCE device uses SCTE instead of its internal clock to sample data from the DTE, it is better able to sample the data without error even if there is a phase shift in the cable. See also phase shift.

SDH

Synchronous Digital Hierarchy European standard that defines a set of rate and format standards that are transmitted using optical signals over fiber. SDH is similar to SONET, with a basic SDH rate of 155.52 Mbps, designated at STM-1. See also SONET and STM-1.

SDLC

Synchronous Data Link Control SNA data link layer communications protocol. SDLC is a bit-oriented, full-duplex serial protocol that has spawned numerous similar protocols, including HDLC and LAPB. See also HDLC and LAPB

SDLLC

SDLC Logical Link Control Cisco IOS feature that performs translation between SDLC and IEEE 802.2 type 2.

SDRAM

Synchronous dynamic random access memory A+ Certification Training Kit

SDSL

single-line digital subscriber line One of four DSL technologies. SDSL delivers1.544 Mbps both downstream and upstream over a single copper twisted pair. The use of a single twisted pair limits the operating range of SDSL to 10,000 feet (3048.8 meters). Compare with ADSL, HDSL, and VDSL.

SDSU

SMDS DSU DSU for access to SMDS via HSSIs and other serial interfaces.

SDU

service data unit Unit of information from an upper-layer protocol that defines a service request to a lower-layer protocol.

SEAL

simple and efficient AAL Scheme used by AAL5 in which the SAR sublayer segments CS PDUs without adding additional fields. See also AAL, AAL5, CS, and SAR

SET

Secure Electronic Transactions SET specification developed to allow for secure credit card and off-line debit card (check card) transactions over the World-Wide Web.

SF

Super Frame Common framing type used on T1 circuits. SF consists of 12 frames of 192 bits each, with the 193rd bit providing error checking and other functions. SF is superseded by ESF, but is still widely used. Also called D4 framing. See also ESF

S-frame

Supervisory frame One of three SDLC frame formats. See also I-frame and U-frame.

SGCP

Simple Gateway Control Protocol Controls Voice over IP gateways by an external call control element (called a call-agent). This has been adapted to allow SGCP to control switch ATM Circuit Emulation Service circuits (called endpoints in SGCP). The resulting system (call-agents and gateways) allows for the call-agent to engage in Common Channel Signalling (CCS) over a 64-Kbps CES circuit, governing the interconnection of bearer channels on the CES interface.

SGML

Standardized Generalized Markup Language International standard for the definition of system-independent, device-independent methods of representing text in electronic form.

SGMP

Simple Gateway Monitoring Protocol Network management protocol that was considered for Internet standardization and later evolved into SNMP. Documented in RFC 1028. See also SNMP

SGRAM

Synchronous Graphics RAM A+ Certification Training Kit

SID

Service ID: a number that defines (at the MAC sublayer) a particular mapping between a cable modem (CM) and the CMTS. The SID is used for the purpose of upstream bandwidth allocation and class-of-service management.

SIM

Set Initialization Mode

SIMM

Single inline memory module A+ Certification Training Kit

SIP

1. SMDS Interface Protocol Used in communications between CPE and SMDS network equipment. Allows the CPE to use SMDS service for high-speed WAN internetworking. Based on the IEEE 802.6 DQDB standard. See also DQDB. 2. serial interface processor 3. session initiation protocol

SIPP

Single inline pin package A+ Certification Training Kit

SLAC

Stanford Linear Accelerator Center

SLC

Signaling link code Code that identifies a linkset

SLIP

Serial Line Internet Protocol Standard protocol for point-to-point serial connections using a variation of TCP/IP. Predecessor of PPP. See also CSI and PPP

SMAC

source MAC MAC address specified in the Source Address field of a packet. Compare with DMAC. See also MAC address

SMB

Server Message Block File-system protocol used in LAN manager and similar NOSs to package data and exchange information with other systems.

SMDS

Switched Multimegabit Data Service High-speed, packet-switched, datagram-based WAN networking technology offered by the telephone companies. See also CBDS.

SMI

Structure of Management Information Document (RFC 1155) specifying rules used to define managed objects in the MIB. See also MIB

SMM

System Management Mode A+ Certification Training Kit

SMO

state machine object

SMP

Symmetric Multi-Processing

The ability to allocate work in a computer among multiple processor chips in such a way that all are as efficiently utilized as possible, leading to completion of programs in the shortest possible time.

SMRP

Simple Multicast Routing Protocol Specialized multicast network protocol for routing multimedia data streams on enterprise networks. SMRP works in conjunction with multicast extensions to the AppleTalk protocol.

SMT

Station Management ANSI FDDI specification that defines how ring stations are managed.

SMTP

Simple Mail Transfer Protocol Internet protocol providing e-mail services.

SNA

Systems Network Architecture Large, complex, feature-rich network architecture developed in the 1970s by IBM. Similar in some respects to the OSI reference model, but with a number of differences. SNA is essentially composed of seven layers. See data flow control layer, data-link control layer, path control layer, physical control layer, presentation services layer, transaction services layer, and transmission control layer.

SNADS

SNA Distribution Services Consists of a set of SNA transaction programs that interconnect and cooperate to provide asynchronous distribution of information between end users. One of three SNA transaction services. See also DDM and DIA

SNAP

Subnetwork Access Protocol Internet protocol that operates between a network entity in the subnetwork and a network entity in the end system. SNAP specifies a standard method of encapsulating IP datagrams and ARP messages on IEEE networks. The SNAP entity in the end system makes use of the services of the subnetwork and performs three key functions: data transfer, connection management, and QoS selection.

SNI

1. Subscriber Network Interface. Interface for SMDS-based networks that connects CPE and an SMDS switch. See also UNI. 2. SNA Network Interconnection. IBM gateway connecting multiple SNA networks.

SNMP

Simple Network Management Protocol Network management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security. See also SGMP and SNMP2

SNP

sequence number protection

SNPA

subnetwork point of attachment Data link layer address (such as an Ethernet address, X.25 address, or Frame Relay DLCI address). SNPA addresses are used to configure a CLNS route for an interface.

SNRM

Set Normal Response

SNRME

Set Normal Response. Mode Exchange.

socket

1. Software structure operating as a communications end point within a network device. 2. Addressable entity within a node connected to an AppleTalk network; sockets are owned by software processes known as socket clients. AppleTalk sockets are divided into two groups: SASs, which are reserved for clients such as AppleTalk core protocols, and DASs, which are assigned dynamically by DDP upon request from clients in the node. An AppleTalk socket is similar in concept to a TCP/IP port.

SOHO

small office, home office Networking solutions and access technologies for offices that are not directly connected to large corporate networks.

SONET

Synchronous Optical Network High-speed (up to 2.5 Gbps) synchronous network specification developed by Bellcore and designed to run on optical fiber. STS-1 is the basic building block of SONET. Approved as an international standard in 1988. See also SDH, STS-1, and STS-3c.

SP

1. Signaling Processor, Signaling Point. 2. Switch Processor Cisco 7000-series processor module that acts as the administrator for all CxBus activities. Sometimes called ciscoBus controller. See also CxBus. Cisco Systems Terms and Acronyms

SPA

Software Publishers Association A+ Certification Training Kit

SPAG

Standards Promotion and Application Group Group of European OSI manufacturers that chooses option subsets and publishes these in the “Guide to the Use of Standards” (GUS).

spam

Term used to describe unsolicited e-mail or newsgroup posts, often in the form of commercial announcements. The act of sending a spam is called, naturally spamming.

SPAN

1.Full-duplex digital transmission line between two digital facilities. 2.Switched Port Analyzer Feature of the Catalyst 5000 switch that extends the monitoring abilities of existing network analyzers into a switched Ethernet environment. SPAN mirrors the traffic at one switched segment onto a predefined SPAN port. A network analyzer attached to the SPAN port can monitor traffic from any of the other Catalyst switched ports.

SPF

shortest path first algorithm Routing algorithm that iterates on length of path to determine a shortest-path spanning tree. Commonly used in link-state routing algorithms. Sometimes called Dijkstra’s algorithm. See also link-state routing algorithm.

SPID

service profile identifier Number that some service providers use to define the services to which an ISDN device subscribes. The ISDN device uses the SPID when accessing the switch that initializes the connection to a service provider.

SPP

Sequenced Packet Protocol Provides reliable, connection-based, flow-controlled packet transmission on behalf of client processes. Part of the XNS protocol suite.

SPX

Sequenced Packet Exchange Reliable, connection-oriented protocol that supplements the datagram service provided by network layer (Layer 3) protocols. Novell derived this commonly used NetWare transport protocol from the SPP of the XNS protocol suite.

SQE

signal quality error Transmission sent by a transceiver back to the controller to let the controller know whether the collision circuitry is functional. Also called heartbeat.

SQL

Structured Query Language International standard language for defining and accessing relational databases.

SRAM

Static Random Acces Memory
Описание :

Статичните SRAM памети са изградени на базата на запомнящ елемент - тригер. Този елемент помни съдържанието си до изключване на захранването или до запис на нови данни. Съдържанието е независимо от времето. SRAM паметите не се нуждаят от непрекъснато опресняване както DRAM.

Сравнете с : DRAM

SRB

source-route bridging Method of bridging originated by IBM and popular in Token Ring networks. In an SRB network, the entire route to a destination is predetermined, in real time, prior to the sending of data to the destination. Contrast with transparent bridging.

SRP

spatial reuse protocol

SRT

source-route transparent bridging IBM bridging scheme that merges the two most prevalent bridging strategies: SRB and transparent bridging. SRT employs both technologies in one device to satisfy the needs of all ENs. No translation between bridging protocols is necessary. Compare with SR/TLB

SR/TLB

source-route translational bridging Method of bridging where source-route stations can communicate with transparent bridge stations with the help of an intermediate bridge that translates between the two bridge protocols. Compare with SRT

SRTP

Sequenced Routing Update Protocol Protocol that assists VINES servers in finding neighboring clients, servers, and routers. See also RTP (Routing Table Protocol)

SS7

Signaling System 7 Standard CCS system used with BISDN and ISDN. Developed by Bellcore. See also CCS

SSAP

source service access point SAP of the network node designated in the Source field of a packet. Compare to DSAP See also SAP (service access point)

SSCP

system services control points Focal points within an SNA network for managing network configuration, coordinating network operator and problem determination requests, and providing directory services and other session services for network end users.

SSCOP

Service Specific Connection Oriented Protocol Data link protocol that guarantees delivery of ATM signaling packets.

SSCS

service specific convergence sublayer One of the two sublayers of any AAL. SSCS, which is service dependent, offers assured data transmission. The SSCS can be null as well, in classical IP over ATM or LAN emulation implementations. See also AAL, ATM layer, CPCS, CS, and SAR

SSE

silicon switching engine Routing and switching mechanism that compares the data link or network layer header of an incoming packet to a silicon-switching cache, determines the appropriate action (routing or bridging), and forwards the packet to the proper interface. The SSE is directly encoded in the hardware of the SSP (Silicon Switch Processor) of a Cisco 7000 series router. It can therefore perform switching independently of the system processor, making the execution of routing decisions much quicker than if they were encoded in software. See also silicon switching and SSP. Cisco Systems Terms and Acronyms

SSL

Secure Socket Layer Encryption technology for the Web used to provide secure transactions such as the transmission of credit card numbers for e-commerce.

SSN

Subsystem number

SSP

1. Switch-to-Switch Protocol. Protocol specified in the DLSw standard that routers use to establish DLSw connections, locate resources, forward data, and handle flow control and error recovery. See also DLSw. 2. Silicon Switch Processor High-performance silicon switch for Cisco 7000 series routers that provides distributed processing and control for interface processors. The SSP leverages the high-speed switching and routing capabilities of the SSE to dramatically increase aggregate router performance, minimizing performance bottlenecks at the interface points between the router and a high-speed backbone. See also silicon switching and SSE. Cisco Systems Terms and Acronyms

STA

See spanning-tree algorithm

STD

Subseries of RFCs that specify Internet standards. The official list of Internet standards is in STD 1.

STM-1

Synchronous Transport Module level 1 One of a number of SDH formats that specifies the frame structure for the 155.52-Mbps lines used to carry ATM cells. See also SDH

STP

1. shielded twisted-pair. Two-pair wiring medium used in a variety of network implementations. STP cabling has a layer of shielded insulation to reduce EMI. Compare with UTP. See also twisted pair. 2. See Spanning-Tree Protocol.

STS-1

Synchronous Transport Signal level 1 Basic building block signal of SONET, operating at 51.84 Mbps. Faster SONET rates are defined as STS-n, where n is a multiple of 51.84 Mbps. See also SONET.

STS-3c

Synchronous Transport Signal level 3, concatenated SONET format that specifies the frame structure for the 155.52-Mbps lines used to carry ATM cells. See also SONET

STUN

serial tunnel Router feature allowing two SDLC- or HDLC-compliant devices to connect to one another through an arbitrary multiprotocol topology (using Cisco routers) rather than through a direct serial link. Cisco Systems Terms and Acronyms

SU

1. signaling unit. Another name for the TransPath product. 2. service unit or signaling unit.

SURAnet

Southeastern Universities Research Association Network. Network connecting universities and other organizations in the Southeastern United States. SURAnet, originally funded by the NSF and a part of the NSFNET, is now part of BBN Planet. See also BBN Planet, NSF, and NSFNET.

SVC

switched virtual circuit Virtual circuit that is dynamically established on demand and is torn down when transmission is complete. SVCs are used in situations where data transmission is sporadic. Called a switched virtual connection in ATM terminology. Compare with PVC.

T1

Digital WAN carrier facility. T1 transmits DS-1-formatted data at 1.544 Mbps through the telephone-switching network, using AMI or B8ZS coding. Compare with E1. See also AMI, B8ZS, and DS-1.

T.120

ITU standard that describes data conferencing. H.323 provides for the ability to establish T.120 data sessions inside of an existing H.323 session.

T3

Digital WAN carrier facility. T3 transmits DS-3-formatted data at 44.736 Mbps through the telephone switching network. Compare with E3 See also DS-3

TABS

Telemetry Asynchronous Block Serial AT&T polled point-to-point or multipoint communication protocol that supports moderate data transfer rates over intra-office wire pairs.

TAC

1. Terminal Access Controller. Internet host that accepts terminal connections from dial-up lines. 2. Cisco Technical Assistance Center There are 4 TACs worldwide. Cisco Systems Terms and Acronyms

TACACS

Terminal Access Controller Access Control System. Authentication protocol, developed by the DDN community, that provides remote access authentication and related services, such as event logging. User passwords are administered in a central database rather than in individual routers, providing an easily scalable network security solution. See also TACACS+

TACACS+

Terminal Access Controller Access Control System Plus Proprietary Cisco enhancement to Terminal Access Controller Access Control System (TACACS). Provides additional support for authentication, authorization, and accounting See also TACACS in main glossary. Cisco Systems Terms and Acronyms

TARP

TID Address Resolution Protocol In OSS, a protocol that resolves a TL-1 TID to a CLNP address (NSAP).

TB

Terabyte A+ Certification Training Kit

TC

transmission convergence Sublayer of the ATMphysical layer that transforms the flow of cells into a steady flow of bits for transmission over the physical medium. When transmitting, the TC sublayer maps the cells into the frame format, generates the HEC, and sends idle cells when there is nothing to send. When receiving, the TC sublayer delineates individual cells in the received bit stream and uses HEC to detect and correct errors. See also HEC and PHY

TCAP

transaction capabilities application part

TCC

terminating call control

TCL

tool command line

TCP

Transmission Control Protocol Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack. See also TCP/IP

TCP/IP

Transmission Control Protocol/Internet Protocol Common name for the suite of protocols developed by the U.S. DoD in the 1970s to support the construction of worldwide internetworks. TCP and IP are the two best-known protocols in the suite. See also IP and TCAP

TCU

trunk coupling unit In Token Ring networks, a physical device that enables a station to connect to the trunk cable.

TDM

time-division multiplexing Technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots. Bandwidth is allocated to each channel regardless of whether the station has data to transmit. Compare with ATDM, FDM, and statistical multiplexing

TDR

time domain reflectometer Device capable of sending signals through a network medium to check cable continuity and other attributes. TDRs are used to find physical layer network problems.

TEI

terminal endpoint identifier Field in the LAPD address that identifies a device on an ISDN interface. See also TE

TE

terminal equipment Any ISDN-compatible device that can be attached to the network, such as a telephone, fax, or computer.

telco

Abbreviation for telephone company

telex

Teletypewriter service allowing subscribers to send messages over the PSTN.

Telnet

Standard terminal emulation protocol in the TCP/IP protocol stack. Telnet is used for remote terminal connection, enabling users to log in to remote systems and use resources as if they were connected to a local system. Telnet is defined in RFC 854.

Tempest

U.S. military standard. Electronic products adhering to the Tempest specification are designed to withstand EMP. See also EMP

TERENA

Trans-European Research and Education Networking Association. Organization that promotes information and telecommunications technologies development in Europe. Formed by the merger of EARN and RARE. See also EARN and RARE

TEST

Texas Higher Education Network See THEnet

TFTP

Trivial File Transfer Protocol Simplified version of FTP that allows files to be transferred from one computer to another over a network.

TH

transmission header. SNA header that is appended to the SNA basic information unit (BIU). The TH uses one of a number of available SNA header formats. See also FID0, FID1, FID2, FID3, and FID4.

THEnet

Texas Higher Education Network Regional network comprising over 60 academic and research institutions in the Texas (United States) area.

TIA

Telecommunications Industry Association. Organization that develops standards relating to telecommunications technologies. Together, the TIA and the EIA have formalized standards, such as EIA/TIA-232, for the electrical characteristics of data transmission. See also EIA

TIC

Token Ring interface coupler Controller through which an FEP connects to a Token Ring.

TID

Terminal Identifier

TIOS

Transpath Input Output Subsystem

TIRKS

Trunk Information Record Keeping System Bellcore OSS that provides record keeping for interoffice trunk facilities. See also OSS

TL-1

Transaction Language One Bellcore term for intelligent network elements.

TLAP

TokenTalk Link Access Protocol Link-access protocol used in a TokenTalk network. TLAP is built on top of the standard Token Ring data-link layer.

TM

traffic management

TMN

Telecommunication Management Network ITU-T generic model for transporting and processing OAM&P information for a telecommunications network. See also OAM&P

TN3270

Terminal emulation software that allows a terminal to appear to an IBM host as a 3278 Model 2 terminal.

TNotify

Time Notify Specifies how often SMT initiates neighbor notification broadcasts. See also SMT

TOP

Technical Office Protocol OSI-based architecture developed for office communications.

ToS

type of service See CoS

TP0

Transport Protocol Class 0 OSI connectionless transport protocol for use over reliable subnetworks. Defined by ISO 8073.

TP4

Transport Protocol Class 4 OSI connection-based transport protocol. Defined by ISO 8073.

TPD

Mechanism used by some ATM switches that allows the remaining cells supporting an AAL5 frame to be discarded when one or more cells of that AAL5 frame are dropped. This avoids sending partial AAL5 frames through the ATM network when they will have to be retransmitted by the sender. Compare with EPD

TPPMD

twisted-pair physical medium dependent

traceroute

Program available on many systems that traces the path a packet takes to a destination. It is mostly used to debug routing problems between hosts. There is also a traceroute protocol defined in RFC 1393.

TRANSPAC

Major packet data network run by France Telecom. Transparent Asynchronous Transmitter/Receiver Interface 4-byte/5-byte

trap

Message sent by an SNMP agent to an NMS, console, or terminal to indicate the occurrence of a significant event, such as a specifically defined condition or a threshold that was reached. See also alarm and event.

TRIP

Token Ring Interface Processor High-speed interface processor on the Cisco 7000 series routers. The TRIP provides two or four Token Ring ports for interconnection with IEEE 802.5 and IBM Token Ring media with ports independently set to speeds of either 4 or 16 Mbps. Cisco Systems Terms and Acronyms

TRISL

Token Ring Inter-Switch Link

TSI

transmitting subscriber information Frame that can be sent by the caller with the caller’s telephone number that can be used to screen calls.

TSP

tag-switched path

TSR

Terminate-and-stay-resident program A+ Certification Training Kit

TTL

Time To Live Field in an IP header that indicates how long a packet is considered valid.

TUD

trunk up-down Protocol used in ATM networks that monitors trunks and detects when one goes down or comes up. ATMswitches send regular test messages from each trunk port to test trunk line quality. If a trunk misses a given number of these messages, TUD declares the trunk down. When a trunk comes back up, TUD recognizes that the trunk is up, declares the trunk up, and returns it to service. See also trunk.

TULIP

TCP and UDP over Lightweight IP Proposed protocol for running TCP and UDP applications over ATM.

TUNIP

TCP and UDP over Nonexistent IP Proposed protocol for running TCP and UPD applications over ATM.

TUV

German test agency that certifies products to European safety standards.

TWS

two-way simultaneous Mode that allows a router configured as a primary SDLC station to achieve better utilization of a full-duplex serial line. When TWS is enabled in a multidrop environment, the router can poll a secondary station and receive data from that station while it sends data to or receives data from a different secondary station on the same serial line.

TYMNET

See XStream

UA

unnumbered acknowledgement

UART

Universal Asynchronous Receiver/Transmitter Integrated circuit, attached to the parallel bus of a computer, used for serial communications. The UART translates between serial and parallel signals, provides transmission clocking, and buffers data sent to or from the computer.

UBR

unspecified bit rate QoS class defined by the ATM Forum for ATM networks. UBR allows any amount of data up to a specified maximum to be sent across the network, but there are no guarantees in terms of cell loss rate and delay. Compare with ABR, CBR, and VBR.

UBR+

unspecified bit rate plus UBR service complemented by ATM switches that use intelligent packet discard mechanisms such as EPD or TPD. See also EPD and TPD

UCM

universal call model

UDLP

UniDirectional Link Protocol Protocol used by inexpensive, receive-only antennas to receive data via satellite.

UDP

User Datagram Protocol Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.

U-frame

Unnumbered frame One of three SDLC frame formats. See also I-frame and S-frame.

UI

unnumbered information.

UIO

Universal I/O serial port (Cisco router).

UKERNA

UK Education and Research Networking Association

UL

Underwriters Laboratories Independent agency within the United States that tests product safety.

ULP

upper-layer protocol Protocol that operates at a higher layer in the OSI reference model, relative to other layers. ULP is sometimes used to refer to the next-highest protocol (relative to a particular protocol) in a protocol stack.

UMB

Upper memory block A+ Certification Training Kit

UNI

User-Network Interface ATM Forum specification that defines an interoperability standard for the interface between ATM-based products (a router or an ATM switch) located in a private network and the ATM switches located within the public carrier networks. Also used to describe similar connections in Frame Relay networks. See also NNI, Q.920/Q.921, and SNI (Subscriber Network Interface).

UNIX

Operating system developed in 1969 at Bell Laboratories. UNIX has gone through several iterations since its inception. These include UNIX 4.3 BSD (Berkeley Standard Distribution), developed at the University of California at Berkeley, and UNIX System V, Release 4.0, developed by AT&T.

UPS

Uninterruptible power supply A+ Certification Training Kit

URL

Universal Resource Locator Standardized addressing scheme for accessing hypertext documents and other services using a browser. See also browser.

USB

Universal serial bus A+ Certification Training Kit

USENET

Initiated in 1979, one of the oldest and largest cooperative networks, with over 10,000 hosts and a quarter of a million users. Its primary service is a distributed conferencing

UTC

Coordinated Universal Time Time zone at zero degrees longitude. Formerly called Greenwich Mean Time (GMT) and Zulu time.

UTP

unshielded twisted-pair Four-pair wire medium used in a variety of networks. UTP does not require the fixed spacing between connections that is necessary with coaxial-type connections. There are five types of UTP cabling commonly used: Category 1 cabling, Category 2 cabling, Category 3 cabling, Category 4 cabling, and Category 5 cabling. Compare with STP. See also EIA/TIA-586 and twisted pair.

UTS

P1024C data-link layer protocol.

UUCP

UNIX-to-UNIX Copy Program Protocol stack used for point-to-point communication between UNIX systems.

uuencode

UNIX-to-UNIX encoding Method of converting binary files to ASCII so that they can be sent over the Internet via e-mail. The name comes from its use by the UNIX operating system’s uuencode command. See also uudecode

uudecode

UNIX-to-UNIX decode Method of decoding ASCII files that were encoded using uuencode. See also uuencode

UVM

Universal Voice Module

V.24

ITU-T standard for a physical layer interface between DTE and DCE. V.24 is essentially the same as the EIA/TIA-232 standard. See also EIA/TIA-232

V.25bis

ITU-T specification describing procedures for call setup and tear down over the DTE-DCE interface in a PSDN.

V.32

ITU-T standard serial line protocol for bidirectional data transmissions at speeds of 4.8 or 9.6 Kbps. See also V.32bis

V.32bis

ITU-T standard that extends V.32 to speeds up to 14.4 Kbps. See also V.32

V.34

ITU-T standard that specifies a serial line protocol. V.34 offers improvements to the V.32 standard, including higher transmission rates (28.8 Kbps) and enhanced data compression. Compare with V.32

V.35

ITU-T standard describing a synchronous, physical layer protocol used for communications between a network access device and a packet network. V.35 is most commonly used in the United States and in Europe, and is recommended for speeds up to 48 Kbps.

V.42

ITU-T standard protocol for error correction using LAPM. See also LAPM

VAC

volts alternating current

VAD

voice activity detection When enabled on voice port or a dial peer, silence is not transmitted over the network, only audible speech. When VAD is enabled, the sound quality is slightly degraded, but the connection monopolizes much less bandwidth.

VBR

variable bit rate QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a real time (RT) class and non-real time (NRT) class. VBR (RT) is used for connections in which there is a fixed timing relationship between samples. VBR (NRT) is used for connections in which there is no fixed timing relationship between samples, but that still need a guaranteed QoS. Compare with ABR, CBR, and UBR.

VCC

virtual channel connection Logical circuit, made up of VCLs, that carries data between two end points in an ATM network. Sometimes called a virtual circuit connection. See also VCD, VCL, and VPI

VCD

virtual circuit descriptor

VCI

virtual channel identifier 16-bit field in the header of an ATM cell. The VCI, together with the VPI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next network VCL that a cell needs to transit on its way to its final destination. The function of the VCI is similar to that of the DLCI in Frame Relay. Compare with DLCI See also VCL and VPI

VCL

virtual channel link Connection between two ATM devices. A VCC is made up of one or more VCLs. See also VCC

VCN

virtual circuit number 12-bit field in an X.25 PLP header that identifies an X.25 virtual circuit. Allows DCE to determine how to route a packet through the X.25 network. See also LCI and LCN

VDC

volts direct current

VDSL

very-high-data-rate digital subscriber line One of four DSL technologies. VDSL delivers 13 to 52 Mbps downstream and 1.5 to 2.3 Mbps upstream over a single twisted copper pair. The operating range of VDSL is limited to 1,000 to 4,500 feet (304.8 to 1,372 meters). Compare with ADSL, HDSL, and SDSL

Veronica

Very Easy Rodent Oriented Netwide Index to Computer Archives Gopher utility that effectively searches Gopher servers based on a user’s list of keywords.

VESA

Video Electronics Standards Association A+ Certification Training Kit

VF

variance factor One of three link attributes exchanged using PTSPs to determine the available resources of an ATM network. VF is a relative measure of CRM normalized by the variance of the aggregate cell rate on the link.

VGA

Video Graphics Adapter A+ Certification Training Kit

VINES

Virtual Integrated Network Service NOS developed and marketed by Banyan Systems.

VIP

1. Versatile Interface Processor Interface card used in Cisco 7000 and Cisco 7500 series routers. The VIP provides multilayer switching and runs Cisco IOS. The most recent version of the VIP is VIP2. 2. virtual IP Function that enables the creation of logically separated switched IP workgroups across the switch ports of a Catalyst 5000 running Virtual Networking Services software. See also Virtual Networking Services. Cisco Systems Terms and Acronyms

VLAN

virtual LAN Group of devices on one or more LANs that are configured (using management software) so that they can communicate as if they were attached to the same wire, when in fact they are located on a number of different LAN segments. Because VLANs are based on logical instead of physical connections, they are extremely flexible.

VLB

VESA local bus A+ Certification Training Kit

VLI

virtual LAN internetwork Internetwork composed of VLANs. See also VLAN

VLSM

variable-length subnet mask Ability to specify a different subnet mask for the same network number on different subnets. VLSM can help optimize available address space.

VMAC

Virtual Media Access Control

VNS

See Virtual Networking Services Cisco Systems Terms and Acronyms

VoATM

Voice Over ATM Voice over ATM enables a router to carry voice traffic (for example, telephone calls and faxes) over an ATM network. When sending voice traffic over ATM, the voice traffic is encapsulated using a special AAL5 encapsulation for multiplexed voice.

VoFR

Voice Over Frame Relay Voice over Frame Relay enables a router to carry voice traffic (for example, telephone calls and faxes) over a Frame Relay network. When sending voice traffic over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network using FRF.12 encapsulation.

VoHDLC

Voice Over HDLC Voice over HDLC enables a router to carry live voice traffic (for example, telephone calls and faxes) back-to-back to a second router over a serial line.

VoIP

Voice over IP The ability to carry normal telephony-style voice over an IP-based internet with POTS-like functionality, reliability, and voice quality

VOM

Volt ohm meter A+ Certification Training Kit

VP

virtual path One of two types of ATM circuits identified by a VPI. A virtual path is a bundle of virtual channels, all of which are switched transparently across an ATM network based on a common VPI. See also VPI

VPC

virtual path connection Grouping of VCCs that share one or more contiguous VPL. See also VCC and VPL

VPDN

virtual private dial-up network See also VPN

VPI

virtual path identifier 8-bit field in the header of an ATM cell. The VPI, together with the VCI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next VCL that a cell needs to transit on its way to its final destination. The function of the VPI is similar to that of the DLCI in Frame Relay. Compare with DLCI. See also VCD and VCL

VPL

virtual path link Within a virtual path, a group of unidirectional VCLs with the same end points. Grouping VCLs into VPLs reduces the number of connections to be managed, thereby decreasing network control overhead and cost. A VPC is made up of one or more VPLs.

VPN

Virtual Private Network Enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another. A VPN uses “tunneling” to encrypt all information at the IP level.

VRML

Virtual Reality Modeling Language Specification for displaying 3-dimensional objects on the World Wide Web. Think of it as the 3-D equivalent of HTML.

VRR

Vertical refresh rate A+ Certification Training Kit

VSC

Cisco’s virtual switch controller. Cisco Systems Terms and Acronyms

VSI

Virtual Switch Interface

VS/VD

virtual source/virtual destination

VT-n

Virtual Tributary level n SONET format for mapping a lower-rate signal into a SONET payload. For example, VT-1.5 is used to transport a DS-1 signal. See also DS-1 and SONET.

VTAM

virtual telecommunications access method Set of programs that control communication between LUs. VTAM controls data transmission between channel-attached devices and performs routing functions. See also LU

VTP

Virtual Terminal Protocol ISO application for establishing a virtual terminal connection across a network

vty

virtual type terminal but commonly used as virtual terminal lines.

WAIS

Wide Area Information Server Distributed database protocol developed to search for information over a network. WAIS supports full-text databases, which allow an entire document to be searched for a match (as opposed to other technologies that only allow an index of key words to be searched).

WAN

wide-area network Data communications network that serves users across a broad geographic area and often uses transmission devices provided by common carriers. Frame Relay, SMDS, and X.25 are examples of WANs. Compare with LAN and MAN

WDM

wave division multiplexing

WDCS

Wideband Digital Crossconnect System SONET DCS capable of crossconnecting DS-1 and VT1.5 signals. See also DCS, DS-1, SONET, and VT-n.

WFQ

weighted fair queuing Congestion management algorithm that identifies conversations (in the form of traffic streams), separates packets that belong to each conversation, and ensures that capacity is shared fairly between these individual conversations. WFQ is an automatic way of stabilizing network behavior during congestion and results in increased performance and reduced retransmission.

WinSock

Windows Socket Interface Software interface that allows a wide variety of applications to use and share an Internet connection. WinSock is implemented as dynamic link library (DLL) with some supporting programs, such as a dialer program that initiates the connection.

WISCNET

TCP/IP network in Wisconsin (United States) connecting University of Wisconsin campuses and a number of private colleges. Links are 56 Kbps and T1.

WRAM

Window random access memory A+ Certification Training Kit

WWW

World Wide Web Large network of Internet servers providing hypertext and other services to terminals running client applications such as a browser.

X.121

ITU-T standard describing an addressing scheme used in X.25 networks. X.121 addresses are sometimes called IDNs.

X.21

ITU-T standard for serial communications over synchronous digital lines. The X.21 protocol is used primarily in Europe and Japan.

X.21bis

ITU-T standard that defines the physical layer protocol for communication between DCE and DTE in an X.25 network. Virtually equivalent to EIA/TIA-232. See also EIA/TIA-232 and X.25.

X.25

ITU-T standard that defines howconnections between DTE and DCE are maintained for remote terminal access and computer communications in PDNs. X.25 specifies LAPB, a data link layer protocol, and PLP, a network layer protocol. Frame Relay has to some degree superseded X.25. See also Frame Relay, LAPB, and PLP.

X.28

ITU-T recommendation that defines the terminal-to-PAD interface in X.25 networks. See also PAD and X.25

X.29

ITU-T recommendation that defines the form for control information in the terminal-to-PAD interface used in X.25 networks. See also PAD and X.25

X.3

ITU-T recommendation that defines various PAD parameters used in X.25 networks. See also PAD and X.25

X3T9.5

Number assigned to the ANSI Task Group of Accredited Standards Committee for their internal, working document describing FDDI.

X.400

ITU-T recommendation specifying a standard for e-mail transfer.

X.500

ITU-T recommendation specifying a standard for distributed maintenance of files and directories.

X.75

ITU-T specification that defines the signaling system between two PDNs. X.75 is essentially an NNI. See also NNI

XDMCP

X Display Manager Control Protocol Protocol used to communicate between X terminals and workstations running the UNIX operating system.

XDR

eXternal Data Representation Standard for machine-independent data structures developed by Sun Microsystems. Similar to BER.

xDSL

Group term used to refer to ADSL, HDSL, SDSL and VDSL. All are emerging digital technologies using the existing copper infrastructure provided by the telephone companies. xDSL is a high-speed alternative to ISDN.

XE

TransPath Execution Environment Layer of software providing shared services for all application software on the TransPath and isolating higher-level software from operating system dependencies.

XID

exchange identification. Request and response packets exchanged prior to a session between a router and a Token Ring host. If the parameters of the serial device contained in the XID packet do not match the configuration of the host, the session is dropped.

XML

eXtensible Markup Language Text markup language designed to enable the use of SGML on the World-Wide Web. XML allows you to define your own customized markup language.

XMS

Extended memory specification A+ Certification Training Kit

XNS

Xerox Network Systems Protocol suite originally designed by PARC. Many PC networking companies, such as 3Com, Banyan, Novell, and UB Networks used or currently use a variation of XNS as their primary transport protocol. See also X Window System.

XOT

X.25 over TCP

XStream

Major public PSN in the United States operated by MCI. Formerly called TYMNET.

XTagATM

extended tag ATM

ZIF

Zero insertion force A+ Certification Training Kit

ZIP

Zone Information Protocol AppleTalk session layer protocol that maps network numbers to zone names. ZIP is used by NBP to determine which networks contain nodes that belong to a zone. See also ZIP storm and zone.







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