Glossary

CCITT

International Consultative Committee for Telegraphy and Telephony.

CONS

Connection-Oriented Network Service.

DCE

Data Circuit-Terminating Equipment.

DDN

Defense Data Network.

DNIC

Data Network Identification Code.

DSAP

Destination Service Access Point.

DTE

Data Terminal Equipment. The user equipment (computer, terminal, etc.) connected to a network.

Ethernet

Ethernet, or IEEE 802.3, is a network based on an access method called CSMA/CD. Ethernet was originally developed by the Xerox Corporation in 1972. A specification was published in 1980 for other implementors to use.

Ethernet Address

A 48-bit station identifier. Each network node has a unique address. The high-order bytes are usually manufacturer-specific. Certain reserved addresses have special meaning.

getty

A process that handles incoming calls.

IEEE

Institute of Electrical and Electronic Engineers.

Internet Address

A 32-bit address used to identify nodes on the network that use the Internet Protocol.

ISO

International Organization for Standardization.

IXE

IP to X.25 Encapsulation.

LAN

A Local Area Network, where several hosts and devices are located near each other and connected physically by cables. Typically, these cables are Ethernet coaxial cables.

LAP

Link Access Procedure.

LAPB

Link Access Procedure - Balanced.

LCI

Logical Channel Identifier.

LLC

Logical Link Control.

LLC-2

Logical Link Control - Class II.

LSAP

Link Service Access Point.

NLI

Network Layer Interface.

NSAP

Network Service Access Point.

OSI

Open Systems Interconnection.

Packet

Units of information that contain a header with addresses and handling information and a message. Longer messages can be split up into several different packets and sent separately.

PAD

Packet Assembler/Disassembler. A means of interfacing a character terminal to an X.25-based network.

PDU

Protocol Data Unit.

PVC

Permanent Virtual Circuit.

RFC

A “Request for Comment” discussion document, produced by interested parties, which may be adopted as a standard by the Internet Activities Board.

RPOA

Recognized Private Operating Agency.

SNPA

Subnetwork Point of Attachment.

SSAP

Source Service Access Point.

STREAMS

A set of system calls, kernel resources, and utility routines that create, use, and dismantle a stream.

Subnetwork

In this document, this term refers to a single physical DTE/DCE link or a single physical Ethernet link.

TOA/NPI

Type Of Address / Numbering Plan Identification. An address format that provides increased addressing capacity suitable for communication with ISDNs.

VC

Virtual Call.

WAN

Wide Area Network. Computers with long distances between them connected by, for example, telephone lines.

X.25

The CCITT recommendations covering network access protocols for ISO layers 1, 2, and 3 made in 1980, 1984, and 1988.

X.3, X.28, X.29

The CCITT recommendations covering PAD operation made in 1980, 1984, and 1988.