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Glossary

ASN.1

Abstract Syntax Notation One: An OSI language used to describe

types of data that is independent of computer structures and depicting
methods. Described by ISO International Standard 8824.

ASP

AppleTalk Session Protocol: A protocol employing ATP to establish,

maintain, and tear down sessions, as well as sequence requests. See also: ATP.

AST

Automatic Spanning Tree: A function that supplies one path for span-

ning explorer frames traveling from one node in the network to another, sup-
porting the automatic resolution of spanning trees in SRB networks. AST is
based on the IEEE 802.1 standard. See also: IEEE 802.1 and SRB.

asynchronous connection

Defines the start and stop of each octet. As a

result, each byte in asynchronous connections requires two bytes of over-
head. Synchronous connections use a synchronous clock to mark the start
and stop of each character.

asynchronous dial-up

Asynchronous dial-up is interchangeable with

analog dial-up. Both terms refer to traditional modem-based connections.

asynchronous transmission

Digital signals sent without precise timing,

usually with different frequencies and phase relationships. Asynchronous
transmissions generally enclose individual characters in control bits (called
start and stop bits) that show the beginning and end of each character. Con-
trast with: isochronous transmission and synchronous transmission.

ATCP

AppleTalk Control Program: The protocol for establishing and con-

figuring AppleTalk over PPP, defined in RFC 1378. See also: PPP.

ATDM

Asynchronous Time-Division Multiplexing: A technique for

sending information, it differs from normal TDM in that the time slots are
assigned when necessary rather than preassigned to certain transmitters.
Contrast with: FDM, statistical multiplexing, and TDM.

ATG

Address Translation Gateway: The mechanism within Cisco DECnet

routing software that enables routers to route multiple, independent DECnet
networks and to establish a user-designated address translation for chosen
nodes between networks.

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