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Glossary

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security policy

Document that defines the business requirements and pro-

cesses that are to be used to protect corporate data. A security policy might
be as generic as "no file transfers allowed" to very specific, such as "FTP puts
allowed only to server X."

security server

A centralized device that authenticates access requests,

typically via a protocol such as TACACS+ or RADIUS. See also: TACACS+,
RADIUS.

seed router

In an AppleTalk network, the router that is equipped with the

network number or cable range in its port descriptor. The seed router spec-
ifies the network number or cable range for other routers in that network
section and answers to configuration requests from nonseed routers on its
connected AppleTalk network, permitting those routers to affirm or modify
their configurations accordingly. Every AppleTalk network needs at least
one seed router physically connected to each network segment.

server

Hardware and software that provide network services to clients.

Session layer

Layer 5 of the OSI reference model, responsible for cre-

ating, managing, and terminating sessions between applications and over-
seeing data exchange between Presentation layer entities. See also:
Application layer, Data Link layer, Network layer, Physical layer, Presenta-
tion layer, and Transport layer.

set-based

Set-based routers and switches use the set command to con-

figure devices. Cisco is moving away from set-based commands and is using
the Command-Line Interface (CLI) on all new devices.

setup mode

Mode that a router will enter if no configuration is found in

nonvolatile RAM when the router boots. Allows the administrator to con-
figure a router step-by-step. Not as robust or flexible as the Command-Line
Interface.

super frame: A super frame (also called a D4 frame) consists of 12

frames with 192 bits each, and the 193rd bit providing other functions
including error checking. SF is frequently used on T1 circuits. A newer ver-
sion of the technology is Extended Super Frame (ESF), which uses 24 frames.
See also: ESF.

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