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Glossary

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S reference point

ISDN reference point that works with a T reference

point to convert a 4-wire ISDN network to the 2-wire ISDN network needed
to communicate with the ISDN switches at the network provider.

sampling rate

The rate at which samples of a specific waveform ampli-

tude are collected within a specified period of time.

SAP

1) Service Access Point: A field specified by IEEE 802.2 that is part of

an address specification. 2) Service Advertising Protocol: The Novell Net-
Ware protocol that supplies a way to inform network clients of resources and
services availability on network, using routers and servers. See also: IPX.

SCR

Sustainable Cell Rate: An ATM Forum parameter used for traffic

management, it is the long-term average cell rate for VBR connections that
can be transmitted.

scripts

A script predefines commands that should be issued in sequence,

typically to complete a connection or accomplish a repetitive task.

SDLC

Synchronous Data Link Control: A protocol used in SNA data-link

layer communications. SDLC is a bit-oriented, full-duplex serial protocol
that is the basis for several similar protocols, including HDLC and LAPB. See
also: HDLC and LAPB.

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
specifies the network number or cable range for other routers in that net-
work 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.

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