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Glossary
server
Hardware and software that provide network services to clients.
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.
session layer
Layer 5 of the OSI reference model, responsible for creating,
managing, and terminating sessions between applications and overseeing
data exchange between presentation layer entities. See also: application
layer, data link layer, network layer, physical layer, presentation layer,
and transport layer.
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.
SF
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.
shared trees
A method of multicast data forwarding. Shared trees use an
architecture in which multiple sources share a common rendezvous point.
signaling packet
An informational packet created by an ATM-connected
mechanism that wants to establish connection with another such mecha-
nism. The packet contains the QoS parameters needed for connection and
the ATM NSAP address of the endpoint. The endpoint responds with a mes-
sage of acceptance if it is able to support the desired QoS, and the connection
is established. See also: QoS.
silicon switching
A type of high-speed switching used in Cisco 7000
series routers, based on the use of a separate processor (the Silicon Switch
Processor, or SSP). See also: SSE.
simplex
The mode at which data or a digital signal is transmitted. Simplex
is a way of transmitting in only one direction. Half duplex transmits in two
directions but only one direction at a time. Full duplex transmits both direc-
tions simultaneously.
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