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Glossary
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 a 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 in both
directions simultaneously.
sliding window
The method of flow control used by TCP, as well as sev-
eral Data Link layer protocols. This method places a buffer between the
receiving application and the network data flow. The "window" available
for accepting data is the size of the buffer minus the amount of data already
there. This window increases in size as the application reads data from it and
decreases as new data is sent. The receiver sends the transmitter announce-
ments of the current window size, and it may stop accepting data until the
window increases above a certain threshold.
SLIP
Serial Line Internet Protocol: An industry standard serial encapsula-
tion for point-to-point connections that supports only a single routed pro-
tocol, TCP/IP. SLIP is the predecessor to PPP. See also: PPP.
SMDS
Switched Multimegabit Data Service: A packet-switched,
datagram-based WAN networking technology offered by telephone compa-
nies that provides high speed.
SMTP
Simple Mail Transfer Protocol: A protocol used on the Internet to
provide electronic mail services.
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