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Glossary
subarea node
An SNA communications host or controller that handles
entire network addresses.
subchannel
A frequency-based subdivision that creates a separate broad-
band communications channel.
subinterface
One of many virtual interfaces available on a single physical
interface.
subnet
See: subnetwork.
subnet address
The portion of an IP address that is specifically identified
by the subnet mask as the subnetwork. See also: IP address, subnetwork, and
subnet mask.
subnet mask
Also simply known as mask, a 32-bit address mask used in
IP to identify the bits of an IP address that are used for the subnet address.
Using a mask, the router does not need to examine all 32 bits, only those
selected by the mask. See also: address mask and IP address.
subnetwork
1) Any network that is part of a larger IP network and is iden-
tified by a subnet address. A network administrator segments a network into
subnetworks in order to provide a hierarchical, multilevel routing structure,
and at the same time protect the subnetwork from the addressing complexity
of networks that are attached. Also known as a subnet. See also: IP address,
subnet mask, and subnet address. 2) In OSI networks, the term specifically
refers to a collection of ESs and ISs controlled by only one administrative
domain, using a solitary network connection protocol.
SVC
switched virtual circuit: A dynamically established virtual circuit, cre-
ated on demand and dissolved as soon as transmission is over and the circuit
is no longer needed. In ATM terminology, it is referred to as a switched vir-
tual connection. See also: PVC.
switch
1) In networking, a device responsible for multiple functions such
as filtering, flooding, and sending frames. It works using the destination
address of individual frames. Switches operate at the Data Link layer of the
OSI model. 2) Broadly, any electronic/mechanical device allowing connec-
tions to be established as needed and terminated if no longer necessary.
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