network administrator segments a network into sub-
networks in order to provide a hierarchical, multilevel
routing structure, and at the same time protect the
subnetwork from the addressing complexity of net-
works 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 col-
lection of ESs and ISs controlled by only one adminis-
trative domain, using a solitary network connection
protocol.
as soon as transmission is over and the circuit is no
longer needed. In ATM terminology, it is referred to as
a switched virtual connection. See also: PVC.
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 elec-
tronic/mechanical device allowing connections to be
established as needed and terminated if no longer nec-
essary.
ples are process swithcing, fast switching, optimum,
CEF, dCEF, and distributed switching.
identical frequencies and contain individual characters
encapsulated in control bits (called start/stop bits) that
designate the beginning and ending of each character.
See also: asynchronous transmission and isochronous
transmission.
network.
overhead, providing 1.544Mbps of usable bandwidth.
length labels that control the manner in which data is
to be sent, tag switching is a high-performance tech-
nology used for forwarding packets. It incorporates
Data-Link layer (Layer 2) switching and Network
layer (Layer 3) routing and supplies scalable, high-
speed switching in the network core.
(DE) traffic. Tagged traffic can be eliminated in order
to ensure trouble-free delivery of higher priority traf-
fic, if the network is congested. See also: CLP.
of the OSI reference model. Provides reliable delivery
of data.
TCP and IP are the most widely known protocols in
that suite. See also: IP and TCP.
signed time slots, to data from several channels. Band-
width is allotted to each channel regardless of a
station's ability to send data. See also: ATDM, FDM,
and multiplexing.
lems in a cable. They can detect where an open circuit,
short circuit, crimped wire, or other abnormality is
located in a cable.
a telephone or computer. TE1s are devices that are
ISDN-ready and understand ISDN signaling tech-
niques. TE2s are devices that are not ISDN-ready and
do not understand ISDN signaling techniques. A ter-
minal adapter must be used with a TE2.