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Glossary

Digital WAN that can provide bandwidth of 44.763Mbps.

TACACS+

Terminal Access Controller Access Control System: An

enhanced version of TACACS, this protocol is similar to RADIUS. See
also: RADIUS.

tag switching

Based on the concept of label swapping, where packets or

cells are designated to defined-length labels that control the manner in which
data is to be sent, tag switching is a high-performance technology 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.

tagged traffic

ATM cells with their cell loss priority (CLP) bit set to 1.

Also referred to as Discard Eligible (DE) traffic. Tagged traffic can be elim-
inated in order to ensure trouble-free delivery of higher priority traffic, if the
network is congested. See also: CLP.

TCP

Transmission Control Protocol: A connection-oriented protocol that

is defined at the transport layer of the OSI reference model. Provides reliable
delivery of data.

TCP/IP

Transmission Control Protocol/Internet Protocol. The suite of pro-

tocols underlying the Internet. TCP and IP are the most widely known
protocols in that suite. See also: IP and TCP.

TDM

Time Division Multiplexing: A technique for assigning bandwidth on

a single wire, based on preassigned time slots, to data from several channels.
Bandwidth is allotted to each channel regardless of a station's ability to send
data. See also: ATDM, FDM, and multiplexing.

terminal equipment: Any peripheral device that is ISDN-compatible

and attached to a network, such as a telephone or computer. TE1s are
devices that are ISDN-ready and understand ISDN signaling techniques.
TE2s are devices that are not ISDN-ready and do not understand ISDN sig-
naling techniques. A terminal adapter must be used with a TE2.

TE1

A device with a four-wire, twisted-pair digital interface is referred to

as terminal equipment type 1. Most modern ISDN devices are of this type.

TE2

Devices known as terminal equipment type 2 do not understand

ISDN signaling techniques, and a terminal adapter must be used to con-
vert the signaling.

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