Cabletron Systems WPIM-DI, Сетевое руководство

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Appendix D: WAN Terms and Acronyms
D-2 WPIM-DI Local Management Guide
DCE Data Communications Equipment, a device such as a
modem that connects the communications circuit with
the end device (see DTE).
Data (D)
Channel A 16 Kbps channel used with BRI and PRI services for
signaling and control.
D4 D4 Framing, a popular framing format in T-1. Uses 12
T-1 Frames to identify both the channel and the signaling
bit.
DI
Drop and Insert, a function provided on the Cabletron
Systems WPIM-DI which allows the user to map
timeslots that are not being used to another WAN device.
DLCI
Data Link Connection Identifier, a unique virtual circuit
identifier used in Frame Relay. Identifies a given frame as
being from a particular logical link. The DLCI has only
local significance.
DSU Digital Service Unit, converts RS-232 or other terminal
interfaces to DSX-1 (T-1) interface.
DS-0
Digital Signal, level 0, a standard 64,000 bit/second
channel. Synonymous with “Timeslot.”
DTE
Data Terminal Equipment, equipment that originates and
terminates data transmission such as a computer or
printer (see DCE).
E-1
European digital signal level 1. Similar to T-1 but
provides 32 channels (2.048 Mbps) instead of 24
channels (1.544 Mbps).
ESF
Extended Super Frame. A new T-1 framing standard (see
D4 framing) that uses 24 T-1 frames, thus allowing
individual identification of the channel and signaling bits.
Fractional T-1
Use of a portion (less than the full 24 channels) of a T-1
line.
Frame Relay A network protocol that allows for many point-to-point
virtual connections over a single access channel.