ADTRAN DSU IV ESP, User Manual

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Appendix H. Glossary
61204011L1-1 DSU IV ESP User Manual H-5
forward explicit congestion notification (FECN)
A bit set by a frame relay network to notify an interface device (DTE) that con-
gestion avoidance procedures should be initiated by the receiving device. See
also BECN.
frame check sequence (FCS)
The standard 16-bit cyclic redundancy check used for HDLC and frame relay
frames. The FCS detects bit errors occurring in the bits of the frame between the
opening flag and the FCS, and is only effective in detecting errors in frames no
larger than 4096 octets. See also cyclic redundancy check (CRC).
frame-relay-capable interface device
A communications device that performs encapsulation. Frame-relay-capable
routers and bridges are examples of interface devices used to interface the cus-
tomer's equipment to frame relay network. See also interface device and encap-
sulation.
frame relay frame
A variable-length unit of data, in frame-relay format that is transmitted through
a frame relay network as pure data. Contrast with packet.
frame relay network
A telecommunications network based on frame relay technology. Data is multi-
plexed. Contrast with packet switching network.
gateway
A device which enables information to be exchanged between two dissimilar
systems or networks.
high level data link control (HDLC)
A generic link-level communications protocol developed by the International
Organization for Standardization (ISO). HDLC manages synchronous code-
transparent, serial information transfer over a link connection. See also synchro-
nous data link control (SDLC).
host computer
The primary or controlling computer in a multiple computer operation.
in-band
Signaling (dialing, diagnostics, management, configuration, etc.) over the same
channel used for data.