Glossary

(ANSI) Standard T1.618 and the International Telegraph and Telephone Consultative Committee (CCITT) Standard Q.922, indicates the functions associated with certain DLCI values:

DLCI

Function

Values

 

 

 

0

In-channel signalling

 

 

1-15

Reserved

 

 

16-991

Assigned using frame-relay connection procedures

 

 

992-1007

Layer 2 management of frame-relay bearer service

 

 

1008-1022

Reserved

 

 

1023

In-channel layer management

 

 

DCD (Data Carrier Detect) ‹ See CD (Carrier Detect).

DCE (Data Communications Equipment, Data Circuit-terminating Equipment) ‹ Equipment that provides the functions required to establish, maintain, and terminate a connection (including signal con- version) for communications between the data terminal equipment and the telephone line or data circuit. Also, interface signals typically presented by this equipment.

D channel ‹ Standard channel on an ISDN PRI or BRI line. At 16 Kbps, a D channel carries all signalling information and can carry low- speed packet data such as X.25 packet switching.

DE ‹ See discard eligibility.

Demarc (demarcation point) ‹ The point on a customer's premises where the line from the telephone company meets the customer's wiring at the customer's premises.

DFT ‹ See Distributed Function Terminal.

Directory Number ‹ Your seven-digit telephone number (without the area code), as found in the telephone directory. Each BRI connection can have up to two Directory Numbers, one for each B channel.

Discard eligibility (DE) ‹ A bit indicating that a frame may be discarded in preference to other frames if congestion occurs to maintain the committed information rate. See also excess burst size (Be) and CIR.

5536 PRI RAS Communications Controller Users Guide

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