CAN/CSA-T542-90 (R2000)

Scope
 
 This standard contains the complete text of ccm Recommendation Q.920,
 ISDN User-Network Interface Data-Link Layer - General Aspects, and eeIIT
 Recommendation Q.921 , ISDN User-Network Interface - Data-Link Layer
 Specification, as they will appear in the upcoming 1989 eem Blue Book.!
 This standard specifies the Link Access Procedure on the D-channel,
 LAPD. The pwpose ofLAPD is to convey information between layer-3
 entities across the ISDN user-network interface using the D-channel.
 LAPD is a protocol operating at the data-link layer of the 051
 architecture. This standard specifies the use of LAPD on a duplex, bit-
 transparent D-channel on an ISDN interface. The frame structure,
 elements of procedure, format of fields, and procedures for the proper
 operation of LAPD are specified.