ISDN Q.921 Link Access Procedure D Channel (LAPD)

The purpose of this project is to provide an ISDN Q.921 LAPD multiplexing driver that will link HDLC CDI streams and provide D-Channel signalling services to the ISDN Q.931 Call Control driver. The driver will perform automatic User-side TEI requests and allocation, and will pass Network-side TEI allocation requests up to the Layer 3 protocol.

The driver will provide SAPI 0 (LAPD) D-Channel signalling as well as SAPI 16 (LAPB) D-Channel packet.

This project was started January 2003.

This project is in the Testing stage.

This project depends on the HDLC project.

The design consists of a Data Link Provider Interface, dlpi(7), that provides LAPD data link services. HDLC streams providing the Communications Device Interface, cdi(7), can be linked under the module and configured using IO controls.

A detailed design has not yet been released.

A manual page for the lapd driver can be found here: lapd(4).

The driver will be tested to ITU-T Recommendation Q.921bis. Preliminary PICS/PIXIT have not yet been released.

Test results have not yet been released.

See ITU-T Recommendation Q.921.

Code can be found in the dl sub-directory of the strss7 release code.

This driver will be relased in the next major release (0.8.4) of the strss7 package.