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A phone's RELEASE_COMPLETE as a response to an initial broadcast SETUP blocks one B channel permantly when the call is cancelled. Scenario: A call to the ISDN Bus is acknowledged (ALERTING) by one phone/endpoint and rejected by another phone/endpoint with a RELEASE_COMPLETE. The call is then cancelled by the caller. If the whole procedure is repeated once again then any further call attempt is rejected (WARNING[5666]: app_dial.c:1546 dial_exec_full: Unable to create channel of type 'DAHDI' (cause 34 - Circuit/channel congestion)). It seems that receiving a RELEASE_COMPLETE in that state blocks one B channel permanently when the call is cancelled by the caller. Background: The ISDN phones (Siemens Gigaset 3035 or CX253) we use for testing additionally contain a DECT base station, which operates as a different endpoint on the ISDN Bus (TEI). If the DECT base station is not in use then there are no DECT phones registered to the base station. The DECT base station responds to an incoming call not directed toward it with (RELEASE_COMPLETE, cause: no user responding). * Made initiate_hangup_if_needed() also hangup the subcall if it is in the NULL state. * Simplified q931_set_subcall_winner(). JIRA ABE-2745 JIRA SWP-2954 git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@2207 2fbb986a-6c06-0410-b554-c9c1f0a7f128
libpri: An implementation of Primary Rate ISDN Written by Mark Spencer <markster@digium.com> What is libpri? =============== libpri is a C implementation of the Primary Rate ISDN specification. It was based on the Bellcore specification SR-NWT-002343 for National ISDN. As of May 12, 2001, it has been tested work with NI-2, Nortel DMS-100, and Lucent 5E Custom protocols on switches from Nortel and Lucent. What is the license for libpri? =============================== libpri is distributed under the terms of the GNU General Public License, which permit its use and linking with other GPL'd software only. The GNU GPL is included in the file LICENSE in this directory. As a special exception, libpri may also be linked to the OpenH323 library, so long as the entirity of the derivative work (as defined within the GPL) is licensed either under the MPL of the OpenH323 license or the GPL of libpri. If you wish to use libpri in an application for which the GPL is not appropriate (e.g. a proprietary embedded system), licenses for libpri under more flexible terms can be readily obtained through Digium, Inc. at reasonable cost. How do I report bugs or contribute? =================================== For now, contact the author directly. In the future if there is sufficient interest, we will setup a mailing list. Does anything use this library so far? ====================================== Yes, the Asterisk Open Source PBX does. http://www.asterisk.org Also, the Zapata library has hooks for it. http://www.zapatatelephony.org Special thanks ============== Special thanks to Jim Dixon <jim@lambdatel.com> for his help in testing and fixing the implementation.