[asterisk-bugs] [LibPRI 0012153]: librpi: Data link layer does not re-establish connection as described in section 5.8.9 of Q.931

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
====================================================================== 
http://bugs.digium.com/view.php?id=12153 
====================================================================== 
Reported By:                alerios
Assigned To:                mattf
====================================================================== 
Project:                    LibPRI
Issue ID:                   12153
Category:                   General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     assigned
Asterisk Version:           1.4.18 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
====================================================================== 
Date Submitted:             03-05-2008 15:21 CST
Last Modified:              03-05-2008 15:57 CST
====================================================================== 
Summary:                    librpi: Data link layer does not re-establish
connection as described in section 5.8.9 of Q.931
Description: 
I'm having incoming call drops in different systems, all with the same
pattern:   

The call is established normally, with STETUP, CALL_PROCEDING, CONNECT,
and CONNECT_ACK, but then after a random while we get a DISCONNECT (cause
27) from the Telco, followed by our RELEASE and RELEASE_COMPLETE.

According to section 5.8.9 of ITU-T Q.931 (05/98), the DISCONNECT message
with cause 27 (destination out of order) is sent by the Telco wen its
internal T309 timer expires after trying to re-establish layer 2
connection.  Looking at the Q921 supervisory messages, it seems that no
frame errors are detected by libpri, or at least they are not shown.

This may be a telco side-issue related to their t309 timer, but I still
believe asterisk+libpri have something to do with it because when using an
ISDN tester or a legacy PBX the calls don't get dropped.
====================================================================== 

---------------------------------------------------------------------- 
 alerios - 03-05-08 15:57  
---------------------------------------------------------------------- 
mattf: I've just attached the .CSV log of an ISDN tester intercepting the
PRI line.

At the beggining of the file you will find a call processed by the tester
as end point, terminating with a normal DISCONNECT cause 16 message after
some minutes of talking.
Then there are a couple of alarms, when disconnecting the pri line and
connecting it to the Asterisk system.  Then you will find the call with
asterisk as end point, with the abnormal DISCONNECT cause 27 message
droping the call after less than 2 minutes.

The calling A number was the same for both calls, so the problem was
reproducible all the time. 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
03-05-08 15:57  alerios        Note Added: 0083491                          
======================================================================