[asterisk-bugs] [Asterisk 0017973]: Asterisk messes up progress indication on q.931 ALERTING message

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17973 
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Reported By:                jpokorny
Assigned To:                
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Project:                    Asterisk
Issue ID:                   17973
Category:                   Channels/chan_dahdi
Reproducibility:            have not tried
Severity:                   major
Priority:                   normal
Status:                     new
Asterisk Version:           Older 1.6.2 - please test a newer version 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-09-09 05:10 CDT
Last Modified:              2010-09-13 10:28 CDT
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Summary:                    Asterisk messes up progress indication on q.931
ALERTING message
Description: 
I am using asterisk with libpri 1.4.11, dahdi 2.3.0.1 and two ISDN PRI E1
interfaces. Asterisk seems to have trouble with some outgoing calls
signalization. Scenario:

1) inbound call to asterisk from user (SETUP and CALL PROCEEDING with
user)
2) outbound call is dialed (SETUP and CALL PROCEEDING to PBX)
3) ALERTING message comes on the outbound channel, with no progress
indication
4) ALERTING is sent to inbound channel, WITH progress indication 8 (Inband
information or appropriate pattern now available)
5) but no sound is generated on the inbound channel
6) user hears nothing, few seconds later, he is connected

This scenario is catched up in the attached log. I recorded channels using
dahdi_monitor to confirm the sound is not generated. Asterisk should either
send ALERTING with no progress or generate the sound.

Unfortunately PBX does usually follow the ALERTING message with PROGRESS
and inband audio, which works ok, so I can't reproduce it easily. I am not
sure if this is chan_dahdi or libpri issue.

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 (0126881) lmadsen (administrator) - 2010-09-13 10:28
 https://issues.asterisk.org/view.php?id=17973#c126881 
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Per rmudgett:  "It is a chan_dahdi issue that is very very old (Since
libpri support was added.).  It may involve the asterisk core since the
ALERTING indicates that there is no audio.  Asterisk needs to either
generate ringback tones or pass on that there is no audio available."

This is a note for future development. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-09-13 10:28 lmadsen        Note Added: 0126881                          
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