[asterisk-bugs] [Asterisk 0015784]: Simultaneous calls from same Call-ID silently ignored by asterisk

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=15784 
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Reported By:                m0bius
Assigned To:                
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Project:                    Asterisk
Issue ID:                   15784
Category:                   Channels/chan_sip/General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           SVN 
JIRA:                       SWP-221 
Regression:                 Yes 
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:             2009-08-27 05:40 CDT
Last Modified:              2009-10-23 13:11 CDT
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Summary:                    Simultaneous calls from same Call-ID silently
ignored by asterisk
Description: 
Hello everyone,

We have a follow-me system which terminates calls to an Asterisk server
which holds registrations for our VoIP users. In our follow-me system we
give the capability to the users to perform simultaneous follow-me to the
Asterisk Server (thus ringing two different voip accounts).

However I've noticed that on asterisk 1.6.1.1 and 1.6.1.4 when two calls
are sent simultaneously to different dialled numbers with the same Call-ID,
the second call does not enter the context. In a trace I did, I've seen
that asterisk responds to the SIP INVITE with Trying; however, that calls
stays there until it times out from the remote peer. 

The same thing has been tested on Asterisk 1.6.0.7 and 1.6.0.13 and it
works properly. I will attaching two traces (one from asterisk 1.6.0.7 and
one from asterisk 1.6.1.4)
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Relationships       ID      Summary
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related to          0016116 [patch] Fix/improve transaction/dialog-...
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 (0112675) klaus3000 (reporter) - 2009-10-23 13:11
 https://issues.asterisk.org/view.php?id=15784#c112675 
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That is what I already said: If a called is forked and multiple branches
are answered at the same time this is a race condition (which must be
handled by the caller, usually by sending BYE to all but one callees).


Back to the original problem - Asterisk does not respond to additional
branches of an INVITE transaction. There are 2 solutions: (A) Either reject
the additional branches or (B) accept (and enter dialplan execution) for
all branches.

(B) is probably difficult to implement (correct dialog identification) and
generates a race condition. As race conditions are a bad thing, Asterisk
should not generate them by purpose.

(A) should be much easier to implement, does not cause a race conditions
and does not cause problems with bad implemented UACs. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-10-23 13:11 klaus3000      Note Added: 0112675                          
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