[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 10:39 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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 (0112662) klaus3000 (reporter) - 2009-10-23 10:39
 https://issues.asterisk.org/view.php?id=15784#c112662 
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Just a note: If an incoming call is parallel forked on a previous hop (e.g.
SIP proxy) as in the following scenario

                                           +----------+
INV group -----> proxy ----INV user1------>| Asterisk |
                       \                   | Server   |
                        ---INV user2------>|          |
                                           +----------+

then on the first hand this is about identifiying transactions, not
dialog. So in this case, from transaction point of view, the From/To-tags
and callid are irrelevant - there are 2 different transactions identified
by different branch parameter in topmost Via header.

Of course the problem arise to more parameter analysis when actually
deciding what to do. Asterisk could answer (based on extensions.conf) both
branches, which can cause confusion to the caller, as then there are 2
dialogs established. The caller can be able to handle this situation and
has 2 calls open - I do not know any softwarwe which supports it, usually
the caller's client will send a BYE to one of the callees (or crash :-).

To allow creation of 2 dialogs/calls Asterisk needs proper dialog
identification. Callid,tags and remote contact will be identical, thus only
the local contact can be used to identifiy the 2 dialogs. 

Nevertheless establishing 2 dialogs usually will only confuse the caller
and IMO Asterisk should just reject the second branch, e.g. with 486. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-10-23 10:39 klaus3000      Note Added: 0112662                          
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