[asterisk-bugs] [Asterisk 0013569]: Asterisk sending the wrong codec on re-invite.

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=13569 
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Reported By:                bkw918
Assigned To:                mnicholson
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Project:                    Asterisk
Issue ID:                   13569
Category:                   Channels/chan_sip/CodecHandling
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.6.0-rc6 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): 1.6.1 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2008-09-26 17:48 CDT
Last Modified:              2009-03-09 09:54 CDT
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Summary:                    Asterisk sending the wrong codec on re-invite.
Description: 
FreeSWITCH sends invite out to tf.voipmich.com with PCMU, PCMA, GSM.  The
call is answered and setup using GSM since its listed first in the Answer
we receive from Asterisk.  A re-invite promptly follows offering
GSM,PCMU,PCMA to which we 200 OK with ONLY GSM in the SDP in our 200 OK.  

Promptly there after Asterisk starts sending PCMU packets.  The re-invite
is considered a new Session Offer Answer and Asterisk ignores the Answer
and sends a media format not in the new Answer.  

Asterisk PBX SVN-branch-1.6.0-r140976-/trunk is what I can see in the SDP
from John's equipment.  He has disabled re-invites pending a fix for this.

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 (0101381) mnicholson (administrator) - 2009-03-09 09:54
 http://bugs.digium.com/view.php?id=13569#c101381 
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I understand what the RFC says.  I don't think you understand what is
happening here.  This problem occurs because Asterisk assumes that during a
re-invite, the media formats will not change from the original sdp offer. 
In this case, this assumption is wrong, thus you receive the wrong codec. 
I am not saying this is not a bug in Asterisk, I am saying your
understanding of what you have observed is wrong. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-03-09 09:54 mnicholson     Note Added: 0101381                          
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