[asterisk-bugs] [Asterisk 0014611]: [patch] SIP Attended Transfer fails

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=14611 
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Reported By:                klaus3000
Assigned To:                
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Project:                    Asterisk
Issue ID:                   14611
Category:                   Channels/chan_sip/Interoperability
Reproducibility:            have not tried
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.4.23 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-03-05 11:10 CST
Last Modified:              2009-03-06 07:08 CST
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Summary:                    [patch] SIP Attended Transfer fails
Description: 
Hi!
The attended trasfer fails in the following scenario:
PBX: Aterisk 1.4.23
Extensions: 1, 2 and 3

Extension 2 call extension 1. 
Extension 1 puts extension 2 on hold.
Extension 1 calls extension 3.
Extension 1 put extensions 3 on hold.
Extension 1 refers extension 3 to extension 2  

--> Asterisk sends NOTIFY with message/sipfrag:
  SIP/2.0 481 Call leg/transaction does not exist

and the transfer fails.

The failure happens only if the REFER is sent to extension 3. If
extensions 1 refers extension 2 to extension 3, then everything works
fine.

I have tested with recent SNOM and eyebeam clients - same result, transfer
does not work. 




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 (0101303) klaus3000 (reporter) - 2009-03-06 07:08
 http://bugs.digium.com/view.php?id=14611#c101303 
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Attached patch fixes the bug. The problem is that Asterisk changed compared
wrong tags for outgoing calls. This is wrong, as the RFC states: 

> In other words, the to-tag parameter is compared to the local
> tag, and the from-tag parameter is compared to the remote tag.

There is no difference if a call is incoming or outgoing - the local tag
should always be compared to the to-tag. Trunk also uses the wrong logic
and needs to be fixed.

btw: attended transfer tested and works now fine in all scenarios
(incoming, outgoing calls) with eyebeam and SNOM phones. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-03-06 07:08 klaus3000      Note Added: 0101303                          
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