[asterisk-bugs] [Asterisk 0012713]: SIP Protocol Violation when REFER rejected in sip_transfer (Cisco CCM, post answer), and Transfer application misclaims success.

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=12713 
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Reported By:                davidw
Assigned To:                
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Project:                    Asterisk
Issue ID:                   12713
Category:                   Channels/chan_sip/Transfers
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.4.20 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             05-23-2008 12:59 CDT
Last Modified:              06-04-2008 10:00 CDT
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Summary:                    SIP Protocol Violation when REFER rejected in
sip_transfer (Cisco CCM, post answer), and Transfer application misclaims
success.
Description: 
A call from Cisco CCM was answered and then transferred back to a different
extension on the Cisco.

Asterisk first reported a successful TRANSFERSTATUS, then tried to use a
REFER method.  This was rejected as unsupported.  Asterisk responded with
BYE, which the Cisco accepted.  However it continued to try to send REFERs,
which the Cisco, of course, rejected, because the session reference had
been deleted by the BYE!
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---------------------------------------------------------------------- 
 putnopvut - 06-04-08 10:00  
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I believe this issue is occurring because of Asterisk's inflexibility for
supporting multiple transactions within a dialog. The REFER is sent with
Cseq 102.  Before the response is received, Asterisk sends a BYE with Cseq
103. When the response for the REFER is received, Asterisk sees that the
Cseq is less than the latest Cseq sent for that dialog, and so Asterisk
does not handle the response at all. If you have sip history enabled, you
would probably see a lot of messages that say "Ignoring this retransmit."

This is similar to issue http://bugs.digium.com/view.php?id=10052 (which is now
closed) and issue http://bugs.digium.com/view.php?id=11848,
which suffer similar consequences due to the same behavior. 

Issue History 
Date Modified   Username       Field                    Change               
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06-04-08 10:00  putnopvut      Note Added: 0087802                          
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