[asterisk-bugs] [Asterisk 0016998]: Transfer fails

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16998 
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Reported By:                TimeHider
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16998
Category:                   Channels/chan_sip/Transfers
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           SVN 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 251310 
Request Review:              
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Date Submitted:             2010-03-09 10:16 CST
Last Modified:              2010-05-05 11:13 CDT
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Summary:                    Transfer fails
Description: 
I use transfer button on Cisco Phone with sip firmware, at first push it
calls the person to which I want to transfer the call. When the person
answers and I push transfer button second time, to transfer the call, on
display appear notice that "transfer failed". Both of calls are put onhold.
Transfered person hear lagging music on hold or silence. 
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 (0121426) davidw (reporter) - 2010-05-05 11:13
 https://issues.asterisk.org/view.php?id=16998#c121426 
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The basic way that SIP transfer work is that:

The initial call is set up, in either direction;

The enquriy call is set up, as a completely separate call;

The initial call is sent a REFER request, specifying the SIP address used
for the second call and the call ID and other identifying tags for the
second call;

Conceptually the first caller then makes a new call to the number of the
second callee, passing the identifying information for that call;

It also uses NOTIFY requests to forward its progress on that call to the
transferror;

The device on the second line matches up the call identity, and, instead
of starting a new transferred call, joins the two calls together;

The two remote parties then send BYEs to the the transferror.

Because you are not talking directly to the two remote parties, but
actually to Asterisk, the call following the REFER happens purely
internally in Asterisk, although the NOTIFYs are still generated.

In this case, the NOTIFY is saying that the "remote" end of internal call
failed to match the call id and other information against any call, even
though it looks to me that a matching call is still in progress. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-05-05 11:13 davidw         Note Added: 0121426                          
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