[asterisk-bugs] [Asterisk 0012548]: SIP channel protocol illegally reverses direction when ringing channel AMI redirected (to parked channel)

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=12548 
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Reported By:                davidw
Assigned To:                oej
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Project:                    Asterisk
Issue ID:                   12548
Category:                   Channels/chan_sip/General
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     assigned
Asterisk Version:           SVN 
SVN Branch (only for SVN checkouts, not tarball releases):  1.4  
SVN Revision (number only!): 11463 
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             04-29-2008 09:47 CDT
Last Modified:              05-15-2008 11:28 CDT
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Summary:                    SIP channel protocol illegally reverses direction
when ringing channel AMI redirected (to parked channel)
Description: 
An outgoing call to a SIP channel was initiated using AMI Originate; the
first channel was a Local/ channel.  Whilst the call was still ringing, the
Local channel was AMI Redirected to a parked channel in the parking lot
(and drops out of the configuration).  A short time later, the call fails
within Asterisk, with the following diagnostics:

[Apr 27 11:09:03] WARNING[10117]: chan_sip.c:1948 retrans_pkt: Maximum
retries e
xceeded on transmission 4dd8e816320e6fac293336971fb18544 at 192.168.130.116
for seq
no 102 (Critical Response)
[Apr 27 11:09:03] WARNING[10117]: chan_sip.c:1972 retrans_pkt: Hanging up
call 4
dd8e816320e6fac293336971fb18544 at 192.168.130.116 - no reply to our critical
packe
t.

The destination phone continues to ring for some time after this.

If the call is answered before the Redirect, there is no problem.

Looking at the SIP traces indicates that Asterisk starts sending OK's (for
NOTIFY) in the same direction as it sent the NOTIFY's for the call setup. 
The called end ignores these.  If it answers after Asterisk has abandoned
it, it Asterisk ignores its OK's, in the correct direction, resulting in
the phone timing out before it considers the call dead.

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---------------------------------------------------------------------- 
 davidw - 05-15-08 11:28  
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Can I stress that although this originally manifested as a SIP protocol
error, it is really a couple of problems with masquerading:

1) the outgoing status of a channel gets lost;
2) indications are lost/not re-instated properly on the new destination.

As an example of point (2), we worked round point (1), without a code
change, by interposing a Local channel, that would optimise out when the
call completed.  When the incoming side of this Local channel is redirected
to the parked call, the music on hold for the parked call is replaced by
silence, until the the other party actually answers.  The SIP channel is no
longer directly involved in the masquerade, so the protocol does not get
confused. 

Issue History 
Date Modified   Username       Field                    Change               
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05-15-08 11:28  davidw         Note Added: 0086913                          
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