[asterisk-bugs] [Asterisk 0016755]: E1 PRI channel 'glare', where asterisk hangups up the inbound call from network.

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16755 
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Reported By:                alecdavis
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16755
Category:                   Channels/chan_dahdi
Reproducibility:            random
Severity:                   minor
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           SVN 
JIRA:                       SWP-842 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): 1.6.1 
SVN Revision (number only!): 243988 
Request Review:              
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Date Submitted:             2010-02-02 13:24 CST
Last Modified:              2010-02-04 00:11 CST
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Summary:                    E1 PRI channel 'glare', where asterisk hangups up
the inbound call from network.
Description: 
randomly we are experiencing an ISDN 'glare'.

Captures caught so far have been our IVR dialing back out to the PSTN, at
exactly the same time an incoming network call arrives.

The issue is, asterisk hangs up on the inbound call from the network, that
has the channel set to exclusive, where the outbound call has only
requested a preferred channel, which later is assigned to another channel
in the SETUP ACKNOLEDGE.

Looks like we have outbound precedence in a 'glare' situation, when really
the inbound call is probably more important.
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 (0117693) wimpy (reporter) - 2010-02-04 00:11
 https://issues.asterisk.org/view.php?id=16755#c117693 
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First case

The situation:
Here we have both ends trying to claim the same channel at the same time.
* sends a setup with X as the preferred channel and then receives a setup
with X a the exclusive channel.
Note: The was no setup ack for the sent setup.

What happens:
* rejects the received setup because the requested channel is in use.

What should happen:
* should note that it only TRIED to claim the channel but it's not
negotiated yet. So effectively the channel is still free and the received
setup should be acknowledged.
Just the try to claim the channel via the sent setup failed. But that
issue will be handled by the other end. (which is in fact successfully done
here) 

Issue History 
Date Modified    Username       Field                    Change               
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2010-02-04 00:11 wimpy          Note Added: 0117693                          
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