[asterisk-bugs] [Asterisk 0018119]: Reregistration with small (20 sec) Expiry fails

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18119 
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Reported By:                fabled
Assigned To:                
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Project:                    Asterisk
Issue ID:                   18119
Category:                   Channels/chan_sip/Registration
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     new
Asterisk Version:           1.6.2.13 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-10-12 03:36 CDT
Last Modified:              2010-10-12 07:13 CDT
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Summary:                    Reregistration with small (20 sec) Expiry fails
Description: 
Apparently the following happens:

1. Asterisk register succesfully, 20s Expiry -> reregister in 15s
   - destruction of sip_pvt scheduled with timeout > 15s
2. When reregister triggers:
   - sip_registry->call is NULL, because of successful registration
   - transmit_register builds new sip_pvt with same call ID as
https://issues.asterisk.org/view.php?id=1
3. Server replies
4. Asterisk rejects registration reply because:
   - the sip_pvt from https://issues.asterisk.org/view.php?id=1 has not been yet
destroyed
   - and asterisk routes the reply to sip_pvt from
https://issues.asterisk.org/view.php?id=1 due to call-id
conflict
   - this is indicated by log messages such as:
[Oct 11 21:34:26] DEBUG[16751] chan_sip.c: Ignoring out of order
response 476 (expecting 475)
   - until we get timer_t1*64 ms later the message
[Oct 11 21:34:42] DEBUG[16751] chan_sip.c: Auto destroying SIP dialog
'768de833447ed7e558ee6dcc44f94821 at ...'
   - immediately after which the registration succeeds again

Olle suggested on mailing list:
I think it clearly has to do with the t1 timer for
https://issues.asterisk.org/view.php?id=1. It propably hangs
around for more than 20 secs. We should set max
T1 for registry transactions to be the expiry time minus some small unit.

And yes, with default global_t1 the timeout would be around 30 seconds.
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 (0127859) schmidts (manager) - 2010-10-12 07:13
 https://issues.asterisk.org/view.php?id=18119#c127859 
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No way on 3. IMO this could cause many dead dialogs in there.
To number 2 i am not sure if this really would be the best way but thats
just a personal opinion.

i would prefer https://issues.asterisk.org/view.php?id=1 cause i was thinking
about the other way, that asterisk
was the registrar not the registering client. In this case it would be ok
to set down the timeout when this sip_pvt should be destroyed. 

BTW who force clients to reregister in 20 seconds and WHY? thats some kind
of nat keep alive for one who doesnt know a better solution ;) 

Issue History 
Date Modified    Username       Field                    Change               
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2010-10-12 07:13 schmidts       Note Added: 0127859                          
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