[asterisk-users] pjsip: occasional sip_transactio Unable to register REGISTER transaction (key exists)

[Michael Maier]

On 06/06/2016 at 04:40 PM, Richard Mudgett wrote:
> On Sun, Jun 5, 2016 at 3:48 AM, Michael Maier <m1278468 at allmail.net> wrote:
> 
>> Hello!
>>
>> I occasionally can see warnings like these during *idle* times in
>> asterisk log (asterisk 13.7.2):
>>
>> [2016-06-05 06:11:51] WARNING[27817] pjsip:     sip_transactio Unable to
>> register REGISTER transaction (key xists)
>> [2016-06-05 06:11:51] WARNING[27817] pjsip:     sip_transactio Unable to
>> register REGISTER transaction (key exists)
>>
>> Nothing more. The third REGISTER package works as expected.
>>
>>
>> What's going on:
>> My phone regularly (each 7.5 minutes) sends REGISTER. Sometimes, those
>> REGISTERs are denied like seen above (mostly already the second REGISTER
>> works and no third REGISTER is needed).
>>
>> The reRegistering of the phone normally works like this (as seen in
>> wireshark):
>>
>> -> REGISTER                             06:04:19:285
>> <- 401 Unauthorized                     06:04:19:287
>> -> REGISTER                             06:04:19:316
>> <- 200 OK                               06:04:19:376
>>
>>
>> If warnings happen like the one mentioned above, the following can be
>> seen in wireshark:
>>
>> -> REGISTER                             06:11:49:359
>> <- 401 Unauthorized                     06:11:49:362
>> -> REGISTER                             06:11:49:392    Unable ...
>> -> REGISTER                             06:11:49:876    Unable ...
>> -> REGISTER                             06:11:50:868
>> <- 200 OK                               06:11:51:634
>>
>> The second, third and fourth register package look completely identical
>> to me according wireshark regarding SIP.
>>
>> Notice the big latency between the fourth register and the following 200
>> OK: there are nearly 0.8 seconds in between in the problem case - but
>> normally, there are just 0.06 seconds between REGISTER and 200 OK!
>>
>> What happened during these 0.8 seconds? Asterisk (and the complete
>> machine) has been completely idle at this time - there wasn't any call
>> or anything other to process.
>>
>> I've got the complete wireshark trace of the situation described above.
>>
> 
> Those key exist messages are due to a race condition.  From what I've

It should be impossible - there couldn't be any race condition at this time.

> seen in the code the messages seem to be benign.
> 
> How may endpoints are registering to your Asterisk?

1 device, which registers 2 different numbers *serially*. Asterisk
didn't do any other things at the time those warnings came up. It was
idle. Completely.

> How often?

Each 7.5 minutes.

> Do you use realtime? 

No.


Regards,
Michael