No subject

600
I'm subscribed to a "buddy" on my Polycom phone. Periodically I'd get this
error: 'Incoming call: Got SIP response 500 "Internal Server Error" back
from 10.1.1.200'.

Additional Description

We have six(6) Polycom 601 attenendant consoles monitoring roughly
forty(40) Polycom 430 phones each for a total of one hundred (100) or so
watchers/hints.

To reproduce the behaviour you need only interrupt chan_sip via reload, or
an Asterisk restart.  Once this has been done, presence notifications sent
to the phones will no longer take place properly.  It is unclear as to
whether this problem is due to the Asterisk system not sending the right
messages, or the Polycom not responding properly to a properly formatted
message.  But, after a while, the phones will start sending messages back
in response to messages from Asterisk that say "Internal Server Error". 
One thing is for certain.  After the channel is interrupted, by reload or
restart, presence no longer works.
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---------------------------------------------------------------------- 
 mlegas - 09-25-07 04:53  
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I can confirm the same issue with Thomson ST2030 SIP phones 
Whenever Asterisk is restarted, thomson phones loose their subscriptions.
It is needed to restart them to get it working again.
We can monitor that they are sending subscriptions requests every 30
minutes (before their expiration) which are acknowledged by Asterisk but
then when they received NOTIFY they answer with Internal Server Error.
After investigation it seems related to the field CSeq in SIP. After a
restart CSeq starts over and the thomson phone does not seem to like it.

Snom phones do not have this problem !
so it could be a phone problem in fact. 

Issue History 
Date Modified   Username       Field                    Change               
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09-25-07 04:53  mlegas         Note Added: 0071057                          
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