asterisk users - Sep 2006 - High utilization with SIP registration

Greetings all,

I have a problem with a PBX that I manage.  The system has 2 AVM Fritz boards
connected to two BRI ISDN services using chan_capi in addition to several SIP
trunks going out to Internet based providers for call termination via the
Internet.

They experience problems when the Internet connection goes down.  Obviously the
SIP trunks are lost.  However the strange thing is that calls are dropped on
the capi channels as well during these Internet outages.

One of the engineers that I work with felt that the problem was due to Asterisk
persistantly trying to re register the SIP services and was  using up too much
CPU in the process.  In fact he was able to workaround the problem temporarily
by commenting out the SIP registration in sip.conf, which would confirm his
theory.

I suppose my question is.  Has anyone else seen this sort of behaviour before? 
Is there any SIP settings that we should be including to try to slow down the
SIP registration so that it doesn't use up too many system resources?

----------------------------------------------------------------
This message was sent using MyMail