[Asterisk-Dev] Asterisk ISDN Channels Restarting

[Peter Svensson]

On Sat, 13 Aug 2005, Richard Doiban wrote:

> Every once in a while I get a message in Asterisk CLI that tells me the
> B-Channels on both my spans have been successfully restarted.
> 
> I'm really not sure what is happening here except that I know it drops any active calls. I'm also not sure of what model of digium card I have, but I do know its a 4-port digium T1 card. Its setup as esf, b8zs.
> Does anyone know what this can be attributed to?

Asterisk requests an isdn restart on all inactive B channels once every
hour by default. This is done to resynchronize the signalling state
machines on the local and remote isdn devices.

Whether this is a standards compliant or not has been up for debate
several times with no consensus. If you experience problems then by all 
means disable this feature as described in Jeremy McNamara's email. 

The remote end is certainly not allowed to drop any calls on non-requested 
B channels. Still, some implementations such as the Panasonic PRI card for 
the KX-TD1232 do restart _all_ channels, not just the requested ones.

Peter