I always understood that a phone would switch to it's 2nd choice CallManager when three keepalives that it sent to its primary CallManager were not acknowledged - with keepalives at the default of 30 second intervals that would be a minimun of 60 secs and a max of 90 seconds.
Testing in the lab has shown different behaviour. If I shut down the port on on the switch to which the phones primary CallManager is connected, the phone will re-home to the secondary call manager almost immediatly after the next keepalive that it sends to it's primary which does not get a response.
I've proven this with a sniffer connected to the back on the phone.
Is this a valid test ?