Backbone terminates after 240 seconds on isolated node

I am doing some testing on an AutoStart pair running on Windows 2003 sp1. When I isolate one of the nodes completely so that the isolation script reboots the box, the backbone terminates in 240 seconds after reboot if the node remains isolated. If I reconnect a network cable, then the node comes online as it should.

I have enabled logging and I can see that the backbone services comes on-line and repeatedly pings the isolation addresses as it should. However, it seems to take itself offline gracefully after 240 seconds. The system event log for the service control manager is showing that the backbone service signaled that it would be entering the stopped state so the service manager does not mind that the service is shutting down.

I was expecting the backbone service to continuously ping the isolation addresses until one of them responded. Then it will bring the agent on-line and the node will come up. This is what happens if I replace any of the network connections before the 240 seconds elapses.

Is this the correct behavior?

Thanks much,
Dave.
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