I was thinking of isolating the network to test. I have not yet. One interesting thing is that when the phones are down, I can ping them from the IP Office, so they are still technically up, and the IP Office can see them on the network, they just unregister. I try and reregister and reset the phones from Monitor/SIP, but it doesn't do anything. I have an engineering case open with Avaya. Hopefully they can figure this one out.