Urgent! IP Phone every day needs to plug in the netwowk cable

Dear All
i have strange problem
I have call M in the Data Center and Remote Site with two Lines 2M each.
the IP Phone in the remote Site 7975 with Expansion Module 7916 needs to plug
out and plug in the network cable to work.
this happens every day morning.
1-the switches are Nortel and PoE
2- we have installed Firewall in the Datacenter recently (FortiGate)
3- the IP Phone from the same kind and with same Expansion Module doesnt face
this problem it is behind the firewall

do u think the problem is from
a- the nortel switches in the remote site
b- the fireall
Received on Sun Feb 14 2010 - 09:21:18 ART