[cisco-voip] Nortel 81C / CS1000 SIP Trunk to CUCM 10.5.2

[Michael T. Voity]

Hello,

Before we installed our Cisco CM 10.5.2 system everything here at the 
University is fed from a Nortel Avaya 81c / CS1000 system.   The Telcom 
group has a bunch of systems on it that support SIP and SIP gateways.   
We setup a SIP trunk between the two systems from a guide that Avaya 
provided.   It works fine like 99% of the time.

I am finding that I have to reset the SIP trunk every couple of days 
because it looks like the Nortel is busying out all the channels and it 
can only pass certain traffic.   Example is that someone from Nortel 
land dials a 5 digit extension that has been routed to CUCM, the line on 
CUCM rings once and then discos the call.

Looking at RTMT on the SIP traffic I can tell that the Nortel is sending 
the "BYE" message on the trunk right when the CUCM sends the "RINGING"   
The only way that I have found to correct this is to reset the SIP trunk 
from CUCM.

Has anyone see an issue like this and or heard of this?

Any ideas would be helpful!

-Mike

-- 
Michael T. Voity
Network Engineer
University of Vermont