When connecting OCS and Nortel CS1000 you can run in to problem regarding your patch level on the CS1000.
Please be sure that your Cs1000 has installed all the right Patches, use the “dep list” from Nortel
I had a problem here regarding a customer that’s has a running OCS/CS1000 enviroment, but suddenly some problem started accruing after CS1000 patch install.
The MCM log had stuff like this:
MediationServer 503/504 handler: there is no "sip-gw-id" parameter in the stored INVITE
”504 server time out” and ”no sip-gw-id”.
ProcessRequestFromGateway: there is no "sip-gw-id" parameter in the incoming INVITE
The problem is no/missing sip-gw-id in the invite.
Working (incl sip-gw-id):
To fix this, you need the SigServer patch p25226_1.spm it was disabled after installing and other patch.