Calls being blocked on SIP Trunk

[Ronaldo Lino dos Santos]

Here at the company we have a CUCM cluster in version 11.5, with 02 ISR 2951 gateways installed, one at the headquarters (Area 21) and the other at the branch (Area 11).

CUCM routes work with redundancy.

When someone from head office makes a call, it goes to the head office gateway. When the call cannot be completed due to an unavailable link, CUCM directs the call to the branch gateway.

We handle calls so that they follow the lowest cost path.

When a user from head office (area 21) makes a call to a number in area 11, the call is directed primarily to the branch gateway (area 11) and if it cannot reach the gateway in area 11, it is directed to the area 21 gateway.

From time to time, all calls from head office users are being directed only to the head office gateway.

When I apply the reset to the SIP trunk of the branch gateway, the calls work again for a while, but then they are blocked.

When I restart Publisher, which is installed in the matrix, the routes work normally again, until Publisher starts working again.

Can anyone help me with this problem?

[Maren Mahoney]

When you are at the point where you are resetting the SIP Trunk, what is it's status? Does is show "Full Service" or "Partial Service"? (I'm assuming you have SIP Options PING enabled on the SIP Profile for the trunks.)

What I would suggest is gathering trace files for a failed call (or looking in RTMT at the real time data for your SIP calls) to determine the reason the call is not flowing through the secondary SIP Trunk. That will help us pinpoint why the secondary SIP Trunk is needing the reset to bring it back into full service. You can also view the debug ccsip messages information on the router for that same call and see how it is attempting to process it.

Please gather the trace and debug and attach it to a reply to this post as a TXT file (avoiding pasting the output in to the window...it makes it hard for us to read) and we can go from there.

Maren