I just started with a new company and inherited an issue where call setup is not working to a particular location. As soon as the called party answers, the call drops.

Here's the logical diagram:

Calls terminate successfully this way --

Site A >> PRI >> PSTN >> PRI >> Site B

Call setup fails this way --

Site A >> PRI >> PSTN >> PRI >> Site B >> ICT >> Site C

So basically I can complete calls to Site B, but not to site C -- call setup fails.

I only have insight from Site A to the PSTN, and the admin at Site B says the issue is on my side. This looks like a resource issue on their side to me. I am not skilled enough to find damning evidence in trace logs but did gather both a ccapi inout and Q.931 debug on the gateway -- MGCP signaling.

Please offer up any assistance. Thank you!