Hi all. Interesting issue here. I have a question about an issue we are having with our PRI gateways (MGCP 28XX). We've had the same problem on gateways at two different locations registered to two different clusters where inbound calls from the PSTN fail with a fast busy, but outbound calls work. When I do a debug isdn q931, I can see the inbound calls hitting the gateway. The only fix I have found is rebooting the gateway, often a couple of times, and resetting the gateway in Call manager.
I'm wondering if this is an IOS or gateway load issue, since it is happening in both locations on two different clusters; CM in one location is 4.x and the other is 5.x.