We're experiencing a really weird issue.
The setup consists on a 2811 working as H323 gateway with an E1 R2-Digital line and 2 MCS servers running Cisco UCM 7.1.2.
Since friday any calls have been working fine, what's happening now is that SUDDENLY none will be able to place outside calls or to receive calls comming from PSTN on the E1.
When this happens, calls between IP phones still work fine, as well as calls placed to cell phones, which are being switched to PSTN on cell phone lines connected to the Voice Gateway's FXO ports.
This seem to be something related to the E1 but there aren't any alarms, the E1 is still up too... If I shut then no shut the E1 interface all calls through the E1 will start working again. Which debug I might use to try to find this out ?