Sometimes strange things happen after a power failure.
For example one of our Cisco 2801 Router with Voice capabilities had suddenly shutdown.
Normally, this would not happen because it is connected to a UPS, but this brand new store had not opened yet and the UPS had not been placed yet.
So, after the power had returned the router came up, and even registered correctly to the Call Manager at the HQ.
Internal calls could be made, calls could be made to the HQ and other stores over the trunk and even calls from outside the store could be answered.
The only thing that did not work was creating calls outside the store.
After debugging the isdn30 interface with the debug isdn q931 command I noticed none of the calls were actually routed over the ISDN network.
So it had to be something in the call manager, as this device decides where to route a call.
The solution was resetting the route-list of the store. After resetting it, all calls where routed normally.
In normal conditions, where the gateway would be gracefully reset by a “reload” command this would not have happend…