we are using CUCM 7.1 with 2821 PRI MGCP gateway. all of the sudden PRI was disconnected and lost signaling and then came back up. I got this error from gateway:
005019: Mar 27 18:32:33.422 PDT: %CONTROLLER-5-UPDOWN: Controller T1 0/2/0, changed state to down (10 SES)
005020: Mar 27 18:32:33.426 PDT: ISDN Se0/2/0:23 **ERROR**: handle_l2d_srq_mail: Message tossed, state = 0 spoofing = 0
005021: Mar 27 18:32:33.430 PDT: ISDN Se0/2/0:23 Q931: L3_ShutDown: Shutting down ISDN Layer 3
005022: Mar 27 18:32:33.430 PDT: %ISDN-6-LAYER2DOWN: Layer 2 for Interface Se0/2/0:23, TEI 0 changed to down
005023: Mar 27 18:32:33.438 PDT: %MARS_NETCLK-3-HOLDOVER: Entering Holdover for Controller T1 0/2/0
005024: Mar 27 18:32:35.422 PDT: %LINK-3-UPDOWN: Interface Serial0/2/0:23, changed state to down
I just want to know it's something related to CUCM/Gateway or service provider.
any suggestion would be very appreciated.