Using Cisco CallManager on the Integrated Communications System (ICS) 7750 platform requires configuration for getting a D channel working while doing PRI backhaul to Cisco CallManager. This sample trace from the gateway helps define the problem:
*Mar 8 13:15:43.119: send_mgcp_msg, MGCP Packet
sent to 10.1.1.6:2427 --->*Mar 8 13:15:43.119: RSIP 1 *@MRP1 MGCP
0.1RM: restart<---*Mar 8 13:15:47.119: send_mgcp_msg, MGCP Packet
sent to 10.1.1.6:2427 --->*Mar 8 13:15:47.119: RSIP 1 *@MRP1 MGCP
0.1RM: restart<---*Mar 8 13:15:51.119: send_mgcp_msg, MGCP Packet
sent to 10.1.1.6:2427 ---> *Mar 8 13:15:51.119: RSIP 1 *@MRP1 MGCP
The trace from the gateway indicates the gateway is sending packets. However, nothing comes back to the gateway as a reply. With this information, and the fact that this is an Media Gateway Control Protocol (MGCP) gateway, the configuration of the gateway inside of Cisco CallManager needs to be addressed.
Inside Cisco CallManager, the gateway is not registered. The domain name in Cisco CallManager for the gateway did not match exactly the host name of the router.
Delete the existing gateway configuration from Cisco CallManager, and create a new one, ensuring that the domain name entered for the MGCP gateway matches the host name of the router. Once the host name of the router matches the domain name entered in Cisco CallManager, everything works as expected.