Misconfigured dial peers are common problems with H.323 gateways. You can see a list of all the dial peers with the show dial-peer voice summary command. This gives you a summary of the configuration for each dial peer. If you have SRST configured, some dial peers will have high numbers and odd-looking ports. These are the SRST dial peers that the router created. When you are using the nondefault codec, make sure it is defined in the incoming dial peer.
The show dialplan number phone-number command tells which dial peers are matched by a specific phone number.
Several useful debug commands exist. debug cch323 h225 and debug cch323 h245 are good commands to troubleshoot call setup and teardown. You can also use debug h225 and debug h245 commands to troubleshoot call setup and teardown. The debug voip ccapi inout command debugs the call control application programming interface. It shows details about the call setup from both the telephony and network sides. Use the debug ip tcp transaction command to make sure that the TCP session for H.225 and H.245 is being established.
Debugs can be verbose, so log them to the buffer and disable terminal monitoring when you are troubleshooting a gateway that has more than one active call.
You can simulate a phone call from the router with the csim start phone-number command.
View statistics on the H.323 messages sent and received with the show h323 gateway command. You can reset these statistics with the clear h323 gateway command.
Part I: Voice Gateways and Gatekeepers
Gateways and Gatekeepers
Part II: Gateways
Media Gateway Control Protocol
Session Initiation Protocol
Connecting to the PSTN
Connecting to PBXs
Connecting to an IP WAN
Influencing Path Selection
Configuring Class of Restrictions
SRST and MGCP Gateway Fallback
Using Tcl Scripts and VoiceXML
Part III: Gatekeepers
Part IV: IP-to-IP Gateways
Cisco Multiservice IP-to-IP Gateway
Appendix A. Answers to Chapter-Ending Review Questions