One of the first steps in troubleshooting an MGCP configuration is to verify that the gateway is registered with the correct CallManager with the command show ccm-manager. The result, as shown in Example 2-1, lists primary and backup CallManagers, in addition to statistics about the connection. Check that the CallManager IP addresses are configured correctly.
[View full width]VGateway#show ccm-manager MGCP Domain Name: VGateway Priority Status Host ============================================================ Primary Registered 10.6.2.10 First Backup Down 10.6.2.11 Second Backup None Current active CallManager: 10.6.2.10 Backhaul/Redundant link port: 2428 Failover Interval: 30 seconds Keepalive Interval: 15 seconds Last keepalive sent: 03:46:22 EST Oct 23 2005 (elapsed time : 00:00:03) Last MGCP traffic time: 03:46:22 EST Oct 23 2005 (elapsed time : 00:00:03) Last failover time: None Last switchback time: None Switchback mode: Graceful MGCP Fallback mode: Not Selected Last MGCP Fallback start time: None Last MGCP Fallback end time: None Configuration Error History: FAX mode: cisco
The show mgcp command gives a long, detailed breakdown of your MGCP configuration. The lines to check in here depend on the type of problem you are having. Some common lines to examine are highlighted in the output of Example 2-2.
[View full width]VGateway#show mgcp MGCP Admin State ACTIVE, Oper State ACTIVE - Cause Code NONE MGCP call-agent: 10.6.2.10 Initial protocol service is MGCP 0.1 MGCP block-newcalls DISABLED MGCP send SGCP RSIP: forced/restart/graceful/disconnected DISABLED MGCP quarantine mode discard/step MGCP quarantine of persistent events is ENABLED MGCP dtmf-relay voip codec all mode out-of-band MGCP dtmf-relay for VoAAL2 disabled for all codec types MGCP voip modem passthrough disabled MGCP voaal2 modem passthrough disabled MGCP voip modem relay: Disabled. MGCP TSE payload: 100 MGCP T.38 Named Signaling Event (NSE) response timer: 200 MGCP Network (IP/AAL2) Continuity Test timer: 200 MGCP 'RTP stream loss' timer: 5 MGCP request timeout 500 MGCP maximum exponential request timeout 4000 MGCP gateway port: 2427, MGCP maximum waiting delay 3000 MGCP restart delay 0, MGCP vad DISABLED MGCP rtrcac DISABLED MGCP system resource check DISABLED MGCP xpc-codec: DISABLED, MGCP persistent hookflash: DISABLED MGCP persistent offhook: ENABLED, MGCP persistent onhook: DISABLED MGCP piggyback msg ENABLED, MGCP endpoint offset DISABLED MGCP simple-sdp DISABLED MGCP undotted-notation DISABLED MGCP codec type g711ulaw, MGCP packetization period 20 MGCP JB threshold lwm 30, MGCP JB threshold hwm 150 MGCP LAT threshold lwm 150, MGCP LAT threshold hwm 300 MGCP PL threshold lwm 1000, MGCP PL threshold hwm 10000 MGCP CL threshold lwm 1000, MGCP CL threshold hwm 10000 MGCP playout mode is adaptive 60, 40, 200 in msec MGCP Fax Playout Buffer is 300 in msec MGCP media (RTP) dscp: ef, MGCP signaling dscp: af31 MGCP default package: line-package MGCP supported packages: gm-package dtmf-package trunk-package line-package hs-package rtp-package atm-package ms-package dt-package res-package mt-package fxr-package MGCP Digit Map matching order: shortest match SGCP Digit Map matching order: always left-to-right MGCP VoAAL2 ignore-lco-codec DISABLED MGCP T.38 Fax is ENABLED MGCP T.38 Fax ECM is ENABLED MGCP T.38 Fax NSF Override is DISABLED MGCP T.38 Fax Low Speed Redundancy: 0MGCP T.38 Fax High Speed Redundancy: 0 MGCP control bind :INACTIVE MGCP media bind :DISABLED MGCP Upspeed payload type for G711ulaw: 0, G711alaw: 8 MGCP Dynamic payload type for G.726-16K codec MGCP Dynamic payload type for G.726-24K codec MGCP Dynamic payload type for G.Clear codec MGCP Guaranteed scheduler time is disabled
If you have made recent changes to the MGCP configuration or its endpoints, stop and start the MGCP process (no mgcp and then mgcp), and then give the show commands again.
The show mgcp endpoint command lists the active endpoints on the gateway. You can also look in CallManager under Device > Gateways > Find and List Gateways to see which endpoints have registered with CallManager. If a voice port is not registered, make sure you have the application mgcpapp command under its dial peer, and that it is configured in CallManager.
Related to this, show voice port gives the status of each port to verify that it is up. If a port is down and the physical connection is good, try shutting and not shutting it, especially with FXS and FXO ports.
You can monitor active calls with the show mgcp connection command. Look for the M (for Mode) field. You should see M=3 if the connection is able to both send and receive traffic.
In addition, you can use the CallManager Performance Monitor and the Cisco Real Time Monitoring Tool (RTMT) to troubleshoot problems with MGCP gateways and endpoints.
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