/mcpMulticast RouterEnable IP multicasting (global command):ip multicast-routingEnable each interface running CGMP (interface mode) with the following commands:ip pim <sparse- mode/dense-mode>ip igmpip cgmpDebug the L2 multicast problem with the following commands:debug ip igmpdebug ip cgmp G Catalyst 4000 or 5000 seriesEnable/disable CGMP with the following commands:set cgmp <enable/disable>Enable/disable CGMP Fast-Leave with the following commands:set cgmp leave <enable/disable>Configure the multicast router (static) with the following commands:set multicast router <slot /port>Clear the multicast router with the following commands:clear multicast router <slot/port>Listed below are various commands to verify the CGMP operation.show cam staticshow cgmp statistic <VLAN_id>show cgmp leaveshow multicast routershow multicast groupshow multicast group cgmpshow multicast group count G Practical Example of CGMP Use and Debug Command and Output This is a practical configuration example for a Cisco router and Catalyst switches. This configuration shows the operations involved as a host joins a group. This configuration alos shows the operations as a host leaves a group with Fast-Leave enabled. Sniffer traces and the configuration of the switch and the router are also provided. Joining a Group with CGMP Refer to these steps when joining a group with CGMP. Enable CGMP on the switch, as shown below. Switch_B (enable) set cgmp en MCAST-CGMP: Set CGMP Sys Entrie MCAST-CGMP: Set CGMP Sys Entrie MCAST-CGMP: Set CGMP Sys Entrie CGMP support for IP multicast enabled. Switch_B (enable) As you can see below, the entry 01-00-0c-dd-dd-dd is included for all VLANs in the show cam system command output. In addition, as the network is running CGMP Fast-Leave, you can see the entries for 01-00-5e-00-00-01 and 01-00-5e-00-00-02. Switch_B (enable) show cgmp leave CGMP: enabled CGMP leave: enabled Switch_B (enable) show cam system
1 00-10-2f-00-14-00 # 7/1 1 00-e0-fe-4b-f3-ff # 1/9 1 01-00-0c-cc-cc-cc # 1/9 1 01-00-0c-cc-cc-cd # 1/9 1 01-00-0c-dd-dd-dd # 1/9 1 01-00-0c-ee-ee-ee # 1/9 1 01-80-c2-00-00-00 # 1/9 1 01-80-c2-00-00-01 # 1/9 1.