Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

8IGMP V2 and V3Brocade# debug ip pim-dvmrp nbr-changenbr 30.30.30.1 phy change from e2/1 to e3/1This output indicates that neighbor 30.30.30.1 has changed from port e2/1 to port e3/1.debug ip pim-dvmrp showSyntax: [no] debug ip pim-dvmrp showThis command displays current debug settings for PIM-DVMRP.Brocade# debug ip pim-dvmrp showdebug ip pim is enabledIGMP V2 and V3The Internet Group Management Protocol (IGMP) allows an IPv4 system to communicate IPmulticast group membership information to its neighboring routers. The routers in turn limit themulticast of IP packets with multicast destination addresses to only those interfaces on the routerthat are identified as IP multicast group members.In IGMP V2, when a router sends a query to the interfaces, the clients on the interfaces respondwith a membership report of multicast groups to the router. The router can then send traffic tothese groups, regardless of the traffic source. When an interface no longer needs to receive trafficfrom a group, it sends a leave message to the router, which in turn sends a group-specific query tothat interface to see if any other clients on the same interface are still active.IGMP V3 provides selective filtering of traffic based on traffic source. A router running IGMP V3sends queries to every multicast-enabled interface at the specified interval. These general queriesdetermine if any interface wants to receive traffic from the router.IGMP show commandsThis section describes the show commands that display IGMP information.show ip igmp groupSyntax: show ip igmp [vrf ] group [ [detail] [tracking]]• vrf - Specifies that you want to display IGMP group information for the VRFspecified.• - Displays a report for a specific multicast group. Omit the parameter for a report for all multicast groups.• detail - Displays the source list of the multicast group.• tracking - Displays information on interfaces that have tracking enabled.This command displays the status of all IGMP multicast groups on a device, as shown in thefollowing example.274 Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide53-1002426-02