Cisco Systems 6500, EA6500 Enabling RGMP on Layer 3 Interfaces

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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 22 Configuring RGMP
Enabling RGMP on Layer 3 Interfaces
• The following properties of RGMP are the same as for IGMP snooping:
– RGMP constrains traffic based on the multicast group, not on the sender’s IP address.
– If spanning tree topology changes occur in the network, the state is not flushed as it is with
Cisco Group Management Protocol (CGMP).
– RGMP does not constrain traffic for multicast groups 224.0.0.x (x = 0...255), which allows use
of PIMv2 bootstrap router (BSR) in an RGMP-controlled network.
– RGMP in Cisco network devices operates on MAC addresses, not on IP multicast addresses.
Because multiple IP multicast addresses can map to one MAC address (see RFC 1112), RGMP
cannot differentiate between the IP multicast groups that might map to a MAC address.
– The capability of the Catalyst 6500 series switch to constrain traffic is limited by its
content-addressable memory (CAM) table capacity.
Note With Release 12.1(11b)E and later releases, when you are in configuration mode you can enter EXEC
mode-level commands by entering the do keyword before the EXEC mode-level command.
Enabling RGMP on Layer 3 Interfaces
To enable RGMP on a Layer 3 interface, perform this task:
This example shows how to configure RGMP on FastEthernet port 3/3:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# interface fastethernet 3/3
Router(config-if)# ip rgmp
Router(config-if)# end
Router#
Command Purpose
Step 1 Router(config)# interface {{vlan vlan_ID} |
{type1 slot/port} | {port-channel number}}
1. type = ethernet, fastethernet, gigabitethernet, tengigabitethernet, or ge-wan
Selects an interface to configure.
Step 2 Router(config-if)# ip rgmp Enables RGMP on the Layer 3 interface.
Router(config-if)# no ip rgmp Disables RGMP on the Layer 3 interface.
Step 3 Router(config-if)# end Exits configuration mode.
Step 4 Router# debug ip rgmp [name_or_group_address] (Optional) Monitors RGMP.