24-34
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-03
Chapter 24 Configuring IP Multicast Routing
Configuring Optional IGMP Features
Configuring the Multilayer Switch as a Member of a Group
Multilayer switches can be configured as members of a multicast group. This is useful to determine
multicast reachability in a network. If all the multicast-capable routers and multilayer switches that you
administer are members of a multicast group, pinging that group causes all these devices to respond. The
devices respond to ICMP echo-request packets addressed to a group of which they are members. Another
example is the multicast trace-route tools provided in the Cisco IOS software.
Beginning in privileged EXEC mode, follow these steps to configure the multilayer switch to be a
member of a group:
To cancel membership in a group, use the no ip igmp join-group group-address interface configuration
command.
This example shows how to allow the switch to join multicast group 255.2.2.2:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ip igmp join-group 255.2.2.2
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and specify the interface to be
configured.
Step 3
ip igmp join-group group-address
Configure the switch to join a multicast group.
By default, no group memberships are defined.
For group-address, specify the multicast IP address in dotted decimal
notation.
Step 4
end
Return to privileged EXEC mode.
Step 5
show ip igmp interface [interface-id]
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.