48-40
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 48 Configuring IP Multicast Routing
Configuring Optional IGMP Features
Beginning in privileged EXEC mode, follow these steps to configure the switch to be a member of a
group. This procedure is optional.
To cancel membership in a group, use the no ip igmp join-group group-address interface configuration
command.
This example shows how to enable the switch to join multicast group 255.2.2.2:
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip igmp join-group 255.2.2.2
Controlling Access to IP Multicast Groups
The switch sends IGMP host-query messages to find which multicast groups have members on attached
local networks. The switch then forwards to these group members all packets addressed to the multicast
group. You can place a filter on each interface to restrict the multicast groups that hosts on the subnet
serviced by the interface can join.
Beginning in privileged EXEC mode, follow these steps to filter multicast groups allowed on an
interface. This procedure is optional.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the interface to be configured, and enter interface configuration
mode.
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.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the interface to be configured, and enter interface
configuration mode.
Step 3 ip igmp access-group access-list-number Specify the multicast groups that hosts on the subnet serviced by an
interface can join.
By default, all groups are allowed on an interface.
For access-list-number, specify an IP standard access list number.
The range is 1 to 99.
Step 4 exit Return to global configuration mode.