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.
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
ip igmp join-group group-address
Step 4
end
show ip igmp interface [interface-id]
Step 5
Step 6
copy running-config startup-config
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
Step 1
configure terminal
Step 2
interface interface-id
Step 3
ip igmp access-group access-list-number
Step 4
exit
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
48-40
Purpose
Enter global configuration mode.
Specify the interface to be configured, and enter interface configuration
mode.
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.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Specify the interface to be configured, and enter interface
configuration mode.
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.
Return to global configuration mode.
Chapter 48
Configuring IP Multicast Routing
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