Chapter 9
Configuring Multicast Routing
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Disabling IGMP on an Interface
You can disable IGMP on specific interfaces. This is useful if you know that you do not have any
multicast hosts on a specific interface and you want to prevent the FWSM from sending host query
messages on that interface.
To disable IGMP on an interface, enter the following command:
hostname(config-if)# no igmp
To reenable IGMP on an interface, enter the following command:
hostname(config-if)# igmp
Only the no igmp command appears in the interface configuration.
Note
Configuring Group Membership
You can configure the FWSM to be a member of a multicast group. Configuring the FWSM to join a
multicast group causes upstream routers to maintain multicast routing table information for that group
and keep the paths for that group active.
To have the FWSM join a multicast group, enter the following command:
hostname(config-if)# igmp join-group group-address
Configuring a Statically Joined Group
Sometimes a group member cannot report its membership in the group, or there may be no members of
a group on the network segment, but you still want multicast traffic for that group to be sent to that
network segment. You can have multicast traffic for that group sent to the segment in one of two ways:
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To configure a statically joined multicast group on an interface, enter the following command:
hostname(config-if)# igmp static-group group-address
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
OL-20748-01
Controlling Access to Multicast Groups, page 9-4
Limiting the Number of IGMP States on an Interface, page 9-4
Modifying the Query Interval and Query Timeout, page 9-4
Changing the Query Response Time, page 9-5
Changing the IGMP Version, page 9-5
Using the igmp join-group command (see
the FWSM to accept and to forward the multicast packets.
Using the igmp static-group command. The FWSM does not accept the multicast packets but rather
forwards them to the specified interface.
Configuring Group Membership, page
Configuring IGMP Features
9-3). This causes
9-3