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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter11 Configuring IGMP Snooping and M VR Configuring IGMP Snooping
Beginning in privileged EXEC mode, follow these steps to alter the method in which a VLAN interface
dynamically accesses a multicast router:
This example shows how to configure IGMP snooping to use CGMP packets as the learning method:
Switch# configure terminal
Switch(config)# ip igmp snooping vlan 1 mrouter learn cgmp
Switch(config)# end
Switch# show ip igmp snooping vlan 1
vlan 1
----------
IGMP snooping is globally enabled
IGMP snooping is enabled on this Vlan
IGMP snooping immediate-leave is disabled on this Vlan
IGMP snooping mrouter learn mode is cgmp on this Vlan
IGMP snooping is running in IGMP_ONLY mode on this Vlan
To return to the default learning method, use the no ip igmp snooping vlan vlan-id mrouter learn cgmp
global configuration command.
Configuring a Multicast Router Port
To add a multicast router port (add a static connection to a multicast router), use the ip igmp snooping
vlan mrouter global configuration command on the switch.
Note Static connections to multicast routers are supported only on switch ports.
Beginning in privileged EXEC mode, follow these steps to enable a static connection to a multicast
router:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 ip igmp snooping vlan vlan-id mrouter
learn {cgmp | pim-dvmrp}Enable IGMP snooping on a VLAN. The VLAN ID range is 1 to 1001.
Specify the multicast router learning method:
cgmpListen for CGMP packets. This method is useful for
reducing control traffic.
pim-dvmrpSnoop on IGMP queries and PIM-DVMRP
packets. This is the default.
Step3 end Return to privileged EXEC mode.
Step4 show ip igmp snooping Verify the configuration.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 ip igmp snooping vlan vlan-id mrouter
interface interface-id Specify the multicast router VLAN ID (1 to 1001), and specify
the interface to the multicast router.
Step3 end Return to privileged EXEC mode.