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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter11 Configuring IGMP Snooping and M VR Displaying IGMP Snooping Information

Enabling IGMP Immediate-Leave Processing

When you enable IGMP Immediate-Leave processing, the switch immediately removes a port when it
detects an IGMP version 2 leave message on that port. You should use the Immediate-Leave feature on ly
when there is a single receiver present on every port in the VLAN.
Immediate Leave is supported with only IGMP version 2 h osts.
Beginning in privileged EXEC mode, follow these steps to enable IGMP Immediate-Leave processing:
To disable IGMP Immediate-Leave on a VLAN, use the no ip igmp snooping vlan vlan-id
immediate-leave global configuration command.
This example shows how to enable IGMP immediate-leave pr ocessi ng on VL AN 130 and ve rif y the
configuration:
Switch# configure terminal
Switch(config)# ip igmp snooping vlan 130 immediate-leave
Switch(config)# end
Switch# show ip igmp snooping vlan 130
vlan 130
----------
IGMP snooping is globally enabled
IGMP snooping is enabled on this Vlan
IGMP snooping immediate-leave is enabled on this Vlan
IGMP snooping mrouter learn mode is pim-dvmrp on this Vlan
IGMP snooping is running in IGMP_ONLY mode on this Vlan
Displaying IGMP Snooping Information
You can display IGMP snooping information for dynamically learned and statical ly c onf igur ed rout er
ports and VLAN interfaces. You can also display MAC add ress multicast entries for a VLAN con figured
for IGMP snooping.
To display IGMP snooping information, use one or more of the privilege d E XEC c om mands in
Table11-4.
Command Purpose
Step1 configure terminal Enter global configuration mode
Step2 ip igmp snooping vlan vlan-id
immediate-leave Enable IGMP Immediate-Leave processing on the VLAN interface.
Step3 end Return to privileged EXEC mode.
Step4 show ip igmp snooping vlan vlan-id Verify that Immediate Leave is enabled on the VLAN.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.