21-12
Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
78-11380-10
Chapter21 Configuring IGMP Snooping and MVR
Configuring IGMP Snooping
Note We strongly recommend that you do not disable IP multicast-source-only learning. IP
multicast-source-only learning should be disabled only if your ne twork is n ot c om posed of IP
multicast-source-only networks and if disabling this learning method improves the network
performance.
Beginning in privileged EXEC mode, follow these steps to disable IP multicast-source-only learning:
To enable IP multicast-source-only learning, use the ip igmp snooping source-only-learning global
configuration command. To enable PIM v2 multicast router discovery, use the p igmp snooping
mrouter learn pim v2 global configuration command.
This example shows how to disable IP multicast-source-only learning and PIM v2 multicast router
discovery:
Switch# configure terminal
Switch(config)# no ip igmp snooping source-only-learning
Switch(config)# no ip igmp snooping mrouter learn pim v2
Switch(config)# end
Configuring the Aging Time
You can set the aging time for forwarding-table entries that the switch learns by using the IP
multicast-source-only learning method.
Beginning in privileged EXEC mode, follow these steps to configure the aging time:
Command Purpose
Step1 configure terminal Enter global configuration mode
Step2 no ip igmp snooping source-only-learning Disable IP multicast-source-only learning.
Step3 no ip igmp snooping mrouter learn pim v2 (Optional) Disable multicast router discovery by PIM v2
packets.
Step4 end Return to privileged EXEC mode.
Step5 show running-config | include
source-only-learning Verify that IP multicast-source-only learning is disabled.
Step6 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 source-only learning age-timer
time Set the aging time. The range is from 0 to 2880 seconds. The
default is 600 seconds (10 minutes).
Step3 end Return to privileged EXEC mode.
Step4 show running-config | include
source-only-learning Verify the aging time.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.