4 igmp snooping troubleshooting – PLANET WGSW-50040 User Manual

Page 166

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PIM-SM on ROUTER, and enable PIM-SM on vlan 100 (use the same PIM mode with the connected multicast

router)

Configurations are listed as below:

switch#config

switch(config)#ip pim multicast-routing

switch(config)#interface vlan 100

switch(config-if-vlan100)#ip pim sparse-mode

IGMP snooping does not distribute entries when layer 3 multicast protocol is enabled. It only does the

following tasks.

Remove the layer 2 multicast entries.

Provide query functions to the layer 3 with vlan, S, and G as the parameters.

When layer 3 IGMP is disabled, re-enable distributing layer 2 multicast entries.

By looking up the layer 3 IPMC entries, it can be found that ports can be indicated by the layer 3 multicast

entries. This ensures the IGMP snooping can work in cooperation with the layer 3 multicast protocols.

21.3.4 IGMP Snooping Troubleshooting

On IGMP Snooping function configuration and usage, IGMP Snooping might not run properly because of

physical connection or configuration mistakes. So the users should note that:

Make sure correct physical connection

Activate IGMP Snooping on whole configuration mode (use ip igmp snooping)

Configure IGMP Snooping at VLAN on whole configuration mode ( use ip igmp snooping vlan

<vlan-id>)

Make sure one VLAN is configured as L2 common checker in same mask, or make sure configured

static mrouter

Use show ip igmp snooping vlan <vid> command check IGMP Snooping information

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