IGMP snooping for a single VLAN

[Vincenzo Santoro]

Hi,

I should enable igmp snooping for just vlan 8 on some Catalyst 3560.

According to the configuration guide: "Global IGMP snooping overrides the VLAN IGMP snooping. If  global snooping is disabled, you cannot enable VLAN snooping. If global  snooping is enabled, you can enable or disable VLAN snooping. "

So, in order to enable igmp snooping on vlan 8, I should use the following CLI commands:

ip igmp snooping

ip igmp snooping vlan 8
no ip igmp snooping vlan "for all the other vlans used on the switch but not used for igmp"

As you can see from the latest command, I have to disable the igmp for all the other Vlans. Is there a faster method?

Thanks in advance.

Best,

J

[Peter Paluch]

Hi Vincenzo,

I am afraid there is no way of doing that although I admit there should be one. The no ip igmp snooping vlan command does not accept VLAN ranges so the only way to deactivate the IGMP snooping for all but one VLAN is to explicitly deactivate it on individual VLANs, one at a time.

Then again, the IGMP snooping feature is usually a feature you would want unless there is some special need to have the multicasts flooded just like broadcasts in a particular VLAN. Are you certain you need that?

Best regards,

Peter

[Vincenzo Santoro]

Hi Peter,

Thanks for your reply. Yes, I really need IGMP snooping for IPTV....

Anyway, I'm really surprised by the fact that you need to disable the igmp snooping on all the other vlans fo which you don't need igmp snooping....it would have been much easier to enable the igmp snooping directly on a single vlan without being obliged to enable global snooping.

The same happens if you want to apply igmp snooping querier...you need to disable the snooping querier feature for all the other vlans...

Thanks again.

Best,

Vincenzo

[Peter Paluch]

Hi Vincenzo,

Actually, I was asking whether you need to deactivate the IGPM Snooping in any of your VLANs. Usually, for properly implemented IP Multicast, the IGMP Snooping is of significant help, and it does not make sense to deactivate it. Do you have any special need to deactivate the IGMP Snooping on remaining VLANs?

Anyway, this surely would be a good enhancement request - to allow using the VLAN ranges in the IGMP Snooping configuration.

Best regards,

Peter

[Vincenzo Santoro]

I'm going to use multicast traffic only on a specific VLAN, with the core switch acting as a snooping querier. So, first of all, I want to disable on the core switch the snooping querier feature on all the other VLANs in order to avoid multicast traffic not needed from the querier to the other switches.

Moreover, for security reason, I'd like to disable also the igmp snooping for all the other vlans on all the switches.