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New Member

IGMP snooping config

Hi all,

i need to hepl with config of igmp snooping.

I have one source like DCM this DCM is connectd to Catalyst 2960S, This catalist o connected to other 2960s, this 2960s is connected with another 2960s.  A have connected from One to other witch 11 pcs of 2960S switches.

On source i Have 10 Multicast addresses 239.0.0.1 to 239.0.0.10

IGMP is traveling in VLAN40.

Can anyone helps me how to configure igmp querier ip addresses. Must i use it?

Whole network is transparent. And i Want to use IGMP filters on trunk interfaces  becouse i want to have just 2 multicast groups on last switch.

Thanx for all for help!

Thank you!

BR

Dave

Everyone's tags (2)
4 REPLIES
Cisco Employee

IGMP snooping config

Hi David,

Can anyone helps me how to configure igmp querier ip addresses. Must i use it?

An IGMP Querier must have an IP address. IGMP queries are IP packets that must have a non-zero source IP address. If the switch performing IGMP Querier function does not have an IP address, it can not send the queries. Note that IGMP reports are sent to the multicast address of the group into which the station subscribes (this is by design). Therefore, the source address of IGMP queries sent into a VLAN does not need to be from the IP address space used in that VLAN.

It is irrelevant which switch performs the IGMP Querier function as long as it sends queries into the VLAN where the recipients are located. If it is VLAN 40 then ideally, it should be the switch that has interface Vlan40 created and configured with an IP address. Otherwise, just start the IGMP Querier on any switch that has at least one IP address configured on any interface. You can read more about the way IGMP Querier selects the source IP address here:

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/15.0_2_se/configuration/guide/swigmp.html#wp1193337

And i Want to use IGMP filters on trunk interfaces  becouse i want to have just 2 multicast groups on last switch.

Are you familiar with configuring them?

Best regards,

Peter

New Member

IGMP snooping config

Thanx Peter,

yes it works. But when i tryed to apply igmp filter in more trunk interfacec and access interfaces it it now worging on all. On downlink access it works, but on downlink trunk it not working.

Have you any idea?

BR

david

Cisco Employee

IGMP snooping config

Hi David,

I apologize for responding so late. Is this issue still relevant?

Regarding the ip igmp filter configuration, this feature limits incoming IGMP Membership Reports and Leaves. As such, it is best placed on the access ports towards end stations (subscribers). I would not personally recommend using it on trunks (i.e. connections between switches) as the behavior won't be the same: the individual subscriber ports in this case are not prevented from subscribing into multicast groups so if any directly stations on the switch starts sending multicasts, other stations may see it. With individual per-access-port configuration of the IGMP filtering, this problem would be prevented.

Best regards,

Peter

New Member

IGMP snooping config

Hi peter,

my problem is that i have 800Mb/s IGMP trafic on Trunk betwen switches. Of course if i set the filter on accens interface, the filter works. But I have still all traffig on trunk = backbone. I need to select which igmp groups are aloved on trunk interface becouse i have in some cases limited capacity for eg 500 Mb/s. From this reason i need to set which IGMP groups are alloved on trunk interface.

Thank you

BR

Dave

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