RE: Server to Server Basic Multicast Query

The best way is just to turn IGMP Snooping on and the switches will automatically find the optimal forwarding path for the multicast within the VLAN. With Catalyst, multicast within a VLAN "just works". IGMP Snooping is only needed to optimize which ports the traffic is forwarded to. In the case of Nexus, layer 2 multicast won't work unless you have an IGMP Querier, since forwarding is done at layer 3 instead of layer 2, even for multicast that isn't routed. In NX-OS you can configure an IGMP Querier either by enabling PIM on the SVI or enabling a bogus IGMP Snooping Querier (http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/IGMPSnooping.html#wp1071684).

In your case just turning on IGMP Snooping on all devices should work. I've seen cases for Catalyst before where it "should" work, but doesn't unless you enable multicast routing though. Either way you still want IGMP Snooping so your multicast isn't treated like broadcast.

HTH,

Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13
bmcgahan_at_INE.com

Internetwork Expert, Inc.
http://www.INE.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Muhammad Anser Khan
Sent: Sunday, January 05, 2014 5:34 AM
To: Cisco Group
Subject: Server to Server Basic Multicast Query

Dear All,

I have a below query related to Basic (Server to Server) multicast within the same subnet and vlan but connected to two different switches.

Below is the scenario:

In N5K = Acting as a layer 2 and "ip igmp snooping" is enabled In Dist_CAT65K= Acting as a layer 2 for Vlan1 and "no ip igmp snooping"
configured globally (disabled)
In Core_CAT65K= Acting as a layer 3 for Vlan1 (SVI) and "no ip igmp snooping" configured globally (disabled)

Server-1 ---> N5K-1 ---> Dist_CAT65K-1 ---> "Core_CAT65K-1 <<====>> Core_CAT65K-2" <--- Dist_CAT65K-2 <---- N5K-2 <----- Server-2

Kindly suggest what is the best way to enable multicast end to end.

I have one solution to enable 'pim' under SVI in the core switch:

Core_CAT65K:
!
interface Vlan1
 ip address 1.1.1.1 255.255.255.0
 ip pim sparse-dense-mode
end
!

To enable 'pim,' Do we need to enable "ip multicast-rouing"?

Do we need to enable "ip igmp snooping" in Core_CAT65K?

Is it better to enable "ip igmp snooping" in Dist_CAT65K?

Or Multicast will still work without doing anything because IGMP is disabled on Core_CAT65K & Dist_CAT65K and Multicast packets will be treated as Broadcast in Core_CAT65K.

What is the best way?

Thanks

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Received on Sun Jan 05 2014 - 11:31:50 ART