first hop multicast redundancy

[branfarm1]

Hi there,

I have a pair of 6500's that route multicast onto a particular vlan that is connected to both switches.   The switches are in an HSRP group and currently pim is enabled only on the primary switch, which also acts as the default gateway for the vlan.  I tried enabled pim sparse-dense-mode on the secondary switch, but found that it caused all of my multicast to stop flowing after about two mins.  I know that this corresponds with an IGMP query timeout interval and I'm wondering if the problem is related to the fact that the lower IP interface is elected Multicast DR router, but the higher interface gets the IGMP querier role.  Does that sound right?  If so, what are the recommendations for configuring multicast parameters in this type of scenario?

Regards,

Brandon

[Yogesh Ramdoss]

Hello Brandon.

In a vlan/segment, router with highest IP address should become PIM Designated Router (DR) and lowest IP address becomes IGMP querier.

IGMP Querier sends query message every 60 seconds (by default). Unless IGMP query is disabled (or removing IP address under the vlan or disabling PIM etc) the router should not stop sending querier messages.

With information provided, I am not able to say why multicast stopped working.

Yogesh