Multicast with hsrp

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Jan 26th, 2009
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Here is the design

core 1 is at location A which consists 2 6509's running hsrp for roughly 20 vlans..

core 2 is at location B which consists of 2 6509's running HSRP for roughly 30 vlans.

Location A and B are connected via 1 WAN link.

With multicast running are there anything to take into consideration when implimenting multicast, that would be out of the ordinary due to HSRP. Will be using BSR with sparse mode only.

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Laurent Aubert Mon, 01/26/2009 - 18:35
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Multicast packets generated by HSRP are local scope only so you don't have to worry.



crow930us Tue, 01/27/2009 - 00:47
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When using multicast in an HSRP environment, care must be used in configuring multicast with the physical IP address as opposed to the HSRP logical address as the IP Address. If the HSRP address is used, multicast traffic will not be sent. Why Doesn't PIM Sparse Mode Work with a Static Route to an HSRP Address

mikegrous Tue, 01/27/2009 - 04:10
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Thanks. I was thinking of adding a Loopback on the switches for the RP. So it doesnt look i will have a problem. Thanks guys.

jpoplawski Wed, 07/27/2011 - 12:47
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I've just recently run into the exact same issue.  I configured an Mroute to the physical IP of one of the routers in the HSRP group and it works.  I attempt it to HSRP doesn't work.  Re-configure to the other physical IP and works fine.  Contacted TAC, they looked through my configs and said everything is configured appropriately, just not an option in my particular design.

Not sure how this works with respect to redundancy, however I'm assuming it's a manual process to fail over.  Unless someone else has found a solution I'm not aware of.

Hope this helps, the article previously mentioned is the right answer.


jpoplawski Thu, 07/28/2011 - 07:09
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  Not sure that applies here.  I have a single source from a provider.  I have two ethernet ports handed to me running HSRP.  The issue that I see is I'm not sending my request upstream to the RP as I don't have a PIM neighbor with my provider's HSRP address.  Literally the provider is on one VLAN, my client is on another.  3750 stack, no ACLs or anthing, pim sparse mode on both interfaces, etc.


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