PIM Sparse mode not working when static route pointed to HSRP ip address

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Jun 13th, 2010
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Hi :

I am facing a well known issue is that when a LAN firewall points to the HSRP standby IP to reach the MCAST source and RP addresses, the IGMP Join Messages from the LAN users are not reaching the gateway routers configured with sparse mode on the LAN interfaces. *,G entries are also not forming when the F/W points to the HSRP IP address of the G/W routers. The reason is well known as the PIM neighbor messages are never sourced from a HSRP standby IP. SO when I point the frewall to the real ip of any of the routers *,G & S,G are all forming fine and the MCAST tree is building up.

Is there any workaround to this if i have to use both the gateway routers for MCAST traffic from a resiliency perspective..



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belovell Mon, 06/14/2010 - 08:39
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HSRP,VRRP, etc IP addresses cannot work with mcast for reasons even beyond what you described.This is an absolute statement, they cannot be used.

Redundacy should be handled by running PIM and a routing protocol between all L3 mcast devices and then when a link/route goes down the RIB will change and PIM will change it's RPF interface and move the flow to the new path indicated by the routing table.



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