Re: Multicas RPF check with multiple equal cost paths to the

Hi,

This is not a simple question, as it may seem at the first sight. By
default, the RPF interface is selected among multiple equal-costs
paths based on the PIM neighbor with the highest IP address (that is,
assuming PIM is in use). This behavior could be changed using IP
Multicast ECMP feature found in Cisco IOS. You may read more about
this following this link:

http://www.cisco.com/en/US/docs/ios/12_4t/ip_mcast/configuration/guide/mctlsplt.html

It will explain the basic multicast multipath feature, various
configuration options and multicast ECMP limitations. To me, it would
be interesting to someone implementing unequal-cost multicast
multipath based on Loop-Free-Alternatives or something similar. There
was a lot of work implementing IP FRR for unicast traffic so it would
seem reasonable to extended it for multicast traffic protection.

HTH,

-- 
Petr Lapukhov, petr_at_INE.com
CCIE #16379 (R&S/Security/SP/Voice)
Internetwork Expert, Inc.
http://www.INE.com
Toll Free: 877-224-8987
Outside US: 775-826-4344
2010/1/17 Jorge Cortes <jorge.cortes.cano_at_gmail.com>:
> Hi team,
>
> When a router that has multicast receivers directly attached to it has
> multiple equal cost paths (interfaces) to get to the source of
> multicast traffic, what is the criteria it uses to determine the
> interface it will use for RPF? Or will all interfaces be valid RPF
> interfaces?
>
> Regards,
>
> Jorge
>
>
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