Subject: [pim] Reg - I Need some clarification regarding PIM RPF vector implementation

From: Sundara Moorthy M <[email-masked]>
Date: Mon, 13 Jun 2011 18:55:32 +0530

Hi,

In RFC5496 (PIM RPF Vector), they have discussed with a scenario as shown below.

 ------------------ BGP ------------------------------
|                                                     |
[S]---( Edge 1)--(Core 1)---( Core )--(Core 2)---( Edge 2 )---[R]

                       <--- (S,G) Join

In this case, it is discussed that (S,G) join from Edge2  to Edge1.

Point1 :
---------------
They haven't discussed about (S,G) join from any core router.
My doubt is that if suppose the RP/Last Hop Router is the core router (consider Core2) in the above figure.

What will be vector attribute to be added in PIM JOIN format in this scenario??
Because the Vector Attribute to be added in PIM JOIN packet is the IP address of EDGE router.
But the core router doesn't know about the destination(S) and also the EDGE router to reach that destination(S).

May I know that if there is any rule that RP should be one of the edge routers ??
If not, how should we solve the above mentioned problem?

Point 2:
-------------------
What should the core router do with the received RPF vector if its neighbor is not capable of handling the RPF vector.??
Should it send JOIN with RPF vector or not??

Thanks and Regards,
 Sundara Moorthy M

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