Subject: Re: RP on a stick problem

From: Isidor Kouvelas <[email-masked]>
Date: Thu, 31 Aug 2000 17:41:44 -0700

"karim Zamani" writes:
>Hi,
>
>I run through some CISCO documents about the particular case of "RP on a
>stick". CISCO proposes solutions to this problem (atomic joins etc).
>Is there any plans to incorporate that into PIM-SM spec?
>
>Should PIM-SM implementations take that into consideration?

The new PIM spec already considers the RP-on-a-stick turnaround router
case.  On the turnaround router, in steady state the immediate (S,G)
olist is NULL but the inherited (S,G) olist is non NULL.
JoinDesired(S,G) becomes TRUE on the turnaround router when the RP
first joines towards the source (although in steady state the RP no
longer joines).
Data packets arriving on the (S,G) RPF interface of the turnaround
router update the KAT which in combination with the inherited (S,G)
olist being non-null keep JoinDesired(S,G) being true.
Hence the turnaround router keeps joining towards the source.  This
pulls the traffic on the turnaround LAN.

thanks
Isidor