Subject: RE: PIM-SM join/prune suppression timer question

From: Ravi Shekhar <[email-masked]>
Date: Mon, 19 Jul 1999 17:06:29 -0400

> | In the case I was trying to describe, if its an <S, G>SPT entry,
> | - <S, G> join is sent towards S
> | - <*, G> join will be sent towards RP and an 
> |   <S, G> prune is also sent towards RP. 
> | 
> | My understanding is that <*, G>join suppression will happen 
> based on 
> | suppression timer present in <*, G> route entry and <S, 
> G>join suppression
> | will
> | happen based on suppression timer in <S, G> route entry.
> | 
> | But <S, G>prune should not be suppressed because of either 
> of these two.
> | Text in the rfc specifies "While the timer is running, 
> Join/Prune messages 
> | for the entry are not sent" which gives an impression that 
> even <S, G>prunes
> | 
> | get suppressed.
> | 
> | It looks to me that either we need another suppression 
> timer in <S,G> to 
> | suppress its prune towards RP, or it should not be 
> suppressed at all.
> 
> Join/Prune suppression timer is to avoid duplicate control 
> traffic on the
> LAN. If the <S, G> RPT entry has two different IIF's for the 
> source and
> the RP, then 
> - the RPF router towards the S would trigger the message immediately.
> - the RPF router towards the RP would trigger the message immediately.
> 
> Join/Prune suppression timer is only invoked if the received 
> join/prune message
> matches the IIF of the <*, *, RP> or <*, G> or <S, G> entry.

 In the example which I tried to explain above, its an <S, G>SPT (not RPT) 
 and the prunes towards RP are sent periodically (not triggered).

 - Ravi Shekhar.