Subject: all data packets send to their RP?

From: Hitoshi Asaeda <[email-masked]>
Date: Fri, 19 Mar 1999 02:53:48 +0900 (JST)

Hi.

If bidir PIM router sends multicast data packets to his upstream
bidir PIM router who doesn't have (*,G), all of these packets must be
forwarded toward RP.

   S--A--B--C--D--E--F--G--RP

A to G are bidir capable PIM routers and there are no receiver yet.
In this situation, S sends every multicast data packet toward RP
natively.
This means these packet are flooded from A to G, even if there
are no members and no (*,G) state?

Legacy PIM provides a method for RP not to receive unneeded data
packets with register-stop. But bidir PIM cannot prohibit to forward
all of them.

This state is unwilling, isn't it?

Regards.
--
Hitoshi Asaeda, ITS/IBM-Japan

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From: Dino Farinacci <[email-masked]>
Date: Fri, 19 Mar 1999 00:46:40 -0800 (PST)

>> are no members and no (*,G) state?

    Yes, this is correct. There is no way routers downstream from the RP
    can know if there are members upstream unless they keep (S,G) state.

    We had considered a way to send "on-demand" Prunes but that would 
    complicate the design. We also thought it wasn't worth the bang for the
    buck.

>> packets with register-stop. But bidir PIM cannot prohibit to forward

    Right.

>> This state is unwilling, isn't it?

    I think it is. Others want to comment?

Dino

---

From: Dave Thaler <[email-masked]>
Date: Fri, 19 Mar 1999 15:39:54 -0800 (PST)

>     complicate the design. We also thought it wasn't worth the bang for the

Just for comparison, this is the same as in the design of BGMP.

Draft-00 of BGMP included rules for pruning back down so the root
wouldn't get data if there were no members, but this was ripped out
in drafts -01 and higher to simplify the design.

-Dave