Subject: Re: Fwd: draft-ietf-l3vpn-mvpn-considerations-05

From: Yakov Rekhter <[email-masked]>
Date: Wed, 16 Dec 2009 07:13:08 -0800

Maria,

> Clearly, the amount of processing on the upstream PE to which the
> joined is destined is not the same as the "processing" on other PEs. Any
> other PE than the upstream PE will simply discard this Join because the
> neighbor address in the PIM Join is not this PE address. 

The last sentence above is incorrect. Specifically, some other than
the upstream PE can *not* "simply discard" the Join(C-S, C-G)/Join(C-*, C-G)
just "because the neighbor address in the Join is not this PE
address", as that other PE may wish to propagate a
Join(C-S, C-G)/Join(C-*, C-G) upstream.

>From 4.5.7 of rfc4601:

    If a router wishes to propagate a Join(S,G) upstream, it must also
    watch for messages on its upstream interface from other routers on
    that subnet, and these may modify its behavior. 

Yakov.

---

From: "NAPIERALA, MARIA H (ATTLABS)" <[email-masked]>
Date: Wed, 16 Dec 2009 11:38:45 -0500

Yakov,

as Thomas correctly stated in one the e-mails he sent today:

"the other PEs parse the message, and lookup their TIB to possibly 
find an (S,G) state; they find none and discard the information in this 
Join) ; note that they don't have any (S,G) state at this point"

This is what I meant.

Maria

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf
> Of Yakov Rekhter
> Sent: Wednesday, December 16, 2009 10:13 AM
> To: NAPIERALA, MARIA H (ATTLABS)
> Cc: Thomas Morin; [email-masked]
> Subject: Re: Fwd: draft-ietf-l3vpn-mvpn-considerations-05
> 
> Maria,
> 
> the upstream PE can *not* "simply discard" the Join(C-S,
C-G)/Join(C-*,
> C-G)