Subject: PIM snooping in VPLS without forwarding plane change

From: Xu Xiaohu <[email-masked]>
Date: Thu, 27 Mar 2008 16:56:35 +0100

Hi all,

With the approach of PIM snooping in VPLS defined in
draft-ietf-l2vpn-vpls-pim-snooping-01.txt, the multicast packet forwarding
in VPLS should be based on the L3 information in the packets. Does this
imply a big change in current VPLS forwarding behavior?

How about establishing L2 multicast forwarding table (like PIM/IGMP snooping
in switch) by using PIM snooping? In this way, it only needs to change the
control plane but not the forwarding plane.

Any comments welcomed!

Best regards, 
Xiaohu XU

---

From: "HEMIGE Venu" <[email-masked]>
Date: Mon, 31 Mar 2008 12:47:28 -0500

Xu,

The pim-snooping draft does not require any forwarding plane changes
except what is required to allow the node examine PIM Hello and
Join/Prune packets. You could choose to do MAC-DA based forwarding if
that is what your forwarding plane supports. Only downside is that there
can be non-optimal forwarding in doing that if multiple groups or (S,G)s
map to the same MAC address.

Mapping the (S,G)s to a L2 multicast forwarding table is an node-local
behavior and I think it does not need specification in the draft. 

Regards,
-Venu

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] 
> On Behalf Of Xu Xiaohu
> Sent: Thursday, March 27, 2008 8:57 AM
> To: [email-masked]
> Subject: PIM snooping in VPLS without forwarding plane change
> 
> Hi all,
>