Subject: draft-rosen-vpn-mcast-04.txt

From: [email-masked]
Date: Mon, 16 Sep 2002 16:11:46 +0200

A couple of questions regarding section 2 of the above mentioned draft:

1. Is there a one-to-one relation between a Multicast Domain, a VPN and
the P-group address?

2. Why is the encapsulation of the C-packet into an IP header with as
destination the P-group address and as source the ingress PE address not
a sufficient solution (for shared trees: C-packet into PIM-register into
IP unicast to RP)?  Why are MPLS & GRE encapsulations needed?

3. Regarding RPF determination: is this part still up to date (Cisco
white paper mentions a check in which the bgp next-hop address for the
source address in the C-packet is compared to the source address of the
P-packet)?

dirk

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From: "Arjen Boers" <[email-masked]>
Date: Thu, 26 Sep 2002 18:27:59 +0200

Hi Dirk,

> 1. Is there a one-to-one relation between a Multicast Domain, a VPN and

Yes, the group address defines which VRFs belong to the same Multicast
Domain
 making up the M-VPN.

> a sufficient solution

If you mean IP-in-IP encapsulation, then yes, this is theoratically
also a sufficient solution. Vendors may choose another encapsulation
if they have hardware supporting it.

>(for shared trees: C-packet into PIM-register into

I don't understand what you mean here. If registers inside the VPN are
sent to an RP which is at another site, then these packets will
be forwarded using MPLS encapsulation in the core as registers
are unicast packets

> source address in the C-packet is compared to the source address of the

The section in the draft is correct and up to date.

Cheers,
Arjen.