Subject: Re: wg last call on: draft-ietf-mpls-in-ip-or-gre-02.txt - update

From: "W. Mark Townsley" <[email-masked]>
Date: Wed, 03 Sep 2003 18:31:21 +0200

Hi Andy,

> I'm curious what additional functionality MPLS in L2TPv3 would get you that
> GRE or direct IP encapsulation doesn't already provide.

The same two points given in the applicability statement of 
draft-ietf-mpls-in-ip-or-gre-02.txt for MPLS-in-GRE vs. MPLS-in-IP hold for 
MPLS-in-L2TPv3 vs. MPLS-in-IP. L2TPv3 also provides a method for thwarting a 
blind packet insertion attack (in the absence of IPsec) via the Cookie in the 
L2TPv3 header.

- Mark

>
> At 8/29/2003 10:26 AM -0700, David Meyer wrote:
>> One thing that would appear to be useful is to generalize the
>> draft just a bit to  mpls-in-ip-encapsulation and include L2TPv3.
>>
>> Dave

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From: Yakov Rekhter <[email-masked]>
Date: Mon, 08 Sep 2003 05:46:13 -0700

Mark,

> blind packet insertion attack (in the absence of IPsec) via the Cookie in the

The purpose of draft-ietf-mpls-in-ip-or-gre-02.txt is to define how
to run MPLS over (a) IP, and (b) over GRE. That is it.

It is *not* the purpose of the draft to define how to run MPLS over
all possible sorts of tunneling technologies (with L2TPv3 being
just *one* of such tunneling technologies).

Yakov.

P.S. One way to support MPLS over L2TPv3 is to use GRE as an
alternative encapsulation in L2TPv3.

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From: "W. Mark Townsley" <[email-masked]>
Date: Tue, 09 Sep 2003 16:45:42 +0200

> just *one* of such tunneling technologies).

Yakov,

The purpose of my email was simply to answer a direct question from Andy.

However, more to your point, as long as the GRE or IP draft is not shutting
the door to L2TPv3, I personally don't mind it being defined in a separate
document.

- Mark