Subject: Mail from softwire working group about 4rd

From: Suresh Krishnan <[email-masked]>
Date: Fri, 7 Dec 2012 19:14:11 -0500

Hi all,

The 4rd draft (http://tools.ietf.org/html/draft-ietf-softwire-4rd-04)
describes a solution for providing IPv4 connectivity over IPv6. The
draft describes the method for mapping 4rd IPv4 addresses to 4rd IPv6
Addresses. It uses a 4rd specific mark called the V octet in the first 8
bits of the Interface Identifier. There were some concerns raised in
softwire about whether such addresses are actually compatible with the
IPv6 addressing architecture. Whether this is actually compatible with
the IPv6 addressing architecture is outside the scope of the softwire
wg. Hence we would like to hear the 6man wg's perspective on this. I
would like to request the wg to please go over the NOTE in Section 4.5
page 18, which explains the issue, and over IANA Considerations Section
6, and chime in on whether this is acceptable from a 6man perspective.

Thanks
Suresh

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From: Jon Steen <[email-masked]>
Date: Fri, 7 Dec 2012 19:51:02 -0500

So who is looking at LISP?

Sent from my iPhone

On Dec 7, 2012, at 7:14 PM, Suresh Krishnan <[email-masked]> wrote:

> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [email-masked]
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------

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From: Jouni Korhonen <[email-masked]>
Date: Wed, 12 Dec 2012 11:04:27 +0200

Hi,

> Addresses. It uses a 4rd specific mark called the V octet in the first 8

V-octet was AFAIR first time discussed within the Softwire MAP design team 
and I had/expressed my concerns already that time. My argumentation was that
we cannot just redefine the u & g bit use without actually having it verified
against and reflected in RFC4291. Glad to see it happening now ;)

IMHO the current language in RFC4291 does not give enough freedom to use
u=g=1, since such combination is not specifically left unused/reserved
(although u=g=1 makes no sense for the current IPv6). IEEE allows MAC
addresses that have I/G set to 1 and U/L set to 0, which makes me rather
uncomfortable with IETF using u=g=1 for their own purposes.

- Jouni

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From: Rémi Després <[email-masked]>
Date: Wed, 12 Dec 2012 14:29:16 +0100

Hi, Jouni,

2012-12-12 10:04, Jouni Korhonen <[email-masked]> :

> (although u=g=1 makes no sense for the current IPv6).

> IEEE allows MAC

IEEE indeed permits group addresses for multiple interfaces that share a common address but, as we are in the context of IPv6 UNICAST addresses, interface all our IEEE-address derived IIDs have g=0. IETF can take advantage of this fact without risk to interfere with IEEE, 

For more details, please see my last answer to Bob.

Regards,
RD

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From: Jouni Korhonen <[email-masked]>
Date: Wed, 12 Dec 2012 18:12:20 +0200

Remi,

> IEEE indeed permits group addresses for multiple interfaces that share a common address but, as we are in the context of IPv6 UNICAST addresses, interface all our IEEE-address derived IIDs have g=0…

As I said above the u=g=1 (U/L=0, I/G=1) makes no sense to current IPv6 use (thus it looks like
it could be used for other purposes). However, my point is that now we would be stepping into IEEE territory, which I am not comfortable with.

- JOuni

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From: Rémi Després <[email-masked]>
Date: Wed, 12 Dec 2012 17:15:38 +0100

Le 2012-12-12 à 17:12, Jouni Korhonen <[email-masked]> a écrit :

> it could be used for other purposes).

OK.

> However, my point is that now we would be stepping into IEEE territory, which I am not comfortable with.

My last answer to Brian answers this concern (I think).
RD

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From: Roger Jørgensen <[email-masked]>
Date: Wed, 12 Dec 2012 17:18:31 +0100

> 6, and chime in on whether this is acceptable from a 6man perspective.

Beside all the other concern being rised that question this draft I
have a hard time finding any reason for why we need yet another
mapping system.

-- 

Roger Jorgensen           | ROJO9-RIPE
[email-masked]          | - IPv6 is The Key!
http://www.jorgensen.no   | [email-masked]

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From: Rémi Després <[email-masked]>
Date: Wed, 12 Dec 2012 17:22:22 +0100

> have a hard time finding any reason for why we need yet another

Can we limit the discussion in 6man to what concerns IPv6 address formats?
(Restarting here the lengthy Softwire discussion would be a waste of time.)

Thanks,
RD