Subject: [Softwires] 4rd-00 now available

From: Rémi Després <[email-masked]>
Date: Tue, 22 May 2012 09:58:41 +0200

Hello, all,

The solution that, with Reinaldo Penno, Yiu Lee, Gang Chen, and Sheng Jiang, we submit to the WG, as proposed standard for stateless IPv4 via IPv6, is now available.

The acronym is now just 4rd as other proposals using it have all expired (4rd-E and 4rd T).

As done for 6rd [RFC5969], the complete specification is in a single document, including DHCPv6 formats.
Ref: www.ietf.org/internet-drafts/draft-ietf-softwire-4rd-00.txt 

Since IETF 83, one significant point of substance has evolved: instead of being systematic, including an IPv6 fragment header is now avoided when possible without sacrificing IPv4 transparency. 
For this, TTL preservation across 4rd tunnels is now limited to TTL = 1 or 255, values that may be used to test router adjacency.

We believe this evolution is important because:
- As discussed in Paris, some IPv6 networks may treat IPv6 packets more efficiently if they have no fragment headers, at least in TCP and UDP.
- The added complexity to better deal with this is very limited.

Any questions, and remarks on the draft are most welcome.

We look forward to knowing the review-team composition when available.

Regards,
RD