Re: [v4tov6transition] [Softwires] ISP support of Native IPv6 across NAT44 CPEs - Proposed 6a44 Specification

Brian E Carpenter <> Wed, 06 October 2010 22:09 UTC

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Date: Thu, 07 Oct 2010 11:10:27 +1300
From: Brian E Carpenter <>
Organization: University of Auckland
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To: Ole Troan <>
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Subject: Re: [v4tov6transition] [Softwires] ISP support of Native IPv6 across NAT44 CPEs - Proposed 6a44 Specification
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On 2010-10-06 19:57, Ole Troan wrote:
> Brian,
>>> Draft-despres-softwire-6a44-00, coauthored with Brian and Sheng, has just been posted (
>>> It describes a solution for ISPs to offer native IPv6 across IPv4-only CPEs (NAT44 CPEs).
>>> It results from convergence discussion between authors of draft-carpenter-6man-sample-00 and draft-despres-softwire-6rdplus-00, taking into account comments made by authors of draft-lee-softwire-6rd-udp-01, and those made other Softwire WG participants since IETF 78.
>>> It is submitted to become, after discussion in the WG, a Softwire I-D.
>> By the way, we do discuss in the draft why it's a useful alternative to
>> both tunnel brokers (such as Hexago and SixXs) or Teredo. We don't
>> explicitly discuss why we think it's also a useful alternative to an L2TP
>> solution, but the arguments are, I think, similar to those for the tunnel
>> brokers (apart from our "hobbyist" comment).
> perhaps you could also add some deployment considerations with regards to host tunneling versus "network" tunneling?

OK, if there is enough interest to continue this work. Of course, in the
context of legacy CPE, there is no alternative to host tunnels.
(Except for the idea in draft-lee-softwire-6rd-udp of a tiny
relay plugged into the customer LAN.)