nanog mailing list archives
Re: A straightforward transition plan (was: Re: V6 still not supported)
From: Mark Andrews <marka () isc org>
Date: Thu, 31 Mar 2022 10:32:01 +1100
On 26 Mar 2022, at 21:51, Philip Homburg <pch-nanog-2 () u-1 phicoh com> wrote:If there is a magical transition technology that allows an IPv6-only host totalk to an IPv4-only host, then let's deploy it.DNS64/NAT64, DS-Lite, 6rd, 464XLAT, MAP-T, MAP-E, ? pick a transition protocol and see what happens! (with more coming every year...)The problem with these is that they are not full solutions. That's why we get new ones every year: everybody picks the subset of the problem they want solve. To go over the ones you listed: - 6rd. That's the odd one out here. 6rd privdes IPv6 over an IPv4 infrastructure. Very useful when there was not a lot of IPv6 native. Not a good approach for organisations that lack IPv4 addresses. Also not a good approach if you want to switch off IPv4 at some point. - DS-Lite, MAP-T, MAP-E. Good for connecting CPEs to IPv4aaS over an IPv6-only backbone. Downstream from the CPE is dual stack. For this reason those protocols do not see much use outside ISP networks. Got a great transition technology because hosts will keep IPv4 until the last IPv4 on the internet is gone. It is a bit of an IETF failure that we have so many ways to connect a CPE to IPv4aaS. - NAT64/DNS64. This is the closest to an actual transition technology. Unfortunately it is completely flawed in too many ways. - 464XLAT fixes many issues with NAT64/DNS64. The downside is again that hosts have to have an IPv4 stack until forever and in addition to that a complex IPv4-to-IPv6 translation module. That fails the requirement that an IPv6 stack should have roughly the same complexity as IPv4 and talk to IPv4-only. Basically, there is no solution to the transition problem. There are lots of partial solutions, each with their own advantages and disadvantages. If we could go back in time, then developing NAT64 along with IPv6 and making sure the translation really works including edge cases like IPv4 literals, DNS A records, NAT traversal, etc. would have made a difference. I don't know if such translation gateways were considered, I can't recall much discussion about them. By the time the IPv6 socket API was created it was already too late to get things like IPv4 literals right.
DS-Lite was designed to be implemented in the node. You can run IPv6-only everywhere in your network. It is simple IPv4 in IPv6 encapsulation. There was a DHCPv6 option to tell the node how to configure the remote IPv6 tunnel end point and everything else had defaults. You could implement this in stack that only presented IPv6 to the application using IPv4 mapped address. You use getaddrinfo with AI_V4MAPPED set for domain names and address literals which should preference IPv6 over mapped IPv4 moving the traffic to IPv6. Yes, you still have a stub IPv4 implementation. All this was available before DNS64/NAT64, MAP-E, MAP-T, and 464XLAT. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka () isc org
Current thread:
- Re: V6 still not supported, (continued)
- Re: V6 still not supported Philip Homburg (Mar 28)
- Re: V6 still not supported Masataka Ohta (Mar 28)
- RE: V6 still not supported Pascal Thubert (pthubert) via NANOG (Mar 28)
- RE: V6 still not supported Ryland Kremeier (Mar 28)
- Re: V6 still not supported Owen DeLong via NANOG (Mar 30)
- Re: V6 still not supported Matthew Craig (Mar 25)
- A straightforward transition plan (was: Re: V6 still not supported) John Curran (Mar 24)
- Re: A straightforward transition plan (was: Re: V6 still not supported) Philip Homburg (Mar 28)
- Re: A straightforward transition plan (was: Re: V6 still not supported) John Curran (Mar 25)
- Re: A straightforward transition plan (was: Re: V6 still not supported) Philip Homburg (Mar 28)
- Re: A straightforward transition plan (was: Re: V6 still not supported) Mark Andrews (Mar 30)
- RE: A straightforward transition plan (was: Re: V6 still not supported) Pascal Thubert (pthubert) via NANOG (Mar 31)
- Re: A straightforward transition plan (was: Re: V6 still not supported) JORDI PALET MARTINEZ via NANOG (Mar 28)
- Re: A straightforward transition plan (was: Re: V6 still not supported) Ca By (Mar 28)
- Re: A straightforward transition plan (was: Re: V6 still not supported) Joe Maimon (Mar 28)
- Re: V6 still not supported Masataka Ohta (Mar 24)
- RE: V6 still not supported Pascal Thubert (pthubert) via NANOG (Mar 23)
- Re: V6 still not supported Re: 202203231017.AYC Abraham Y. Chen (Mar 23)
- RE: V6 still not supported Re: 202203231017.AYC Pascal Thubert (pthubert) via NANOG (Mar 23)
- Message not available
- Re: V6 still not supported R: 202203232156.AYC Abraham Y. Chen (Mar 25)
- Re: V6 still not supported Re: 202203231017.AYC Abraham Y. Chen (Mar 25)