On Mon, Jan 22, 2024 at 11:23 AM, Bob Hinden <bob.hin...@gmail.com> wrote:
> Warren, > Just to confirm, this is: > > https://datatracker.ietf.org/doc/draft-chroboczek-int-v4-via-v6/ > > currently at -02. Correct? > Nope - this is https://datatracker.ietf.org/doc/draft-chroboczek-intarea-v4-via-v6/ (note "intarea" vs "int"). I was not paying attention when I initially named/submitted the document, and so it ended up with the wrong name, meaning that it didn't show up in the IntArea list, etc. We renamed it to https://datatracker.ietf.org/doc/draft-chroboczek-intarea-v4-via-v6/ . I have just updated the older, incorrectly named one to be a tombstone, hopefully cutting down on future confusion. Of course, this means that the older document is now at -03, and this newer, better one is at -00…. "There are only two hard problems in computer science: Cache invalidation, naming things, and off-by-one errors." — Jeff Atwood(?) W > I think this is a good idea and support it. I will try to review it and > provide more comments. The ICMP behavior is an interesting problem. > > Bob > > > > On Jan 22, 2024, at 6:39 AM, Warren Kumari <war...@kumari.net> wrote: > > Hi there all, > > I discovered that I'd somehow misnamed a draft that Juliusz Chroboczek , > Toke Høiland-Jørgensen, and myself had written — somehow I'd managed to > name it draft-chroboczek-int-v4-via-v6, instead > of draft-chroboczek-intarea-v4-via-v6. > > Anyway, it is targeted at intarea, and so I renamed and submitted it, so > that it will now actually show up in the IntArea list of documents… > > The document proposes "v4-via-v6" routing, a technique that uses IPv6 > next-hop addresses for routing IPv4 packets, thus making it possible to > route IPv4 packets across a network where routers have not been assigned > IPv4 addresses. > > This isn't yet another "let's rewrite part of the header and override some > bits", nor some new protocol / tunneling thing. It simply notes that > routers only need to determine the outgoing interface (and usually MAC > address) for a packet, and so it's perfectly acceptable for the next-hop > for e.g 192.0.2.0/24 to be e.g 2001:db8::2342. The router don't care… > > While this may be initially surprising to many people, it's actually > nothing "special", nor really groundbreaking - it's just how IP routing > works. However, because it is surprising, it is not getting widely used — > and that means that many interfaces need IPv4 addresses where they > otherwise would not. > > In fact, this functionality is already supported in (at least!): > Arista EOS (since EOS-4.30.1) > The Babel protocol > Linux (since kernel version 5.2) > Mikrotik RouterOS (since before 7.11beta2) > and the BGP protocol (see RFC8950 - "Advertising IPv4 Network Layer > Reachability Information (NLRI) with an IPv6 Next Hop"). > > So, if this already works, why are we writing a document?! > > A few reasons, including: > 1: This behavior / capability is surprising to many people - this means > that people are "forced" to use IPv4 addresses where they otherwise would > not. > > 2: There should be an easy way to reference this type of > behaviour/deployment - the genesis of this document that Babel supports > this (RFC9229 - "IPv4 Routes with an IPv6 Next Hop in the Babel Routing > Protocol" <https://datatracker.ietf.org/doc/rfc9229/>), but had to > describe the behavior because there was nothing to point at. > > 2: A large number of implementations don't currently support it (or, at > least, the tooling / CLI / UI doesn't allow configurations like the above). > > 3: There are some unsettled questions around the ICMP behavior — e.g: if a > router has to send an ICMP packet too big, and it doesn't have an IPv4 > address, what should it do? > > We'd really appreciate review and feedback — again, this isn't documenting > a major "change", but more noting this the design of command lines, > tooling, etc should allow it. > > W > > > > _______________________________________________ > Int-area mailing list > Int-area@ietf.org > https://www.ietf.org/mailman/listinfo/int-area > >
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