On Sun, 14 Feb 2010, Robin Whittle wrote:

                 His proposal is intended to let a NAT box serve
                 more hosts from a single IPv4 address, by way
                 of providing new versions of TCP and UDP (SCTP?)
                 with 32 bit port numbers.

                 Paul states that his proposal would be the basis
                 for a CEE routing scaling solution, but no CEE
                 architecture works with IPv4 - and none work with
                 hosts behind NAT.

I don't think that's a fair characterisation at all of what I was suggesting. Indeed, it's completely at odds with what I was suggesting in the blog entry (I may have started with speculating about transport protocol level hacks, but that's not where my reasoning ended up). Also, it seems you're using NAT like "NAT, as NAT is today" - rather than "NAT, in the general 'rewrite' sense" or "NAT, but 2-way", which is how it ends up in what I was considering.

The suggestion is, in a nutshell:

1. Deploy an IP option that effectively adds a secondary ID space to
   the packet

Step 1 can happen because ISPs and consumers will perceive a growing problem, due to pressures on port space with NAT (NAT being the only thing people really care about in the short-term, being the assumption). Presume about 5 years to get this deployed and iron out whatever problems with core routers (i.e. pretty much same problem facing IPv6..).

2. Someone recognises that with a new address family you could allow
   2-way connectivity between these secondary ID spaces.

3. Someone takes approaches from LISP and Shim protocols and adds
   protocols to make the seconday<->middle-box mapping dynamic.

It /starts/ with solving a problem /for/ NAT. It ends up with a system that implements a "locator scope change" boundary between the core internet and a peripheral address space.

Further, I don't claim this is a well-specified system or a good one.

I'm trying to illustrate what could happen if none of the well-engineered proposals from the IETF, IRTF, etc end up being adopted, and trying to think what could happen if people instead go for 'cheap hacks' that don't particularly try to generally fix routing on the internet..

What I'm saying is that even the cheap hacks (even ones to make something as yucky as NAT work better) could potentially form a basis for something that could, in time (a long time perhaps), evolve in to a "fix routing on the internet" system.

Take it as you will.

Paul Jakma      p...@jakma.org  Key ID: 64A2FF6A
Harrisberger's Fourth Law of the Lab:
        Experience is directly proportional to the amount of equipment ruined.
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