Re: BBC does IPv6 ;) (Was: large multi-site enterprises and PI

[Paul Vixie <paul () vix com>]

i was waiting and watching and looking and hoping for this.  now i have it.

> From: Iljitsch van Beijnum <iljitsch () muada com>

> ... We have 128 bits, so we should make good use of them.  One way to
> do this is to make all subnets and 99% of end-user assignements the
> same size.  Yes, this wastes bits, but the bits are there anyway so not
> wasting them really doesn't buy you anything at this point.

this demonstrates the same unifying/universal error that fred was on about,
which is that some people doing resource planning making assumptions about
what the other people affected by those plans actually want or need.  and
it is the clearest statement i have yet seen of the part of Iljitsch's 
thinking that i flatly disagree with.

the short version of my rebuttal is: "those are not your bits to waste."

the longer version is what padlipsky said about "maps" and "territories"
(or about "descriptive" and "prescriptive" design.)

> > i life fred's reasoning.  companies with size and qualifications
> > like cisco's should qualify for an ASN and for PI space.  all the
> > world's not a home-DSL or home-cable or isp-colo network.  routing
> > shouldn't always follow addressing.  we'll need to discover a
> > workable equilibrium unless we want to encourage NAT in IPv6 the
> > same way we (passively) encouraged it in IPv4.
>
> All I hear is how this company or that enterprise "should qualify" for
> PI space.  What I don't hear is what's going to happen when the
> routing tables grow too large, or how to prevent this.  I think just
> about anyone "should qualify", but ONLY if there is some form of
> aggregation possible.  PI in IPv6 without aggregation would be a
> bigger mistake than all other IPv6 mistakes so far.

first let me include owen delong's reply to this bit, in case he's in
anybody's KILL file -- he really hit it on the head this time and
deserves to be heard:

| And v6 without PI for will not get widespread adoption.
| 
| Further, ULA will become de facto PI without aggregation.  Hence my
| believe that ULA is a bad idea, and, my recommendation that we face
| the reality that PI is an important thing (unless we want to replicate
| the v4 NAT mess).  As such, I'd much rather see us develop sane PI
| policy than continue down the present road.

second, let me add, "and it's not your routing table, either."  to
make ipv6 take off we'll either have to grind down the folks who don't
want to be locked in (and have their downstreams locked in) to a single
upstream; or we'll have to insert rapid renumbering into a design that
makes no allowance for it; or we'll have to let PI happen in ipv6 as it
has in ipv4 -- through careful equilibrium; or we'll have to let NAT
happen in ipv4 as it has in ipv6.

the delicious thing about those prescriptions is that there is no "we"
and it's not up to "us".  what will actually happen is something we can
predict before, and describe after, but not actually control.  i predict
that a bunch of ivory tower propeller heads will block everything they
think is impure and that the market will have to decide on "dual-stack
forever with NAT on both stacks."