Re: Shim6, was: Re: filtering /48 is going to be necessary

[Iljitsch van Beijnum <iljitsch () muada com>]

On 12 Mar 2012, at 16:21 , Leigh Porter wrote:

> > Grass-roots, bottom-up policy process
> > +
> > Need for multihoming
> > +
> > Got tired of waiting
> > =
> > IPv6 PI

> A perfect summation.

Except that it didn't happen in that order. When ARIN approved PI the shim6 effort was well underway, but it was too 
early to be able to know to what degree it would solve the multihoming problem. Earlier, when multi6 was stuck or 
later, when shim6, at least as a specification, but preferably as multiple implementations, could have been evaluated 
would both have been reasonable times to decide to go for PI instead.

Of course as has been the case over and over the argument "if you give us feature X we'll implement IPv6" has never 
borne out.

> Also given that people understand what PI space is and how it works and indeed it does pretty much just work for the 
> end users of the space.

The trouble is that it doesn't scale. Which is fine right now at the current IPv6 routing table size, but who knows 
what the next decades bring. We've been living with IPv4 for 30 years now, and IPv6 doesn't have a built-in 32-bit 
expiry date so it's almost certainly going to be around for much longer.