Re: [v6ops] PI [ULA draft revision #2 Regarding isolated networks]

[t.petch <[e-mail]>]

----- Original Message -----
From: "Tore Anderson" <[e-mail]>
To: "Brian E Carpenter" <[e-mail]>
Cc: "V6 Ops List" <[e-mail]>
Sent: Wednesday, May 28, 2014 11:09 PM

> * Brian E Carpenter
>
> > Tore,
> >
> >> We have a few customers in the same situation. So we obtained a PI
> >> prefix for them,
> >
> > The important words there are "a few". As long as the numbers are
> > reasonable, this scales. When the numbers cease to be reasonable,
> > it doesn't scale. The estimate I made some years ago, based on
> > a little research into statistics in a few countries, was that
> > there must be about 10 million small or medium enterprises in the
> > world. We don't know how to route 10M prefixes in BGP-4. So
> > somewhere between "PI for a few customers" and "PI for every
> > enterprise", we have to stop.
>
> For sure, it is a very small minority of my customers who have this
> requirement. The vast majority are perfectly happy to be assigned
> prefixes out of my PA block. This goes for IPv4 too, BTW.
>
> I seriously doubt that a significant fraction of those 10M enterprises
> asking for a PI prefix (or multihoming at all) is a realistic
scenario.
> So I'm not too worried about IPv6 PI to be honest, we survived IPv4 PI
> so far and I think we'll survive IPv6 PI also, even if adding a few
> "new" PI holders who in IPv4 multihomed using PA assignments from
their
> upstreams + NAT44 + RFC1918. Especially if homenet comes up with an
even
> more attractive solution than PI for that specific use case soon.

Tore

The damage done by PI in IPv4 was understood before the RIRs  started
handing out addresses in large numbers, so while PI exists, it has
always been hard to get.

The fear with IPv6 is that just because one constraint on PI has been
removed, those handing out addresses will not realise that there is
another show-stopping constraint in the number of entries a FIB can cope
with, 1M being the best estimate (as before, on the RRG list) with the
foreseeable improvements to current technology.

And I think that every SME who has lost business with the unreliability
of their ISP will want multi-homing and will think that with IPv6 and PI
the constraints have gone, and the number of such SMEs can only approach
10M over time.

So, Brian is spot on, and just as the IETF did little about IPv4
addresses running out until the event loomed large, so I expect history
to repeat itself with the growth of PI in IPv6.

Tom Petch
>
> Tore
>
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