Re: IPv6 fc00::/7 — Unique local addresses

[Owen DeLong <owen () delong com>]

On Oct 21, 2010, at 3:15 PM, Mark Andrews wrote:

> In message <E22A56B3-68F1-4A75-A091-E416800C485B () delong com>, Owen DeLong write
> s:
> > > > >
> > > > Which is part one of the three things that have to happen to make ULA
> > > > really bad for the internet.
> > > >
> > > > Part 2 will be when the first provider accepts a large sum of money to
> > > > route it within their public network between multiple sites owned by
> > > > the same customer.
> > >
> > > That same customer is also going to have enough global address
> > > space to be able to reach other global destinations, at least enough
> > > space for all nodes that are permitted to access the Internet, if not
> > > more. Proper global address space ensures that if a global destination
> > > is reachable, then there is a high probability of successfully reaching
> > > it. The scope of external ULA reachability, regardless of how much
> > > money is thrown at the problem, isn't going to be as good as proper
> > > global addresses.
> > _IF_ they implement as intended and as documented. As you've
> > noted there's a lot of confusion and a lot of people not reading the
> > documents, latching onto ULA and deciding ti's good.
> >
> > It's not a big leap for some company to do a huge ULA deployment
> > saying "this will never connect to the intarweb thingy" and 5-10 years
> > later not want to redeploy all their addressing, so, they start throwing
> > money at getting providers to do what they shouldn't instead of
> > readdressing their networks.
>
> IPv4 think.
>
> You don't re-address you add a new address to every node.  IPv6 is
> designed for multiple addresses.
That's a form of re-addressing. It's not removing the old addresses, but,
it is a major undertaking just the same in a large deployment.

> > > For private site interconnect, I'd think it more likely that the
> > > provider would isolate the customers traffic and ULA address space via
> > > something like a VPN service e.g. MPLS, IPsec.
> > One would hope, but, I bet laziness and misunderstanding trumps
> > reason and adherence to RFCs over the long term. Since ULA
> > won't get hard-coded into routers as unroutable (it can't),
>
> Actually it can be.  You just need a easy switch to turn it off.  The
> router can even work itself out many times.  Configure multiple interfaces
> from the same ULA /48 and you pass traffic for the /48 between those
> interfaces.  You also pass routes for that /48 via those interfaces.
If you have an easy switch to turn it off, it will get used, thus meaning that
it isn't hard coded, it's just default.
>
Owen