[6bone] Exchange Point Addresses

[Robert Kiessling]

Pim van Pelt <pim@ipng.nl> writes:

> | It fulfils exactly what it's made for: to provide neutral,
> | provider-independent IPv6 addresses for the exchange mesh. There was
> | and is a need for this, so it's far from "100% useless".
>  
> Sitelocal will do fine for these things. If you can't route it, I don't
> see the point in having it allocated from the 2000::/3 aggregate. I
> would find fec0::/10 addresses in the peering mesh useful. 

Three things spring to my mind:

1. reverse DNS is not possible with site-local addresses

2. with site-local addresses on IXP LAN, a router is in two different
   local domains, with possible nasty interactions between the two 
   "site local" domains

3. missing traceroutes hops through IPX LANs with site-local addresses

> We have seen (in practice) that not having globally routable peering
> meshes, potentially breaks Path MTU discovery.

Then you see something I've never seen. RFC1918 addresses pose
problems to PMTUD, that's true, but for different reasons.

> Some router implementations drop any packets from sources which they do 
> not have a route to in their FIB.

Which implementations do this?

Even if you have such an implementation, you'd just need to nullroute
the allocation from which IXP addresses are taken.

> This would be lying to the RIR, and that type of behavior is being
> actively promoted these days, [...]

I didn't want to suggest to lie, but to honestly fulfil the criteria.

> | There is a clear consencus that this is not desirable.
> I consent to not having PI, I do not consent to having the 2001:7f8::/32
> superblock with /48 allocations for peering meshes.

What would be your suggestion then? Giving routable blocks to IXPs
which do not do end-user assignments *is* PI.

> Oh, did I mention that the RIRs themselves face exactly the same problem ? 

You mentioned it. Still I fail see why this a problem. If it was, then
is would be a problem not just for IXPs and RIPE, but for many other
organsations too. IXPs and RIPE are not special in this respect.

Robert