Interim Policy proposal for IPv6 Address Assignment Policy for Internet Exchange Points

On Fri, 31 Aug 2001, Fearghas McKay wrote:
> Please send any comments to the LIR-WG list <lir-wg at ripe.net>
>
> 5. Other Considerations
> -----------------------
>
> It should be noted that ISPs usually do not announce address space
> used on the IXP mesh itself to their peers. That means the address
> space assigned under this policy is likely not to be routable
> globally.

Care to explain how traceroute through these IX's is supposed to work, if
the node performing traceroute, ping, or whatever, is not a small-scale
customer (ie. default route) of the IX participants?

As far as I can see, this is impossible.  Moreover, as the scope of these
addresses is global, the routers responding to ping, traceroute etc.
cannot select a better source address (e.g. a truly global address
assigned to loopback device) for the response packets.

The only way to deal with this, as far as I can see, is just assign like
/35's or equivalent to IX's too (it's not like there are thousands of
them!), or make the assignments from a special block which MUST be
exempted from BGP DFZ aggregation filtering rules.

Or, you could define this allocation policy only for a specific kind of
exchange points (client organizations of the IX participants must not
participate in DFZ so that there wouldn't be aggregation filtering;
often this could mean only bi-lateral peering of "small-scale" DFZ, or
smaller, organizations).  Practically, I suppose, this excludes IX's where
there are upstream/long-haul (e.g. trans-atlantic) operators present.

Practically, the address assignment seems equivalent of adding no-export
BGP community to some /35 prefix, using it for point-to-point links and
announcing it everywhere.  With some IX configurations, the results might
not be pretty for tracerouters.

I guess the easiest approach here might be to clarify (e.g. by giving
examples) which kind of IX's should/should not adopt this approach based
on the routability arguments.

(if this is not done, the IX's that can't adopt this approach might be
given cold treatment when they apply for another kind of addresses, and be
pointed out that there is already a scheme for IX's)

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords