Re: Sprint's route filters and Europe

["Alex.Bligh" <amb () xara net>]

> It sounds like what you are saying is you will be advertising 2 /19s
> plus advertising a /18 that you won't be registering just to get the
> traffic to come out of Sprint.
>
> You can certainly register a /18 and the whole world would much rather
> you advertised just the /18 and and not the /19s.
>
> This sounds to me like some people don't know or care who the other
> /19 belongs to and are just announcing the /18 for Sprint's sake.  The
> two /19s would be announced regardless of anything ANS does or
> regardless of any registry issues.  Is this the case?

See my later mail. Of course it would be irresponsible to do this without
consent of the owner of the upper half of the /18, however most (all
that I've seen) of the /19s RIPE are currently assigning from 195
have been lower /19s with the upper half not used, so they can grow.
Please don't take what I wrote as a criticism of ANS - I've never had any
problem with ANS filtering as it's entirely predictable and worked
precisely in parallel with the registries, and the ANS NOC is admirably
helpful in sorting out any filtering problems. I was describing
a marginally unpleasant workaround to an otherwise intractable (sp?)
problem (RIPE and Sprint not agreeing on minimum block size) - and
AFAIK the only way to get /19s routed to Sprint when the other half isn't
in use in many cases (yes, I know about proxy aggregation etc.). I'd be the
first to say it isn't nice, but fortunately it's now (or will soon be)
unnecessary. My point was the fact RIPE and Sprint *didn't* agree
would actually encourage hacks like this and in some cases increase
the number of routes carried.

Alex Bligh
Xara Networks



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