nanog mailing list archives

Re: FW: /8s and filtering


From: Harsha Narayan <hnarayan () cs ucsd edu>
Date: Tue, 10 Dec 2002 10:47:29 -0800 (PST)


Hello,
  I had the same questions. Could someone please answer these?

Harsha.

On Tue, 10 Dec 2002, Forrest wrote:




I was also curious about this - if I am a customer who wants to
multihome and can justify only a /24, I would go to an ISP which has an
allocation from the Class C space rather than one from the Class A
space.

    It doesn't matter. For all practical purposes, basement multihomers
only
care that their two or three providers have their route.


Maybe I'm missing something, but what good would it do for someone to
multihome if only their own providers accept their route, but nobody else
does?  I realize that their block should be still announced with their
ISP's larger aggregate, but what good does this do if your ISP goes down
and can't announce the large aggregate.

If you're a smaller organization, perhaps you'll only have a /23 from your
upstream provider.  With the filtering that seems to be in place, it seems
like the only way you can truly multihome with a /23 is if it happens to
be in the old Class C space.  Or is this wrong?

What seems to be needed is perhaps a /8 set aside by the RIR specifically
to allocate to small organizations that wish to multihome that people
would accept /24 and shorter from.

Forrest




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