[3711] in North American Network Operators' Group
Re: Customer AS
daemon@ATHENA.MIT.EDU (Randy Bush)
Fri Aug 16 22:32:08 1996
Date: Fri, 16 Aug 96 19:27 PDT
From: randy@psg.com (Randy Bush)
To: Paul Ferguson <pferguso@cisco.com>
Cc: nanog@merit.edu
> Not sure what you mean here concerning 'unroutable' prefixes, but the
> issue with obtaining an allocation for one of the upstream provider's
> CIDR block when multihomed *does* have its drawbacks, at least from
> the end-user perspective. If said prefix (let's say a /24) is announced
> in the 'allocating' provider's aggregate, and the more specific is
> announced via the 'other' provider, the more specific will always be
> preferred.
This is brain damaged. Given
AS1 ----- Sprint
|
|
|
|
AS2 ----- anything else not Sprint
You can not announce a bit of Sprint space AS1->AS2->MCI as a fallback (note
the 'extra' AS hop) because Sprint aggregates your announcement and the
longer prefix is announced to the world via <anything else>.
Use Sprint space, bye bye fallback.
To the best of my knowledge (which ain't that hot), all other providers have
discovered suppress-map.
randy