Re: Customer AS

[randy () psg com (Randy Bush)]

> 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
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