Customer AS

Randy Bush randy at
Sat Aug 17 16:35:00 UTC 1996

Mornin' Curtis,

>>> 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.

> What are you saying is brain damaged?  The idea of announcing a dual
> homed route as part of an aggregate?  Or Sprint?

Sprint's policy.  And they are *proud* of the policy.  To quote ...

    Sprint is in the process of aggregating as much of the network as we
    can to reduce the overall number of announcements that need to be made
    and to avoid having to register each IP block with companie such as ANS
    for routing through their network.

    SprintLink NOC

Peter's RADB entries are a good giggle, as they can be generally ignored.
This policy can not be ignored.

What Sprint's policy is actually meant to do is to discourage customers
from multi-homing to other providers.  What their policy actually does is
convince wise folk not to buy from Sprint.


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