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Re: using IRR tools for BGP route filtering
From: John Fraizer <nanog () EnterZone Net>
Date: Thu, 22 Jun 2000 16:05:54 -0400 (EDT)

I agree totally with prefix-list filtering customers and we have done so
from the very beginning.  (Who wants to blemish the reputation of their
ASN as result of a customer being a bonehead and announcing default, etc?)
Provider<->Provider prefix-list filtering becomes much more involved
however.  When a provider has 400+ bilateral peering relationships, the
time it takes to bring a new customer online who has their own address
space grows substantially.  It is no different when a provider obtains
additional address space.  If their peers are prefix-list filtering, they
have to contact every peer to have them blast a hole in the filters for
the new address block.

In a perfect world, we would not need to filter, period.  Filtering
customers has become necessary to survival.  I see Provider<->Provider
filtering as a major hurdle to jump anytime your (or anyone elses) network
expands in relation to prefixes being legitimately announced.

John Fraizer
EnterZone, Inc

On Thu, 22 Jun 2000, Danny McPherson wrote:

I agree with this, and have seen the document, and have worked for 
large providers that performed prefix filtering on customers long
before IOPS existed.  

However, if every ISP performed prefix-based filtering between one 
another, it'd be improved "a lot more".  I recall more than a few 
instances when providers inadvertently broke other providers customers 
by "mis-advertising" prefixes.  

And if every ISP performed SA verification between one another 
(presumably with the same filters) it would again be improved "a 
lot" more.


If every ISP does prefix based filtering on its
downstream customers, the integrity of the Internet
routing system will be improved a lot. The document
below proposes such a model:


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