North American Network Operators Group

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Re: Verio Peering Question

  • From: Paul Schultz
  • Date: Sat Sep 29 08:36:22 2001

On Fri, 28 Sep 2001, Jeff Mcadams wrote:

> Since the length of the prefix bears little correlation to the
> "importance" of the network being advertised, there is little reason to
> filter based on the length of the prefix.

In addition to that, the prefix filtering mechanisms that are being
discussed don't apply at all to providers who are allocated much larger
blocks (/16+) yet feel the need to slice and dice it into individual /20's
to steer traffic.

Can someone who is in favor of implementing filters explain to me why
slicing a /16 into 16 /20's is any different than slicing a /20 into 16
/24's?  If the thought is "you're given a /20, i only want to see a
/20.." then why doesn't "you're given a /18, I only want to see a
/18" also apply?

I don't have any hard evidence to know how much of an impact this
actually has, but I would be very interested to see how many more specific
/19's and /20's exist in a "verio-filtered" table that were allocated as
/16's and shorter.