North American Network Operators Group

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Re: multi-homing fixes

  • From: Clayton Fiske
  • Date: Wed Aug 29 14:10:23 2001

On Wed, Aug 29, 2001 at 07:12:19PM +0200, Iljitsch van Beijnum wrote:
> Sorry for the late reply.
> On Fri, 24 Aug 2001, Randy Bush wrote:
> > the /24s of small multihomers is half the routing table (see geoff's data)
> This can't possibly be correct. The last figure I read was that there are
> about 70k /24s. There are about 21k AS numbers out there. This means that
> by far most of the announcements, including /24s, are the result of lack
> of CIDR. Either because ISPs have a relatively large number of PA blocks
> (address conservation) or because of lack of aggregation.

Small multihomer /24s aren't necessarily their own. I've dealt with plenty
of customers multihoming with a /24 from their other provider without
running BGP. No extra AS number, but the /24 still shows up in the global
table. Also seen customers with their own /24, but having us originate it
rather than doing BGP with them.