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Re: The Cidr Report

  • From: Stephen J. Wilcox
  • Date: Fri Nov 14 18:57:46 2003

On Fri, 14 Nov 2003, Suresh Ramasubramanian wrote:
> Stephen J. Wilcox writes on 11/14/2003 12:54 PM:
> 
> > Yeah maybe but what about where the RIRs have assigned independent /24 space..  
> > or ISPs have subdelegated the IPs to a multihomed customer, was more thinking
> > about where a bunch of routes originating from a single ASN can be aggregated 
> > rather than routing bloat in general. There are numerous such examples of people 
> > with eg a /19 announcing 32x /24 etc
> 
> So how do you deal with one but not with the other?

I think your confusing my point - they're different questions, legitimate
announcement of /24s by multihoming corporates is at least in principal okay.
But I do regulary see people announcing consecutive prefixes all originating in
the same AS and (from my view) having the same policy.

Ok look heres one example, looks like these guys have a /20:

Broad Band Networks / ESINET BBNESINET-48 (NET-12-5-48-0-1) 
                                  12.5.48.0 - 12.5.55.255
Broad Band Networks / ESINET BROAD-BA16-56 (NET-12-5-56-0-1) 
                                  12.5.56.0 - 12.5.59.255
BROAD BAND NETWORK SERVICES BROAD-BA927-60 (NET-12-5-60-0-1) 
                                  12.5.60.0 - 12.5.63.255

So why do I see this lot from them? 11 routes where only one would suffice 
(1100% more than needed for anyone mathematically challenged)..

*  12.5.48.0/24      6453 1239 5778 12163 i
*  12.5.48.0/21      6453 1239 5778 12163 i
*  12.5.49.0/24      6453 1239 5778 12163 i
*  12.5.50.0/23      6453 1239 5778 12163 i
*  12.5.52.0/24      6453 1239 5778 12163 i   
*  12.5.54.0/23      6453 1239 5778 12163 i
*  12.5.56.0/23      6453 1239 5778 12163 i
*  12.5.56.0/22      6453 1239 5778 12163 i
*  12.5.58.0/24      6453 1239 5778 12163 i
*  12.5.59.0/24      6453 1239 5778 12163 i
*  12.5.60.0/22      6453 1239 5778 12163 i

I'm sure these arent the worst offenders but they were the first I came across 
in my sh ip bgp ...

So who's job is it to clean this up - I dont think proxy aggregation is a good 
idea as someone suggested, the only people in a position to fix this are the ISP 
themselves, their upstreams and their peers.

Steve