BellSouth prefix deaggregation (was: as6198 aggregation event)

Sun Oct 12 19:07:46 UTC 2003

> 
> IMHO, I think we should create a route-set obj like call 
> it... RS-DEAGGREGATES and list all the major irresponsible 
> providers's specific /24's in it...

CASE: Business has a /24 from X provider in order to multihome.
That /24 is de-aggregated from a /19, with this policy that
/24 may not be routed.

possible exception: When 2002-3 get passed by ARIN, this could even take
on new meaning. ARIN says they will use a single /8 for the handing
out of /22-/24 for multihoming end users.  will you then filter those 
/24's also?

Also:
What happens when that /24 for Business Y noted above is dual routed
by ISP A and ISP B, and ISP A's upstream filters but ISP B's does not?
Will there be asymmetric routing?

Finally: 
Can anyone from BellSouth, explain the end goal of the de-aggregation?

I suspect with 40 + ASs they may be rebuilding their network with a
recently announced list of new IP services and DSL growth as asked for
under the Federal government  Rural DSL regulations... (I'm not trying to defend
them, just giving some possibilities)

> So some ASes who wish to not accept deaggregated specifics 
> using RPSL can update their AS import policy to not import 
> RS-DEAGGREGATES...

> 
> Just my humble opinion..  Comments/critics welcome :)
> 
> -hc
> 
> -- 
> Haesu C.
> TowardEX Technologies, Inc.
> Consulting, colocation, web hosting, network design and implementation
> http://www.towardex.com | haesu at towardex.com
> Cell: (978)394-2867     | Office: (978)263-3399 Ext. 170
> Fax: (978)263-0033      | POC: HAESU-ARIN
> 
> 
> On Sun, Oct 12, 2003 at 11:26:49AM -0400, Jared Mauch wrote:
> > 
> > On Sun, Oct 12, 2003 at 01:02:57PM +0000, Stephen J. Wilcox wrote:
> > > 
> > > > Can anyone from BellSouth comment?  What if a few other 
> major ISPs were
> > > > to add a thousand or so deaggregated routes in a few 
> weeks time?  Would
> > > > there be a greater impact?
> > > 
> > > one word - irresponsible
> > 
> > 	This clearly stands out to me as a reason to keep and use
> > prefix filtering on peers to reduce the amount of junk in 
> the routing
> > tables.  If bellsouth needs to leak more specifics for load 
> balancing
> > purposes, fine, just make sure those routes don't leave 
> your upstreams
> > networks and waste router memory for the rest of us that 
> don't need to
> > see it.
> > 
> > 	- Jared
> > 
> > > > (Note: The above numbers are based on data from 
> cidr-report.org.  Some
> > > > other looking glasses were also checked to see if 
> cidr-report.org's view
> > > > of these AS's is consistent with the Internet as a 
> whole.  This appears
> > > > to be the case, but corrections are welcome.)
> > > > 
> > > > -Terry
> > > > 
> > > > > -----Original Message-----
> > > > > From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu] On 
> > > > > Behalf Of Terry Baranski
> > > > > Sent: Sunday, October 05, 2003 3:01 PM
> > > > > To: 'James Cowie'; nanog at merit.edu
> > > > > Subject: RE: as6198 aggregation event
> > > > > 
> > > > > 
> > > > > 
> > > > > James Cowie wrote:
> > > > > 
> > > > > > On Friday, we noted with some interest the 
> appearance of more 
> > > > > > than six hundred deaggregated /24s into the global routing 
> > > > > > tables.  More unusually, they're still in there 
> this morning.  
> > > > > > 
> > > > > > AS6198 (BellSouth Miami) seems to have been 
> patiently injecting 
> > > > > > them over the course of several hours, between 
> about 04:00 GMT 
> > > > > > and 08:00 GMT on Friday morning (3 Oct 2003).  
> > > > > 
> > > > > If you look at the 09/19 and 09/26 CIDR Reports, 
> BellSouth Atlanta
> > > > > (AS6197) did something similar during this time 
> period -- they added
> > > > > about 350 deaggregated prefixes, most if not all /24's.  
> > > > > 
> > > > > > Usually when we see deaggregations, they hit 
> quickly and they
> > > > > > disappear quickly; nice sharp vertical jumps in the 
> table size.
> > > > > > This event lasted for hours and, more importantly, 
> the prefixes 
> > > > > > haven't come back out again, an unusual pattern for 
> a single-origin
> > > > > > change that effectively expanded global tables by 
> half a percent. 
> > > > > 
> > > > > That AS6197's additions are still present isn't encouraging.
> > > > > 
> > > > > -Terry
> > > > > 
> > > > 
> > > > 
> > 
> > -- 
> > Jared Mauch  | pgp key available via finger from 
> jared at puck.nether.net
> > clue++;      | http://puck.nether.net/~jared/  My 
> statements are only mine.
> 
> 