Re: [apops] Re: The Mandatory One Reply To This Weeks: The Cidr Report

[Joe Abley <jabley@automagic.org>]

On Wed, Mar 21, 2001 at 02:43:10PM -0800, Christian Nielsen wrote:
> On Wed, 21 Mar 2001, Joe Abley wrote:
> > The solution of advertising a large number of prefixes in different
> > ways to different adjacent networks is one way of accomplishing the
> > policy dissemination; however, one problem is the large amount of
> > prefix bloat associated with it that the whole network gets to see.
> 
> right. that is correct. i guess i can better understand this if they, the
> end user/edge network, would run BGP.
> 
> *>i148.182.0.0      209.1.40.63                  1000      0 1 16779 1221 i
> *>i148.182.16.0/24  209.1.40.63                  1000      0 1 16779 1221 ?
> *>i148.182.17.0/24  209.1.40.63                  1000      0 1 16779 1221 ?
> *>i148.182.18.0/24  209.1.40.63                  1000      0 1 16779 1221 ?
> 
> i have no problems seeing
> 
> * i148.182.12.0/22  209.1.220.156                1000      0 5727 1221 4740 4740 4740 4740 i

I think the issue here is you are only seeing part of what 122 may be
trying to do by your single view. If you can imagine other views of the
network where those /24s have different attributes, you can see how
there might be some method behind the madness; the deaggregation in
that case is a method for 1221 to influence routing in remote ASes in
order to do it's own inter-AS traffic engineering.

Note that I have no real knowledge of what 1221 is doing, or why. However,
Geoff is in Minneapolis presenting on exactly these topics and it seems
entirely possible that the two observed phenomena are related :)


Joe
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