[c-nsp] BGP Multihomed Selective/Conditional Advertisement

[Tony]

--- On Sun, 26/10/08, tkacprzynski at SpencerStuart.com <tkacprzynski at SpencerStuart.com> wrote:

> From: tkacprzynski at SpencerStuart.com <tkacprzynski at SpencerStuart.com>
> Subject: RE: [c-nsp] BGP Multihomed Selective/Conditional Advertisement
> To: td_miles at yahoo.com, cisco-nsp at puck.nether.net
> Date: Sunday, 26 October, 2008, 3:54 AM
> I'm not sure if I can have multiple advertise-maps also,
> but can't find any documentation on it either. Does
> anyone else know?
> 

This is the best doco I could find:

http://www.ciscopress.com/articles/article.asp?p=169556&seqNum=2

Probably the most relevant section is this :

===
NOTE

A conditional advertisement does not create routes; it only withholds them until the condition is met. These routes must already be present in the BGP RIB.
===

Having read that, I don't think you're going to be able to do what you want with exist or nonexist maps, as they only control IF a prefix is advertised, not any of the other stuff about the prefix being advertised.