From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Oct 01 2003 - 15:31:57 GMT-3
No, this is not split-horizon. In fact it is much stricter than
the split horizon rule. An iBGP learned route cannot be advertised to
another iBGP neighbor. This behavior forces all iBGP sessions to be
fully meshed. Therefore you can learn a prefix from the closest source
from where the route is being originated. The exception to this rule is
route-reflection.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 708-362-1418 (Outside the US and Canada)
> -----Original Message-----
> From: Cristian Henry H [mailto:chenry@reuna.cl]
> Sent: Wednesday, October 01, 2003 11:39 AM
> To: Brian McGahan
> Cc: Ken.Farrington@barclayscapital.com; ccielab@groupstudy.com
> Subject: Re: BGP Experts Required here.
>
> But if this best route come from the iBGP neighbor, the receiver
router
> doesn't send back this route to this neighbor, right?, Is this
> slipt-horizon rule?
>
> Brian McGahan ha escrito:
> >
> > This behavior does not relate to split horizon. A BGP
speaking
> > device will only advertise its best routes. BGP does this both to
> > prevent traffic black holes and to minimize the size of the global
BGP
> > table.
>
>
> --
> Cristian E. Henry
> REUNA
>
> E-mail: chenry@reuna.cl
> Fono: 56-2-3370336
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