From: Uchil Perera (uchil.groupstudy@gmail.com)
Date: Tue Mar 03 2009 - 17:20:15 ARST
Hi,
The easiest way to do this is to advertise an aggregate and specific routes
from each location
For example
You have an ISP block of 1.1.0.0/16 and you assign 1.1.1.0/24 to site A and
1.1.2.0/24 to site B. You can advertise 1.1.1.0/24 and the aggregate (
1.1.0.0/16) from site A and 1.1.2.0/24 and the aggregate (1.1.0.0/16) from
site B. This makes sure incoming traffic to 1.1.1.0/24 will always use site
A as it is more specific then the aggregate advertised by site B, you do the
same on site B.If site A ISP link fails, traffic will match the aggregate
advertised from site B and reach site A through B.
H.T.H.
Rgds
Uchil
CCIE#18536
On Tue, Mar 3, 2009 at 9:42 PM, Hotmail <hussamkibbi@hotmail.com> wrote:
> Hi Experts,
>
> Is there a way to prefer incoming traffic other than as-prepening(or any
> other attribute like MED), by using conditional advertisment or some other
> features?
>
> The thing is that As-Prepending not always work for all routes, there is
> still some routes won't be prefered for any reason.
>
> So is there a way like to assume this BGP session (backup one(r2) ) to ISP2
> is down until the primary one(r1) to ther ISP1 really get down ?
>
> r1(Active)--EBGP-->ISP1 r1--ibgp---r2
> r2 (Standby)--EBGP-->ISP2
>
>
> Cheers,
> Hussam
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Mon Apr 06 2009 - 06:44:03 ART