From: Pavel Bykov (slidersv@gmail.com)
Date: Tue Mar 03 2009 - 17:09:46 ARST
Yes, you can do it like that.
Basically advertising route out of backup router only when primary goes
down.
But beware of another method - advertising more precise route out to one
peer, and more general one to the other.
Many ISPs (especially TIER 1s) are filtering prefixes based upon RIR
information, therefore this trick will get filtered somewhere.
But if you peer only with one ISP, this is great way to load balance.
On Tue, Mar 3, 2009 at 6:45 PM, Hotmail <hussamkibbi@hotmail.com> wrote:
> I didn't find the message yet in archive, but I believe it can be done by:
> neighbor{ip-address} advertise-map {map1-name} non-exist-map {map2-name}
> As map1-name is our local networks and map2-name will be the network
> between
> myself and ISP1
>
> Right?
>
> -----Original Message-----
> From: markom@gmail.com [mailto:markom@gmail.com] On Behalf Of Marko
> Milivojevic
> Sent: Tuesday, March 03, 2009 10:21 PM
> To: Hotmail
> Cc: ccielab@groupstudy.com
> Subject: Re: Other than AS-prepending?
>
> Hi,
>
> some time ago (few months) I wrote on ccie list about this subject.
> The solution is to use "ISP-specific communities" to make them prefer the
> traffic. Try searching for that message in the archive. I think it will be
> of help.
>
>
> --
> Marko
> CCIE #18427 (SP)
> My network blog: http://cisco.markom.info/
>
> On Tue, Mar 3, 2009 at 16:12, 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
> >
> > ______________________________________________________________________
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>
>
> Blogs and organic groups at http://www.ccie.net
>
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>
>
>
>
>
>
>
-- Pavel Bykov ---------------- Don't forget to help stopping the braindumps, use of which reduces value of your certifications. Sign the petition at http://www.stopbraindumps.com/Blogs and organic groups at http://www.ccie.net
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