Dear Andrew
Thanks , i will try it.
One more thing is that suppose if i will not enable BGP for my main
provider(ISPA-keeping static announcement as it is.) and i will only
configure BGP with my backup provider( ISPB)
and announceing my networks with AS prepends. Will it work????
Thanks
pp
----- Original Message -----
From: "Andrew Fort" <afort@choqolat.org>
To: "pankaj" <pankaj@worldgatein.net>
Cc: <cisco-nsp@puck.nether.net>
Sent: Tuesday, November 20, 2001 12:04 PM
Subject: Re: [nsp] BGP Multihoming -how to announce backup route???
> On Tue, Nov 20, 2001 at 11:05:06AM +0530, pankaj wrote:
> >
> > Now i want to receive traffic of two subnet A and B
> > from ISP A, Subnet C, D from ISPB .
> > If Isp A fails all traffic should come from B and if ISP B
> > fails all traffic should come from ISPA.
>
> announce all prefixes to both providers, with route-maps that prepend your
AS to the "backup" provider for the prefixes you wish the provider to be
backup for.
>
> e.g. if you're AS100, your ISP-A is AS200, your ISP-B is AS300..
>
> ip prefix-list ISP-A-backup permit 10.10.0.0/16
> ip prefix-list ISP-B-backup permit 10.11.0.0/16
>
> ip prefix-list announce permit 10.10.0.0/16
> ip prefix-list announce permit 10.11.0.0/16
>
> route-map ISP-A permit 10
> match ip address prefix-list ISP-A-backup
> set as-path prepend 100
>
> route-map ISP-B permit 10
> match ip address prefix-list ISP-B-backup
> set as-path perpend 100
>
> router bgp 100
> network 10.10.0.0 mask 255.255.0.0
> network 10.11.0.0 mask 255.255.0.0
> neighbor 1.2.3.4 remote-as 200
> neighbor 1.2.3.4 next-hop-self
> neighbor 1.2.3.4 prefix-list announce out
> neighbor 1.2.3.4 route-map ISP-A out
> no auto-summary
>
> dont forget to have an IGP/IBGP route for each of the network/mask pairs
you have listed in the bgp router, etc, etc.
>
> for more, read:
> http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/icsbgp4.htm
>
> and check out the stuff in:
> http://www.cisco.com/public/cons/
>
> -amf
>
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