11-07-2012 05:38 PM - edited 03-04-2019 06:04 PM
Probably a lame question:
I have two routers connecting to two ISPs individually on BGP(same AS# at my side), I want to control which ISP link the Internet users will use to connect me. How can I do that? How can I control my BGP advertising to upstream so make one link is prefered to my IP subnet?
Thanks a lot.
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11-07-2012 07:13 PM
In this situation, AS Prepending may be prefered. Configure your non-preferred link by prepending your AS number a couple of times and apply outbound to your peer:
ip prefix-list LessPreferred permit 192.168.1.0/24
route-map LessPreferred permit 10
match ip address prefix LessPreferred
set as-path prepend
route-map LessPreferred permit 20
router bgp
neighbor
When the neighbor gets the advertisement from you, the less preferred route will have a longer as path and will be less preferred than the path through the other neighbor.
HTH,
John
11-07-2012 07:13 PM
In this situation, AS Prepending may be prefered. Configure your non-preferred link by prepending your AS number a couple of times and apply outbound to your peer:
ip prefix-list LessPreferred permit 192.168.1.0/24
route-map LessPreferred permit 10
match ip address prefix LessPreferred
set as-path prepend
route-map LessPreferred permit 20
router bgp
neighbor
When the neighbor gets the advertisement from you, the less preferred route will have a longer as path and will be less preferred than the path through the other neighbor.
HTH,
John
11-20-2012 06:50 PM
Thanks a lot.
11-20-2012 10:43 PM
Dear John,
I need same require , we are using three different ISPs Bandhwdith in Single Router (eBGP) and our require as given bellow.
We have 1.1.1.0/24
2.2.2.0/24
3.3.3.0/24
but i need 2.2.2.0/24 ip pools traffice from ISP-3 i have confgured as-path prepend of this ip pools on ISP-1 and ISP-2.
ip prefix-list ISP-3 seq 5 permit 2.2.2.0/24
route-map ISP-3 permit 10
match ip address prefix-list ISP-3
set as-path prepend my asn my asn my asn
router bgp my asn
nei ISP-1 x.x.x.x route-map ISP-3 out
nei ISP-2 y.y.y.y route-map ISP-3 out
but not work properly we are using IOS - flash:c3845-ipbasek9-mz.124-24.T.bin in my Cisco Router.
Please help for the same and how can i achive this.
Thanks in ADV,
11-21-2012 04:08 AM
Hi,
have you done a route refresh ? clear ip bgp * out
Regards.
Alain
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11-21-2012 08:43 PM
Dear Alain,
Yes i have done clear ip bgp * but not any effect , and i want to know this config is it right ?? or not to achive this ?? as per my requirement.
Pl help it is very URGENT for me...
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