What you have done controls

CSCO12754306 · ‎03-13-2017

Hi im trying to control the inbound traffic from internet in a multihomed environment with two different ISP and 2 CPE`s using BGP . Both ISP are sending me default route so i`m using a route map (in) with the two bpg neighbors with the local preference 150 for the primary inbound and loc pref 100 for the back up but this is not working.

I found this on cisco web as an example , not working in real network:

Primary

ip as-path access-list 1 permit ^400$

neighbor 192.168.42.4 route-map AS-400-INCOMING in

route-map AS-400-INCOMING permit 10
match as-path 1
set local-preference 150

Sec

neighbor 192.168.31.3 route-map AS-300-INCOMING in

route-map AS-300-INCOMING permit 10
match as-path 1
set local-preference 100

ip as-path access-list 1 permit ^300$

Anyone know if it is possible to control inbound traffic with two different ISP`S in a real network?

THANKS

( SORRY FROM MY ENGLISH)

Philip D'Ath · ‎03-13-2017

What you have done controls which path you are going to use outbound. You need to do path pre-pending to try and influence which path the internet takes to you. The more you prepend the less attractive that path is.

For example, if your ASN was 12345:

route-map isp-out permit 10
  set as-path prepend 12345 12345 12345
...
router bgp 12345
  neighbour a.a.a.a route-map isp-out out

Multimohed service