BGP route-map prepend configuration examples

[juan-ruiz]

I have two main networks connected to an MPLS cloud.

Network A is the corporate facility it has its own internet.

Network B is the collocation facility it also has its own internet.

On the MPLS cloud I have 100 remote sites that use the internet out of corporate.

I would like to use the internet out the colo site for the remote locations and have the corporate site be the backup.

The BGP configurations for corporate and colo is below.

Corporate router BGP setup

router bgp 65001

network 0.0.0.0 mask 0.0.0.0

network 172.16.0.0 mask 255.255.254.0 ( I do not want to prepend the 172.16.0.0/23 network)

redistribute static metric 254

neighbor 152.176.58.193

remote-as 65000

Colo router BGP setup

router bgp 65001

network 0.0.0.0 mask 0.0.0.0

network 172.16.11.0 mask 255.255.255.0

no auto-summary

neighbor 147.225.85.213 remote-as 65000

I believe the best solution is to perform a BGP prepend at the corporate site.

Can someone assist me with a sample route-map using the above information that applies to corporate?

Thanks a lot

Juan

[juan-ruiz]

hi Telstra,

My goal is to have remote sites use the colo as the primary path.

Currently that is working and if the MPLS link is down the remote sites will shift to the corporate.

The only route lost is between corporate and colo.

Thanks

[juan-ruiz]

Hi Peter,

I like the change of Admin distance on a specific network.

Corporate network I want to advertise is 172.16.0.0/23.

The colo network I want to advertise is 172.16.11.0/24.

At corporate I could use under the bgp configuration

distance 254 172.16.11.0 0.0.0.255

and at colo I could use

distance 254 172.16.0.0 0.0.254.255

If I understand this properly the OSPF routes will be preferred and I can keep these networks over the metro E.

After looking at the distance command I do not see an option to specify the neighbor just the IP source address and the wild card bits. Tell me if I'm missing something.

[Edison Ortiz · Accepted solution]

The IP source address will be your neighbor IP so if your neighbor is 172.16.11.1 and you want to change the distance for all routes coming from that neighbor, the syntax is:

distance 254 172.16.11.1 0.0.0.0

Keep in mind, all BGP routes - eBGP and iBGP will be modified to the new administrative distance.

HTH,

__

Edison.

[juan-ruiz]

Edison and everyone on the thread thanks for your inputs

I used the distance command with a higher AD than ospf specified the peer and used an access-list for the specific route I wanted the AD increase only and it worked fine.

Many thanks

Juan