BGP - DMZ Link Bandwidth and Backdoor

We enable the feature on a border BGP router using the command bgp dmzlink-bw. With this command enabled, the BGP process will instruct the data plane to load-balance based on the bandwidth of the links used to connect to the external BGP peers. To select the links that are to be used for load-balancing, you configure the respective BGP peers using the command neighbor dmzlink-bw. The BGP process will consider the bandwidth on the links connecting to those peers when doing the unequal cost load-balancing. In Cisco terminology, those links are called the DMZ Links. The bandwidth is computed based on the bandwidth command configured on the respective interfaces, or based on the default administrative bandwidth.

R1# router bgp 65001
 bgp dmzlink-bw
 neighbor 12.1.1.2 dmzlink-bw

Backdoor

This tells BGP under the hood to not actually advertise that route out through BGP but to give it an administrative distance of 200. Thus, it will make the route less preferred than other routing protocol and allow too use different path.

R2#router bgp 100
network 150.1.77.0 mask 255.255.255.0 backdoor