This article provides a step to check when there is a DCI and the border leaf is advertising a route, but the leaf on the other DC is not installing the route.

Setup as below:

Border leaf DC1 10.181.14.4------------ Border leaf DC2 172.28.247.7 ------ leaf2-DC2 172.28.247.34 lo0 --- server 00:00:00:00:00:00

The border leaf on DC2 is advertising the mac/ip of the server 00:00:00:00:00:00 connected in leaf2-DC.

root@Border-leaf2DC2> show route table bgp.evpn.0 advertising-protocol bgp 10.181.14.4 | match 00:00:00:00:00:00

2:172.28.247.34:65534::1140621::00:00:00:00:00:00/304 MAC/IP

When checking the output from Border leaf DC1 > show route table bgp.evpn.0 receiving-protocol bgp 172.28.247.7 | match 00:00:00:00:00:00 , nothing is received.

A possible reason is that the route target is not matching, or the leaf2-DC2 is not reachable from Border leaf DC1.

Suggested commands:

> show route table bgp.evpn.0 receiving-protocol bgp 172.28.247.7 hidden extensive| find 00:00:00:00:00:00

This will display the below information:

  2:172.28.247.34:65534::1140621::00:00:00:00:00:00/304 MAC/IP (1 entry, 0 announced)
     Import Accepted
     Route Distinguisher: 172.28.247.34:65534
     Route Label: 1140621
     ESI: 00:00:00:00:00:00:00:00:00:00
     Nexthop: 172.28.247.34
     AS path: 65086007 65086000 65086035 I 
     Communities: target:1140621L:1 encapsulation:vxlan(0x8)

In this output, make sure the next hop is reachable from the receiving device, in this scenario Border leaf DC1. And also make sure the vrf target is matching. If the next hop is not reachable, the route will not be installed.

In my scenario, the next hop 172.28.247.34 was not reachable from Border leaf DC1, after advertising the lo0 from the leaf the route was received properly and there was reachability between DC.