RFC7432 defines the MAC/IP advertisement NLRI (route type 2) for exchanging EVPN overlay end-hosts MAC addresses reachability information.  When an EVPN MAC/IP route contains more than one path to the same L2 destination, the EVPN MAC/IP best-path selection algorithm determines which of these paths should be considered as the best path to that L2 destination. 

EVPN EOS 4.31.0F BGP best-path