Seamless migration from BGP-VPLS to EVPN

A solution is introduced for enabling staged migration from BGP-VPLS toward EVPN on a site-by-site basis for every VPN routing instance. In this solution, the PE devices running EVPN and VPLS for the same VPN routing instance and single-homed segments can co-exist. The solution supports single-active redundancy of multi-homed networks and multi-homed devices for EVPN PEs. With single-active redundancy, the participant VPN instances may span across both EVPN PEs and VPLS PEs as long as single-active redundancy is employed by EVPN PEs.