draft-sajassi-bess-evpn-vpws-fxc ("EVPN VPWS Flexible Cross-Connect Service")
https://www.ietf.org/archive/id/draft-sajassi-bess-evpn-vpws-fxc-03.txt
Two of the main motivations for service providers seeking a new solution are:
1) to reduce number of VPWS service tunnels by multiplexing large number of ACs across different physical interfaces instead of having one VPWS service tunnel per AC, and
2) to reduce the signaling of ACs as much as possible. Besides these two requirements, they also want
3- multi-homing and
4- fast convergence capabilities of [RFC8214].