MPLS networks offering PW or VPLS services may be interconnected with Ethernet networks implemented according to 802.1ah or 802.1Qay. The MPLS network may be a core and offer services to the Ethernet access networks, or vise-versa. Additionally, a mixture of different types of access networks may be interconnected by an MPLS core or an Ethernet core. Both network interworking and service interworking are provided. OAM fault detection may be implemented via maintenance entities extending across the network or end to end depending on the combination of networks and services offered by the networks.