IEEE 802.1ah draft standard (IEEE802.1ah), also known as Provider Backbone Bridges (PBB), defines an architecture and bridge protocols for interconnection of multiple Provider Bridge Networks (PBNs - IEEE802.1ad QinQ networks). PBB is defined in IEEE as a connectionless technology based on multipoint VLAN tunnels. IEEE 802.1ah employs Provider MSTP as the core control plane for loop avoidance and load balancing. As a result, the coverage of the solution is limited by STP scale in the core of large service provider networks.
Virtual Private LAN Service (VPLS), RFC 4762, Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling, provides a solution for extending Ethernet LAN services using MPLS tunneling capabilities through a routed, traffic-engineered MPLS backbone without running (M)STP across the backbone. As a result, VPLS has been deployed on a large scale in service provider networks.
The Nokia implementation fully supports a native PBB deployment and an integrated PBB-VPLS model where desirable PBB features such as MAC hiding, service aggregation and the service provider fit of the initial VPLS model are combined to provide the best of both worlds.