IEEE 802.1ah Provider Backbone Bridging (PBB) specification employs provider MSTP (PMSTP) to ensure loop avoidance in a resilient native Ethernet core. The usage of P-MSTP means failover times depend largely on the size and the connectivity model used in the network. The use of MPLS tunnels provides a way to scale the core while offering fast failover times using MPLS FRR. There are still service provider environments where Ethernet services are deployed using native Ethernet backbones. A solution based on native Ethernet backbone is required to achieve the same fast failover times as in the MPLS FRR case.
The Nokia PBB implementation offers the capability to use core Ethernet tunnels compliant with ITU-T G.8031 specification to achieve 50 ms resiliency for backbone failures. This is required to comply with the stringent SLAs provided by service providers in the current competitive environment. The implementation also allows a LAG-emulating Ethernet tunnel providing a complimentary native Ethernet E-LAN capability. The LAG-emulating Ethernet tunnels and G.8031 protected Ethernet tunnels operate independently.
The next section describes an applicability example where an Ethernet service provider using native PBB offers a carrier of carrier backhaul service for mobile operators.