This section discusses the details of the emulated LAG Ethernet tunnels for PBB. The main solution components are depicted in Figure: Ethernet tunnel overlay which overlays Ethernet Tunnels services on the network from Figure: PBB-Epipe with B-VPLS over Ethernet tunnel.
For a PBB Ethernet VLAN to make efficient use of an emulated LAG solution, a Management-VPLS (m-VPLS) is configured enabling Provider Multi-Instance Spanning Tree Protocol (P-MSTP). The m-VPLS is assigned to two SAPs; the eth-tunnels connecting BEB1 to BCB-E and BCB-F, respectively, reserving a range of VLANs for P-MSTP.
The PBB P-MSTP service is represented in the BEBs as a combination of an Epipe mapped to a BVPLS instance as before but now the PBB service is able to use the Ethernet tunnels under the P-MSTP control and load share traffic on the emulated LAN. In our example, the blue-circle representing the BVPLS is assigned to the SAPs which define two paths each. All paths are specified as primary precedence to load share the traffic.
A Management VPLS (m-VPLS) is first configured with a VLAN-range and assigned to the SAPs containing the path to the BCBs. The load shared eth-tunnel objects are defined by specifying a member ports and a control tag of zero. Then individual B-VPLS services can be assigned to the member paths of the emulated LAGs and defining the path encapsulation. Then individual services such as the IVPLS service can be assigned to the B-VPLS.
At the BCBs the tunnels are terminated the next BVPLS instance controlled by P-MSTP on the BCBs to forward the traffic.
In the event of link failure, the emulated LAG group automatically adjusts the number of paths. A threshold can be set whereby the LAG group is declared down. All emulated LAG operations are independent of any 8031-1to1 operation.