VPLS Data Plane
In the data plane, the transported frames look the same as Ethernet frames in the AToM model. Two labels are imposed on the Ethernet frame. The top label or tunnel label identifies the tunnel (LSP) that the frame belongs to. In other words, it forwards the frame from the local or ingress PE to the remote or egress PE. The bottom label is the VC label, and it identifies the pseudowire. In other words, the egress PE looks at the VC label; it uses the VC label to determine to which attachment circuit (Ethernet port or VLAN interface) the frame should be forwarded onto. Figure 11-3 shows the Ethernet frame with two MPLS labels as it is transported across the MPLS network.
Figure 11-3. VPLS Data Plane
The ...
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