In an LDP-signaled L2VPN, the MPLS Topology Server creates a ForwarderEndpoint instance for each discovered virtual circuit identifier (VC ID). The VC ID identifies a particular pseudowire and represents the two virtual circuits that are associated with the pseudowire. One virtual circuit is carried over an outgoing LSP, and the other is carried over an incoming LSP. Together, the two virtual circuits provide bidirectional communication for a customer.
In a BGP-signaled L2VPN, the MPLS Topology Server creates a ForwarderEndpoint instance for each discovered incoming VC ID/ outgoing VC ID pair. The incoming VC ID identifies one virtual circuit of a particular pseudowire, and the outgoing VC ID identifies the other virtual circuit.