The pseudowire identifier VC ID in an LDP-signaled VPWS also has significance in an LDP-signaled VPLS.
In an LDP-signaled VPLS, each pseudowire may be configured with the same VC ID, or each pseudowire may be configured with a different VC ID. RFC 4762 allows both configurations, but recommends the former. For the former, the VC ID is considered the VPLS ID for the VPLS.
A VC ID is locally significant on a PE, but is not globally significant. In other words, two pseudowires with the same VC ID, say 100, one between PEa => PEb and the other between PEx => PEy, are independent of each other. No connection exists between the two pseudowires.
ForwarderEndpoints are peers only when both of them use the same VC ID and point to each other’s IP address. The combination of VC ID and peer IP address for a ForwarderEndpoint is globally unique.