In Multiprotocol Label Switching (MPLS), the physical path selected by a Label Edge Router (LER) for a flow of packets between common endpoints and based on the Forwarding Equivalence Class (FEC) associated with the packet flow. Using a Label Distribution Protocol (LDP), the LER distributes to Label Switched Routers (LSRs) in the core the individual link selections that comprise the end-to-end path selection. The LER inserts labels into the headers of the individual packets in the flow. Each LSR in the core uses the label of the incoming packet to select the outgoing port and link, and swaps that label for a new label, which the downstream LSR uses to select the next port and link, and so on. See downstream, FEC, flow, header, label, LDP, LER, link, LSR, MPLS, packet, path, and port.