US Patent 7885259 Deterministic multiprotocol label switching (MPLS) labels

Disclosed are, inter alia, methods, apparatus, computer-readable media, mechanisms, and means for deterministically determining MPLS labels as functions of addresses of Forwarding Equivalence Classes (FECs), and using these determined labels in the forwarding of packets. By each packet switching device in a network deterministically determining the same MPLS label to use for each FEC, each packet switching device knows what label will be used by the other packet switching devices, without running Label Distribution Protocol (LDP) or another label publishing protocol. Additionally, this knowledge extends to all packet switching devices in a network, not merely neighboring packet switching devices, which allows a packet switching device to specify a stack of labels to define a desired path through the network for explicit path routing and/or fast rerouting of traffic without having to previously establish a tunnel or path using Resource Reservation Protocol (RSVP), for example.