System and method of implementing lightweight not-via IP fast reroutes in a telecommunications network

摘要

A system, method, and node for implementing lightweight Not-via Internet Protocol fast reroutes of a packet in a telecommunications network between a first node and a destination node. The method determines a shortest path between the first node and the destination node and two redundant trees between the first node and the destination node. Each redundant tree provides an alternate path from the first node and the destination node. When a failure in a link between the first node and the destination node is detected, the packet is forwarded to the destination node via a first redundant tree, and if not available, via a second redundant tree. If the second redundant tree is not available, the packet is dropped. If no failure in the link between the first node and the destination node is detected, the packet is sent via the determined shortest path to the destination node.

主权项

1. A method of routing packets in a telecommunications network between a first node and a destination node, the method comprising the steps of:
determining a next hop in a shortest path between the first node and the destination node; computing a first maximally redundant tree and a second maximally redundant tree between the first node and the destination node, each of the first maximally redundant tree and the second maximally redundant tree providing an alternative path between the first node and the destination node, each alternative path sharing a minimal number of nodes with the other alternative path; detecting if a failure exists between the first node and the destination node; and if no failure exists, forwarding the packet along the shortest path between the first node and the destination node; if a failure exists, forwarding the packet via the first maximally redundant tree after encapsulating the packet using a first loopback address, the first loopback address identifying the destination node and identifying the first maximally redundant tree as the active forwarding tree; if a failure exists and the first maximally redundant tree is not available, forwarding the packet via the second maximally redundant tree after encapsulating the packet using a second loopback address, the second loopback address identifying the destination node and designating the second maximally redundant tree as the active forwarding tree; and further comprising the step of calculating next-hops only in either the first maximally redundant tree or the second maximally redundant tree instead of calculating a complete routing of the first maximally redundant tree or a complete routing of the second maximally redundant tree.