Patent ID: 7075889

Claim:
A restoration method for restoring a flow of packets in a packet transfer network composed of a plurality of routers, comprising the steps of: a) setting a working route and a reserved route in the packet transfer network, wherein the reserved route branches from the working route at a start-point router; at each of routers other than the start-point router on the working route, b) determining whether a failure occurs in a link to a next-hop router on the working route; c) determining whether an incoming packet is to be protected or is not to be protected; d) when a packet to be protected is received in case of occurrence of the failure, sending the packet to be protected back to the start-point router, and when a packet which is not to be protected is received in case of occurrence of the failure, the packet not to be protected is not sent back to the start point router; and at the start-point router, e) when receiving back the packet to be protected, forwarding it to the reserved route.