Patent ID: 8004967

Claim:
A routing method for a ring network, the ring network comprising multiple connected nodes, the method comprises: by each node in the ring network, acquiring topology information of the ring network, obtaining under-ring routings learned by the other nodes from an under-ring network, calculating a main path and a backup path from the node to each under-ring routing according to the acquired topology information of the ring network, wherein, for each under-rinq routing, calculating the hop number of the left-hand connection to the node corresponding to the under-ring routing and the hop number of the right-hand connection to the node corresponding to the under-ring routing, selecting the one of the left-hand connection or the right-hand connection having the smaller hop number as the main path to the under-ring routing and the other as the backup path to the under-ring routing if the two calculated hop numbers are not equal, and otherwise, selecting one of the left-hand connection and the right-hand connection as the main path according to a predefined rule and the other one as the backup path if the two calculated hop numbers are equal, creating a Fast Rerouting (FRR) switch table, and switching between the main path and the backup path according to the FRR switch table when a failure occurs in the ring network.