Automatic protection switching method, device and system

A computer program product comprising a non-transitory readable storage medium having a program code stored thereon for use by a first protection switching node, wherein a protection group comprises the first protection switching node and a second protection switching node, and at least two transmission paths between the first protection switching node and the second protection switching node;

• a mapping relationship between a path bandwidth combination and a channel allocation policy is configured on the first protection switching node;
• and the path bandwidth combination is formed by bandwidths of the at least two transmission paths, the program code comprising:
• instructions for determining that the bandwidth of at least one of the transmission paths changes;
• instructions for obtaining a final path bandwidth combination according to the bandwidth of the transmission path whose bandwidth changes, wherein the final path bandwidth combination is formed by bandwidths of the at least two transmission paths after the bandwidth of at least one transmission path changes;
• instructions for querying the stored mapping relationship between the path bandwidth combination and the channel allocation policy according to the final path bandwidth combination, and determining the channel allocation policy corresponding to the final path bandwidth combination;
• and
• instructions for performing channel switching according to the channel allocation policy corresponding to the final path bandwidth combination.