Patent ID: 8737201

Claim:
A data relay apparatus that carries out data relay in a ring communication network in which data that includes a path identifier and is transferred according to the path identifier exists, comprising: a receiving part that receives the data; an information storing part that stores the path identifier in association with a reception direction and a transmission direction of the data and information indicating whether a data path determined by the path identifier, in which the data is transferred in the ring communication network, is a usual path for an ordinary occasion and a reserve path for an occasion of a communication failure; a switching part that compares the path identifier included in the received data and the path identifier stored by the information storing part, determines a path in which the data is to be received and transmitted and switches the transmission direction of the data between a transmission direction of the usual path and a transmission direction of the reserve path based on a reception direction of a failure notification message that is received when the communication failure occurs and whether a switching inhibition message that is transmitted concerning the communication failure is received; and a transmission part that transmits the data in the transmission direction that is switched by the switching part, wherein the switching part compares the reception direction of the failure notification message and a previously set transmission direction of the data stored in the information storing part, and switches the transmission direction of the data based on a result of the comparison and on whether the switching inhibition message is received.