Patent ID: 8174963

Claim:
A data relay apparatus that recovers a failure in a network having a shared portion that is shared by a plurality of rings, relays a packet in the shared portion, and avoids occurrence of a loop path by setting at a portion other than the shared portion on each of the rings a block that blocks the packet and passes through a control packet used to control the network, the data relay apparatus comprising: a failure detecting unit to detect a failure in the network; a ring selecting unit to select from the rings a ring in which a failure is not detected by the failure detecting unit as a redundancy-providing ring used to provide redundancy for the shared portion; a transmitting unit to transmit, to only a data relay apparatus on the redundancy-providing ring selected from among a plurality of data relay apparatuses on the rings that relay the packet in the portion other than the shared portion on each of the rings, a trap packet that makes each of the data relay apparatuses release the block as the control packet, when the failure detecting unit detects a failure in the shared portion; a block setting unit to set the block at a port connected to the shared portion, wherein the ring selecting unit selects the redundancy-providing ring from the rings other than a ring whose portion except for the shared portion includes a failure detected by the failure detecting unit.