Patent ID: 8717906

Claim:
A network relay device constituting a first network said network relay device comprising: a receiving unit for receiving a frame transmitted from an external network relay device constituting a second network different from the first network, wherein the frame is encapsulated on the way by another relay device at a boundary between the first network and the second network, and relayed as an encapsulated frame to the network relay device, which when the frame comprises a confirmation frame for a network operation, an administration, or a maintenance, includes in a protocol identifier an identifier indicative of the confirmation frame for the network operation, the administration, or the maintenance, a frame determination unit for receiving the encapsulated frame and referencing the protocol identifier included in the encapsulated frame to determine whether the encapsulated frame includes the confirmation frame for the network operation, the administration, or the maintenance; and a processing unit for performing any of the network operation, the administration, or the maintenance on the encapsulated frame, when the frame determination unit determines that the encapsulated frame includes the confirmation frame, wherein, before an encapsulation of the encapsulated frame, the frame includes each field of a destination address (DA) MAC address, a source address (SA) MAC address, and an Ether type, wherein, after the encapsulation, the encapsulated frame includes a DA B-MAC address and an SA MAC address, the DA MAC address, the SA MAC address, and the Ether type contained in an original frame, and wherein the first network comprises a network in accordance with IEEE802.1ah standard, wherein the second network comprises a network in accordance with IEEE802.1ad standard, wherein the protocol identifier comprises the Ether type, wherein the confirmation frame comprises an Ethernet OAM (operation, administration, and maintenance) frame, wherein the frame determination unit references the Ether type, to determine whether the frame includes the Ethernet OAM frame, and determines whether the frame is addressed to the network relay device.