Patent ID: 8346080

Claim:
An improved optical network system having (i) a plurality of nodes to which different wavelengths or positional spaces of a transmission line are allocated, each of the nodes being capable of receiving only an optical signal of the allocated wavelength or the allocated positional space and transmitting, to the other nodes, optical signals of the wavelengths or the positional spaces allocated to the other nodes and (ii) a ring network formed in the shape of a ring that performs time division multiplexing transmission of a plurality of optical signals from the plurality of nodes, wherein the improvement comprises: a plurality of time-division slots formed in the ring network for transmitting optical signals of the wavelengths or the positional spaces allocated to the individual nodes, said plurality of time-division slots including information indicating whether an optical signal to be transmitted exists in the time-division slot; and updating means in each of said plurality of nodes for updating without checking the information included in the time-division slot corresponding to a node that receives an optical signal from the node, said information with information indicating that the optical signal exists; and determining means in each of said plurality of nodes for: operating in the same clock cycle as that in which the updating means updates the information; reading the information having not been updated; and determining, on the basis of the read information, whether to transmit the optical signal in parallel with updating of the information by the updating means.