Patent ID: 7499650

Claim:
A multiple-plane OBS node comprising: N input ports, N 1×N switches, N switching planes, N 2 fiber delay lines (FDLs), N optical couplers, and N output ports, each input port is connected with the input of a corresponding 1×N switches, the N outputs of each 1×N switch are connected with a corresponding input of each switching plane respectively, a corresponding output of each switching plane is connected with the input of the same corresponding optical coupler via a respective FDL, and each output port is connected with the output of a corresponding optical coupler, wherein N is an integer and N≧2; wherein each of the FDLs comprises: a 1×2 switch at the input of the FDL, N 2×2 switching units, and an optical coupler at the output of the FDL, two short fiber lines connect the output of the 1×2 switch with the input of the first 2×2 switching unit; a short fiber line and a basic delay unit connect the first 2×2 switching unit with the second 2×2 switching unit, the second 2×2 switching unit with the third 2×2 switching unit, . . . , and the (N−1)th 2×2 switching unit with the Nth 2×2 switching unit; two short fiber lines connect the output of the Nth 2×2 switching unit with the input of the optical coupler; wherein buffering policy adopted by each set of FDLs for each output port is as follows: when a burst arrives at a FDL, if the output port is busy, then the burst is put into the first basic delay unit of the FDL; and when the output port is free after the current burst's transmission is completed, the next burst to be output from the set of FDLs should be the one with the minimal value of a parameter Di, wherein Di refers to the distance from the burst in the respective FDL to its next 2×2 switching unit.