Design and Implementation of an Ultra Fast Pipelined Wavelength Scheduler for Optical Burst Switching

Y. Chen, J.S. Turner, and Z. Zhai (USA)


Optical burst switching, OBS, wavelength scheduling, optical packet switching, wavelength routing


Optical Burst Switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over DWDM links. In OBS, before the transmission of data bursts, a Burst Header Cell (BHC) is transmitted through an out-of-band control plane, setting up and tearing down optical wavelength paths. Data bursts can remain in the optical data plane and pass through the network transparently. This paper is the first one to study the negative impact of control path overload in the OBS networks. Based on the study, the control path overload can be the performance bottleneck in the OBS networks, especially for systems with large channel counts. In order to meet the stringent performance requirements, we have designed and implemented an ultra fast pipelined wavelength scheduler that is able to process a burst request every two clock cycles, regardless of the number of WDM channels per link. The design has been implemented in Verilog HDL. Circuit level simulation results confirm the correctness of the design. The logic needed for the scheduler is simple enough so that a 500 MHz clock can be achieved in 130 nm process, allowing the scheduler to process a burst request every 4 ns.

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