The Hardware Design And Implementation Of Control Module In The OBS Edge Node

With the comprehensive application of the WDM technology, the bandwidth problem of the transport network has been solved. Because of the explosive growth trend of Internet traffic, demanding a new optical switch to solve the lack of the switch ability in the node of transport network. Optical burst switch (OBS) is a compromising method giving attention to the advantages of both optical packet switch and optical circuit switch, therefore the OBS becomes one of the key issues in optical networks.The most important characteristic of OBS is adopting one-way resource reservation mechanism, and the control module in the edge node is one of the parts to implement the mechanism in the whole network. Two hardware design schemes which based the Just in time and Just enough time resource reservation protocols are reported in this paper, emphasizing the JIT protocol which is more complexity to the JET protocol in the edge node comparatively. A parallel structure based on the different hierarchies is adopted for the sake of increasing the throughput, Time Process Machine is proposed to deal with the time event, bus control module is designed to solve the request conflict between several modules, sending and receiving module of burst control packet and burst data packet are also interpreted detailedly.The design scheme bases on the FPGA chip and is compiled successfully in the Quartus II software. Timing analyse results show that the working clock in theory of the two types of the control module can get as much as 118.84 MHz and 123.73 MHz respectively. Through timing simulation and waveforms form oscillograph, it is indicated that the schemes can accomplish the function of the control module preferably, specially the disposal delay caused by module would not affect the actual offset time badly.