Optical Packet Switching Compete In Problem-solving Research

With the development of optical fiber communication, the data rate of transmission has exceeded 10Tb/s on a single fiber. It forces the traditional optical-electrical-optical router to have huge capacity of RAM and high-speed signal processing ability. When the electronic processing speed can not match the data rate of transmission in fiber, the electronic bottleneck appears that restricts the further development of optical network. Optical packet switching becomes a best solution of conquering electronic bottleneck owing to smaller switching granularity, higher switching speed and the support to the upper protocol. In this paper, the technique of contention resolution in optical packet switching will be studied.In the part of contention resolution in wavelength domain, the schemes of contention resolution with wavelength conversion, SPC(single-per-channel), SPL(share-per-link)and SPN(share-per-node) are analyzed and compared. The results indicate that the packet loss probability of SPC is the limit of SPL and SPN. The packet loss probability of SPN is less than the SPL in the same number of wavelength converters. The number of wavelength converters that the SPN needs when the packet loss rate approaches to a fixed value, is less than that for the SPL.Then, we analyse the problem caused by unimproved distribution order of wavelength passages using FAA (First Available Algorithm) that is a LRWCs(Limited-Range Wavelength Converter) distribution algorithm in optical packet switching and bring a Minimum Degree First(MDF) algorithm that firstly assign the wavelength passage with the fewest arriving packets. Theory analyse indicate that the MDF algorithm can get the minimum packet loss probability that is same with FAA, and meanwhile it can greatly reduce the number of LRWCs. Simulations confirm compared with FAA, the MDF can save more LRWCs and fewer packet loss probability, especially in the condition of high load .Using MDF algorithm ,the number of LRWCs in the condition of high load is more than in the condition of low load when the packet loss rate approaches to a fixed value. Increasing the converter range of LRWCs could reduce the packet loss rate and meanwhile,...