Contetion Resolution Strategies In OBS Networks With Limited Wavelength Conversion Capabilities

A backbone network with speedy connection rates and exceedingly high data transfer rate is desired for satisfying the dramatic increase in the Internet traffic and suiting for the bursty traffic of diversity. Therefore the broadband communication network is going through development to set up a transparent, effective all-optical network, in which optical switching technologies play an important supporting role. As the technology of Optical Burst Switching, which uses a medium switching granularity and a single-way signaling protocol, is taking in the strengths of Optical Circuit Switching and Optical Packet Switching while avoiding their shortcomings, it's hopeful to become commercial.It's not feasible to equip each node with a full wavelength converter in an OBS network due to their high costs and immature technologies. As a result, it's of great significance to research upon the OBS networks with limited wavelength conversion capability.The major work in this thesis is focusing on the contention resolution strategies in OBS networks with Limited Wavelength Conversion Capabilities. The routing selection algorithm, signaling protocol and wavelength selection algorithm are comprehensively and profoundly analyzed with improved algorithms put forward in each respect.As for the routing selection part, with the study of expressions for calculating the blocking rate of a single node with limited wavelength conversion capability, an expression for the overall blocking rate is derived, which is taken as the target by a common integer linear programming model. A new routing selection algorithm based on integer linear programming is then presented, which shows a better performance than the widely used shortest path algorithm.Concerning the signaling protocol technology, a new channel dispatching scheme with the name of Wavelength Amend-on-Demand is brought forward, struggling to figure out burst contentions happening at nodes with no wavelength conversion capability. Based on this scheme, Contention-based Limited Signaling Protocol is carefully designed afterwards. The new signaling protocol retrieves more data bursts than traditional signaling protocols, thus leads to a lower overall blocking rate.For the respect of wavelength selection, after a comprehensive analysis in traditional algorithms together with their features, a new distributed, adaptive algorithm, namely the Priority-based Wavelength Assignment-leg algorithm is put forward, which promises a lower overall blocking rate.