| With the great development of network applications, new business emerges in endlessly.Because the traffic sharp increases in the optical communication network, the transmissionbandwidth of the network has higher requirements. The development of wavelength divisionmultiplexing (WDM) technology provides the optical network a huge bandwidth, and it willbecome the core backbone network transmission technology. With the continuous growth ofthe Internet business, the information exchange speed and the network bandwidth increase. Inorder to overcome the "electronic bottleneck", an optical burst switching (OBS) technology isproposed. OBS technology has moderate exchange granularity, strong flexibility andmoderate difficulty, so it has been considered a reliable optical switching technology in thefuture optical network. In OBS networks, two or more bursts request to reserve resources atthe same time and on the same wavelength of the same output port, they will produce thecontention of bursts. Excogitating the effective contention resolution methods which based ondifferential network statuses will has the great significance for the OBS network’s resourceutilization, throughput, etc.The architecture and function of OBS network are studied in this paper. First of all, wecombine a burst segmentation mechanism based on priority with a deflection routingmechanism, a burst segmentation-deflection routing contention resolution mechanism basedon priority in OBS networks is proposed. A deflection routing mechanism based on priority, adeflection routing mechanism based on priority and burst loss threshold, parameter tunable,load balancing, probability are carried out by the mathematical modeling and simulation.Simulations show that the schemes can improve the performance of OBS networks.Secondly, a burst segmentation-optical buffer contention resolution mechanism based onpriority in OBS networks of a single-wavelength channel system and a multi-wavelengthchannel system is proposed according to the wavelength channel data of the core node andnetwork load. Simulations show that the mechanism can reduce the burst loss probability ofentire networks. It also can efficiently reduce the delay, and reduce the offset time deficit onQoS guarantee. So the schemes can improve the performance of OBS networks.Thirdly, the resource reservation mechanism based on window with continuous-timevariable offsets and the preemption window mechanisms based on priority in emulated-OBSnetwork are proposed. The former sets a resource reservation window in the control channelof the emulated-OBS core routers, and it will determine whether to allow control bursts to reserve the link resource to data bursts. The latter sets a preemption window in the controlchannel of the emulated-OBS core routers, and will determine whether to allow high-prioritybursts to preempt low-priority bursts. Simulations show that the two schemes can improve theperformance of OBS networks.At last, we propose the tail of competition burst data packet or the head of original burstdata packet segmentation scheme. A composite burst assembly scheme combines packets ofdifferent classes into the same burst, placing the highest priority packets in the middle andlow priority packets at the tail and the head of the burst. The priority lowers gradually fromthe middle of the burst to the ends. Results show that the composite burst assembly schemecan adapt to the flexible network system. |
