| With the rapid development of information technology, optical fiber communication based on WDM has become a mainstream way to support the communication transmission networks. The unicast routing scheme is one of the key technologies in optical backbone networks based on WDM technology. At present, this problem is devided into two sub-problems to be solved separately among most of the existing solutions, but it may exclude the optimal solution. In addition, these algorithms assume that the physical layer is lossless, but in reality, the accumulation of physical impairment on the optical signal can not be ignored. For multicast applications in optical networks, the algorithm based on spanning tree has been extensively studied. However, these algorithms can not reach the multicast capacity. Thus, it is necessary to explore new methods to improve the multicast capacity. The invention of network coding can just meet this requirement. As the characteristics of optical network itself, the existing network coding algorithms in the wireless network or copper network can not be used directly. It is very important to design the network coding algorithm that fits for optical networks. In order to provide reliable access service for terminal user, the corresponding access network needs to be built. Now, wireless access network (WAN) and local area network (LAN) are the most widely used.This dissertation focuses on the study of unicast routing in optical backbone networks, multicast communication based network coding and access network problem.The main research points and innovations are outlined as follows:(1) The multi-path routing algorithm is investigated. By introducing the concepts of distance among paths and distance between link and path, a multi-path routing algorithm based on the distance among paths is proposed. This algorithm gives a good foundation for the routing and wavelength assignment problem in optical networks.(2) The integer linear programming is investgated. In order to deal with the fractional solution of the relaxed integer linear programming, randomized rounding algorithm is used. We prove this algorithm can provide sub-optimal solution close to the optimum with high probability theoretically.(3) A novel routing and wavelength assignment algorithm is proposed, and it depends on multi-path routing algorithm based on the distance among paths and randomized rounding algorithm. In addition, the physical impairment is considered indirectly. The simulation results prove that the performance of the proposed algorithm is superior to the decomposition method.(4) The multicast application based on network coding in optical-wireless hybrid networks is investigated. The discrete characteristic of optical fiber and the QoS requirement of wireless users are considered together in the problem formulation, and the more generalized convex objective function is employed. Thus, the whole problem is formulated into a mixed integer non-linear programming (MINLP).(5) A two-stage online distributed optimization algorithm is proposed to solve the above MINLP problem. It divides the original problem into two sub-problems:network coding in optical networks; gateway selection, wireless user assignment and bandwidth allocation. For the first sub-problme, a novel dual decomposition algorithm is proposed, and it can make source adjust its sending rate dynamically. For the second sub-problem, the generalized bender decomposition method is used, and this algorithm has less number of iterations. The complexity of the proposed two-stage optimization algorithm is polynomial, so it is feasible for the actual multicast application.(6) A novel forwarding protocol for bridge is proposed. It can forward frames with different priorities using different paths based on hierarchical MAC address. This protocol can reduce complexity of forwarding process and storage overhead. The simulation results show that the proposed protocol can improve the throughput of LAN, and decrease the length of forwarding path at the same time.
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