中文摘要：

针对弹性光网络中业务的选路、频谱分配进行了研究，考虑到物理节点对业务安全性的影响，建立了以满足业务最低安全级别要求为约束、以最小化网络中最大占用频隙号为优化目标的全局约束优化模型。为有效求解该约束优化模型，设计了全局优化算法。将疏导后的业务按照某种排序策略进行排序，为每个业务选择K条满足业务最低安全级别要求的路径。利用改进的遗传算法为每个业务选择合适的路径并确定最优的频谱分配方案，使得网络中最大占用频谱号最小。为验证该算法的有效性，在不同的网络拓扑中进行了仿真，结果表明，所设计的算法可实现高效的频谱分配。

英文摘要：

Routing and spectrum allocation for connection requests in elastic optical networks are investigated. Considering the influence of physical nodes on the security, a global constrained optimization model is established, which is with the requirement of meeting the minimum security level as the constraint and with the maximum sequence number of frequency slots in networks as the optimization goal. In order to solve the constrained optimization model effectively, a global optimization algorithm is presented. The connection requests groomed are sorted according to a specific sorting policy. K paths, which satisfy the minimum security level requirement, are selected for every connection request. To minimize the maximum sequence number of frequency slots, the improved genetic algorithm is employed to determine the optimal routing and spectrum allocation scheme. In order to verify the validity of the proposed algorithm, simulations are conducted in different network topologies, and the results show that the efficient spectrum allocation can be achieved by the proposed algorithm.