This paper is concentrated on the following three aspects : ( 1 ) the researches about limited - range wavelength conversion , the contents include : the research about the rwa ( routing and wavelength assignment ) of xgm ( cross - gain modulation ) wavelength converters ; the performance analysis of wdm network with limited - range wavelength converters , which includes xgm and fwm ( four - wave mixing ) wavelength converters ; the research about the influence of the alternate rwa to the performance of wdm networks with limited - range wavelength converters 本文研究主要集中在3个方面： ( 1 )基于有限范围波长变换器的研究，具体内容包括：基于xgm ( cross - gainmodulation ，交叉增益调制)有限范围波长变换器的路由与波长分配算法的研究； xgm和fwm ( four - wavemixing ，四波混频)有限范围波长变换器网络的性能分析；备用路由与波长分配算法对有限范围波长变换器网络性能影响的研究。
In addition , a model is presented to analyse the blocking probability problem . by using alternative routing method with adaptive element , the new dynamic rwa algorithm guarantees low blocking probability a nd high tolerance of the network mistakes . a shorter delay time is achieved by considering the first k links information to find a available route 论文给出了分析rwa算法阻塞率的方法，提出的新rwa算法中路由采用了优化的含自适应成分的替代路由法，该算法既保证了网络低阻塞率的要求，又具有一定的网络容错能力，利用前k条链路信息的技术使得算法运行时间更短，在波长分配的问题上，算法应用优先级的方法以满足不同优先级别业务的需求。
This paper centers on the algorithms to construct low cost multicast routing trees with qos requirements . now , researches on multicast routing algorithm mainly focus on multicasting algorithm without constraints , delay - constrained and bandwidth reserved multicast routing . in this thesis , firstly , the existing heuristic algorithms for steiner tree problem are summarized ; secondly , a research and analysis is made on genetic algorithms and a kind of multicasting algorithm based on genetic strategy with two populations is proposed ; then , the group multicast routing problem with bandwidth constrained is studied , and by the idea of the algorithm for the kidnap problem , a global heuristic algorithm for the group multicast routing problem is presented ; at last , a new direction of the study , the multicast routing and assignment of wavelength in wdm optical network is studied , on the basis of analysis of the latest research results about raw problem , a multicast algorithm based on flow in wdm optical network is presented 本论文首先综述了无约束多播问题的基础，即最优steiner树问题及其启发式算法；接着对遗传算法进行了研究和分析，并且给出了一种基于双种群遗传策略的多播路由算法和一种求解k阶最小树的正交遗传算法；此外，本论文还研究了有带宽预留机制的组内多播路由问题，并且根据解决多重背包问题的算法思想给出了一种全局启发式组内多播路由算法；最后，本论文对多播路由问题的最新发展领域，即wdm光传送网中多播路由和波长分配问题进行了初步研究，分析了该问题及raw ( routingandassignmentofwavelength )问题的研究现状，并提出了wdm光传送网中基于流量的一种多播路由算法。
Next , a novel priority - based wavelength assignment algorithm in all - optical networks with partial wavelength conversion is proposed , based on link independent assumption and the method of calculating the network the blocks probability . it improves the routing and wavelength assignment presented by others . this algorithm fits the demand of different business for asking the grade of corresponding different services in the modern all - optical network than the original algorithm 其次研究了部分波长可变wdm网中支持优先级的波长分配问题,以及在此网络中网络阻塞概率的计算;基于链路波长占用独立性假设,改进了在部分波长转换wdm网中已有的rwa算法,提出了一种支持优先级的动态波长分配算法,该算法保证了较高优先级的光路建立请求具有较低的阻塞率,比原有算法更加适合现代光网络中不同业务请求对应不同服务等级的要求。
A key issue in networks design is to optimize routing and wavelength assignment ( rwa ) for lightpaths . rwa solves how to find out an appropriate lightpath and assign a wavelength reasonably in order to make full use of the limited resource and provide communication capability as large as possible 优化光通道的选路和波长分配( rwa )是网络设计的核心问题,其主要任务是寻找一条合适的光路并为之合理地分配波长,使有限的资源充分发挥作用,以提供尽可能大的通信容量。
