WDM全光网络中实时组播的分布式路由与波长分配算法

A Distributed Routing and Wavelength Assignment Algorithm for Real-Time Multicast in WDM All-Optical Networks

在WDM网络中 ,由于每条链路上可用波长是动态变化的 ,在考虑波长转换延迟的条件下 ,实现实时组播连接的路由与波长分配是十分困难的 假定WDM网络中每条链路有多根光纤 ,只有部分结点具有波长转换器且波长转换时间是不可忽略的 ,据此提出了一种用于建立实时组播连接的分布式路由与波长分配算法 该算法以Prim最小生成树算法为基础 ,生成一棵满足给定延迟时限的最小成本树 当最小成本树不能包括所有目的结点时 ,对剩余目的结点生成一棵最短延迟树 ,然后合并两棵树得到一棵组播树

Routing and wavelength assignment for online real time multicast connection setup is difficult due to the dynamic change of availabilities of wavelengths on links and the consideration of wavelength conversion delay in WDM networks Assuming that each link has multiple fibres, there are wavelength converters only at part of nodes and the conversion delay is not negligible A distributed routing and wavelength assignment algorithm for the setup of real time multicast connections is presented based on the above assumption The algorithm is based on Prim's MST (minimum spanning tree) algorithm It generates a sub minimal cost tree under a given delay bound first If there are nodes not included in the cost tree, a delay tree is generated to include the rest nodes The two trees are merged together The wavelength assignment uses least conversion and load balancing strategies