Light trees: optical multicasting for improved performance in wavelength routed networks
Light trees: optical multicasting for improved performance in wavelength routed networks
复制标题
DOI：
10.1109/35.747251
复制
发表时间：
1999-02
期刊：
影响因子：
--
通讯作者：
L. Sahasrabuddhe;B. Mukherjee
中科院分区：
文献类型：
--
作者：
L. Sahasrabuddhe;B. Mukherjee
我们在波长路由光网络中引入光树的概念。光树是光路的点对多点概括。光路是将源节点处的发射器连接到目标节点处的接收器的点对点全光波长通道。光路通信可以显着减少数据包必须经过的跳数（或光路）；而这种减少反过来又可以显着提高网络的吞吐量。我们通过在路由节点处合并光多播功能来扩展光路概念，以增加网络的逻辑连接性并进一步减少其跳跃距离。我们将这种点对多点扩展称为光树。光树不仅可以为单播流量提供改进的性能，而且它们自然可以更好地支持多播流量和广播流量。在本研究中，我们将重点关注轻树在单播和广播流量中的应用和优势。我们将基于光树的虚拟拓扑设计问题表述为具有两个可能目标函数之一的优化问题：对于给定的流量矩阵，（i）最小化网络范围内的平均数据包跳跃距离，或（ii）最小化网络中收发器的总数。我们证明，就上述两个目标而言，基于最佳光树的虚拟拓扑比基于最佳光路的虚拟拓扑具有明显的优势。
We introduce the concept of a light-tree in a wavelength-routed optical network. A light-tree is a point-to-multipoint generalization of a lightpath. A lightpath is a point-to-point all-optical wavelength channel connecting a transmitter at a source node to a receiver at a destination node. Lightpath communication can significantly reduce the number of hops (or lightpaths) a packet has to traverse; and this reduction can, in turn, significantly improve the network's throughput. We extend the lightpath concept by incorporating an optical multicasting capability at the routing nodes in order to increase the logical connectivity of the network and further decrease its hop distance. We refer to such a point-to-multipoint extension as a light-tree. Light-trees can not only provide improved performance for unicast traffic, but they naturally can better support multicast traffic and broadcast traffic. In this study, we shall concentrate on the application and advantages of light-trees to unicast and broadcast traffic. We formulate the light-tree-based virtual topology design problem as an optimization problem with one of two possible objective functions: for a given traffic matrix, (i) minimize the network-wide average packet hop distance, or (ii) minimize the total number of transceivers in the network. We demonstrate that an optimum light-tree-based virtual topology has clear advantages over an optimum lightpath-based virtual topology with respect to the above two objectives.