通信工程文献翻译——摘要：随着波分复用技术的成熟和多播应用日益普及，支持在波分复用层多播，成为一个重要而又富有挑战性的课题。为了减少波长通道的数量，有效地达到多点传送，交换节点以光分裂的和波长转换的能力，开发虚声源(VS)结点。本文给出一个WDM网络，一个正整数k和一个组播组请求，在虚拟资源安置（VSP）的波分复用网络的问题进行了研究，这个目的是确定VS节点的位置，组播路由和分配组播请求波长，从而尽量减少使用的波长通道数。由于VSP问题是一个困难的问题，采用遗传算法（GA）提出了解决的办法。.在遗传算法中，二进制位的数组用来表示对网络的VS节点的位置。对于一个给定的位置与节点，有三个多播路由的方法：核心为基础的树（CBT）的，链路不相交CBT的（LDCBT）和分层图（LG），并用来构建多播请求共享树。构建一个多播树（MTC）的算法，用于构造给定的多播树的，而部分的波长分配（SBWA）算法，用于确定组播波长分配树。另外，在遗传算法，提出了几个交叉和变异算子开发并用于产生后代。仿真结果表明，该遗传算法与LG或CBT组播方法同时应用可以得到更好的结果。

关键词：波分复用，多播传送，虚拟资源，遗传算法，虚拟资源安置。

1.引言

人们普遍认为，下一代互联网将在很大程度上以波分复用（WDM）为基础的[1]骨干网。多播是信息从一个源传送到多个目的地，并同时为许多宽带服务，如视频会议，特别是重要的远程教育和网上广播。因此，未来的WDM网络组播支持也很重要。在WDM，进行数据包从一个源节点的唯一目的节点波长，通过其中的数据信号的光路由和无电再生交换节点的传递域。光路是在WDM网络通信的基本机制[1，2]。为了避免碰撞，没有两个相同的光路是通过使用相同的波长.......

abstract

As WDM technology matures and multicast applications become increasingly popular, supporting multicast at the WDM layer becomes an important and yet challenging topic. In order to reduce the number of wavelength channels to achieve the multicast effectively, switching nodes with light-splitting and wavelength-converting capabilities denoted as virtual source (VS) nodes are developed. In this paper, given a WDM network, a positive integer k and a set of multicast requests, the VS placement (VSP) problem on WDM networks is studied; the goal is to determine the locations of the VS nodes, the multicast routing and assigned wavelengths of multicast requests so as to minimize the number of used wavelength channels. Since the VSP problem is a hard problem, a genetic algorithm (GA) is proposed to solve it. In the proposed GA, a binary-bit array is used to represent the locations of the VS nodes on network. For a given locations of VS nodes, three multicast routing methods: core-based tree (CBT), link-disjoint CBT (LDCBT),and layered graph (LG) are proposed and used to construct the shared tree for multicast requests. In the CBT and LDCBT methods, a multicast tree constructing (MTC) algorithm is used to construct the multicast tree of a given multicast, and a segment-based wavelength assignment (SBWA) algorithm is proposed and used to determine the assigned wavelength of the multicast tree. Moreover, in the proposed GA, several crossover and mutation operators are developed and used to generate offspring. Simulation results show that the proposed GA together with LG or CBT multicast method can get better......