考虑链路负载均衡和容量限制的WDM光传送网保护设计

Protection Design for WDM Transport Networks Considering Load Balance of Links and the Constraint of Link Capacity

网络的生存性是WDM光传送网设计时必须考虑的问题 .在叠加 (Overlay)模式的网络构架中 ,由于光路之间存在的依赖性 ,物理网络的单链路失效可能会造成虚拓扑不连通而使上层网络 (SDH、ATM或IP)无法使用自身的恢复机制来恢复受影响的业务 ,因此虚拓扑在嵌入物理拓扑时必须避免发生这种情况 .本文提出的VTMPD算法就是针对这一问题的保护设计算法 .此算法同时考虑了物理链路的负载均衡和容量限制 .我们还给出了VTMPD算法和已有的DAP算法的性能对比 。

Network survivability is an important problem for WDM (Wavelength division multiplexing) transport network design. In network architecture using overlay mode, internal dependence of lightpaths could lead to the critical status that the failure of a physical fiber leaves the virtual topology unconnected. This may make the restoration of service impossible by the higher level networks using the WDM network such as SDH (Synchronous digital hierarchy), ATM (Asynchronous transfer mode) or IP. It is necessary to avoid the above cases while embedding virtual topology into physical topology. VTMPD (Virtual topology mapping for protection design) algorithm proposed in this paper aims at design protection, considering load balance and capacity constraint of physical links simultaneously. We also compare the performance of VTMPD with the existent DAP (Disjoint alternate path) algorithm. The numerical results show that VTMPD algorithm is better than DAP algorithm.