波分复用光网络动态共享通道保护方法的研究

ON THE APPROACH FOR DYNAMIC SHARED-PATH PROTECTION OF WDM-BASED OPTICAL NETWORKS

利用分层图模型来记录网络波长使用状态,并提出了链路状态描述模型。给出了动态工作和保护通道分配算法,先在所有波长层中寻找一条工作代价最小的路径作为工作通道,然后在该波长层寻找保护代价最小的路径作为保护通道。对类Cernet和5×5Mesh_Torus两种网络拓扑进行了仿真。模拟结果表明,随着网络负载的增加,阻塞率增加;随着光纤波长数的增加,阻塞率减少。在相同的网络负载和波长数时,类Cernet拓扑的阻塞率高于5×5Mesh_Torus拓扑。当网络处于重载状态,增加波长数可以显著降低阻塞率;而网络处于轻载状态,增加波长数基本不改变网络阻塞率。

The layered-graph model was applied to record the usage state of wavelength in network, and a link state description model was presented. A working and protection path dynamic assignment algorithm was introduced and tested in Cernet topology and 5 × 5 Mesh Torus topology. The working path was determined first as a path with minimum working cost chosen from all wavelength layers, then the protection path was selected as a path with minimum protection cost chosen from the same layer. The simulation result showed that the block probability increases as the network offered load grows while the block probability decreases as the optical wavelength number rises. When the load and wavelength number are the same, the block probability is higher in Cernet network than in 5 × 5 Mesh_Torus network. When the load of net- work is high, the growth of wavelength number can reduce the block probability significantly. The block probability almost does not change with the increase of wavelength number under the condition of light load.