波分复用光网络中考虑端口连通性限制的动态路由机制

Inner-Port Connectivity Aware Dynamic Routing Schemes in Optical Wavelength Division Multiplex Networks

随着光网络规模的不断扩大,多维度可重构光分插复用器(ROADM)已成为下一代通信网络的关键节点技术。然而由于无阻塞的高维度交换矩阵的实现代价高,不对称的交换架构(即光节点内部存在不连通的端口)可能被广泛应用。为解决考虑端口连通性限制的路由与波长分配问题,建立了其整数线性规划(ILP)模型,并提出了3种考虑端口连通性(IPCA)的动态路由机制,包括基于K最短路(KSP)的IPCA(IPCA-KSP)机制、IPCA-Dijkstra机制与全路径搜索机制。仿真显示,全路径搜索机制采用枚举的方法可找到最短路径,但其阶乘量级的复杂度是无法容忍的。基于IPCA-SKP机制不能保证找到最短路径,且仅在小规模网络比较有效。而IPCA-Dijkstra机制通过修正经典Dijkstra算法的路径搜索过程,能够以较低的复杂度找到最短路径。

As the scales of the optical networks grows continuously, the multi-dimensional reconfigurable optical add- drop multiplexer （ROADM） becomes the key node technology in the next generation communication networks. However, because of the high cost of the non-blocking high-degree optical switching fabric, the asymmetric switching fabric （i. e. there are unconnected ports in an optical node） can be widely used. To solve the inner-port connectivity aware （IPCA） routing and wavelength allocation problem, an integer linear programming （ILP） model is first formulated. Then three IPCA routing schemes are proposed, including the IPCA based on K-shortest pathe （IPCA- KSP） scheme, the IPCA-Dijkstra scheme and entire path searching （EPS） scheme. Simulation results show that, the EPS scheme can find the shortest path by enumeration, but its factorial computational complexity is not tolerable. The IPCA-KSP scheme cannot guarantee to find the shortest path, which only works effectively in small-scale networks. By modifying the path search process of the classical Dijkstra＇s algorithm, the IPCA-Dijkstra scheme can find the shortest path with low complexity.