This paper presents an improved distributed ant colony optimisation algorithm for routing and spectrum assignment (RSA) on optical burst switched (OBS), flexible spectrum networks, with the spectrum continuity constraint imposed. The improved algorithm incorporates a distributed method for monitoring the congestion along the links and using this information to determine what route-spectrum combination should be selected to minimise the burst loss probability (BLP). Evaluations were performed on an optical burst switching simulator to determine the effect on BLP when a dynamic route congestion measure is considered as opposed to the use of the static route length measure. The evaluations, considering the effects of optical impairments, were made on different network topologies, with multiple spectrum widths provisioned on the network, and with different loads. The incorporation of congestion measures into the algorithm showed improvements in BLP over previous work in the range of 2–32% depending on the evaluation conditions.

本文提出了一种改进的分布式蚁群优化算法，用于光突发交换 (OBS)、灵活频谱网络上的路由和频谱分配 (RSA)，并施加了频谱连续性约束。改进后的算法结合了一种分布式方法，用于监测链路沿线的拥塞情况，并使用此信息来确定应选择哪种路由-频谱组合，以最大限度地减少突发丢失概率 (BLP)。在光突发交换模拟器上进行了评估，以确定在考虑动态路由拥塞测量而不是使用静态路由长度测量时对 BLP 的影响。考虑到光学损伤的影响，评估是在不同的网络拓扑上进行的，网络上提供了多个频谱宽度，和不同的负载。根据评估条件，将拥塞措施纳入算法显示 BLP 比以前的工作有 2-32% 的改进。