Least-Congested Distributed Lightpath Allocation

One of the main challenges in optical networking is the problem of Routing and Wavelength Assignment (RWA). Generally speaking, the algorithms proposed for RWA are divided into two categories: Centralized and Distributed. According to the scale, size and other preferences of a network, one of the above strategies can be selected for establishing lightpaths in the network. In small size networks where the number of requests is small, centralized approaches can be used for solving RWA. However, in large-scale networks with the heavy traffic load, distributed methods work appropriately. One of the distributed algorithms proposed recently is DLA. We use the DLA as our basic algorithm to design a new congestion-aware RWA algorithm. We consider congestion in the network as a decision point for solving RWA. Selection of the least congested path among available paths from source to destination can improve the blocking probability of the network.