LC-DLA: A fair congestion-aware Distributed Lightpath Allocation mechanism

One of the main challenges in all-optical WDM networks is the problem of Routing and Wavelength Assignment (RWA). In large-scale networks with heavy traffic load, distributed RWA is more suitable than centralized RWA. One of the distributed algorithms proposed recently is Distributed Lightpath Allocation (DLA) [1]. We use the DLA as our basic algorithm to design a new congestion-aware RWA algorithm, called Least-Congested Distributed Lightpath Allocation (LC-DLA). 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. Fairness is one of the crucial metrics that network designers should consider. We define a new concept for fairness in RWA. Our performance evaluations show that LC-DLA can provide good blocking and fairness performances in WDM networks.