An Optimal Design Framework for 1 + 1 Routing and Network Coding Assignment Problem in WDM Optical Networks

Network coding (NC) features a new perspective for leveraging network performances as more efficient resources utilization could be achieved. In recent years, the application of NC to the realms of failure recovery in optical networks has been receiving growing attention and indeed, combining the near-instantaneous recovery of dedicated protection and improved capacity efficiency enabled by NC constitutes an important research trend in optical protection. In order to maximize the benefits empowered by NC, a critical problem on routing of traffic demands, selecting demands for encoding and determining the respective coding node and coding links has to be optimally addressed. The problem becomes even more challenging if multiple traffic demands are considered at once and the traffic is non-equal. In addressing those issues, for the first time, we present a novel unified framework for augmenting 1 + 1 dedicated protection against single link failures with a practical network coding scheme based on XOR operation for both equal and non-equal traffic scenarios. In line with this framework, a mathematical model in the form of integer linear programming for optimal routing and network coding assignment to minimize the path cost is presented. Numerical results based on evaluating the model on realistic topologies and all-to-one traffic setting highlight the cost advantages of our proposed NC-assisted protection scheme compared to traditional counterparts.