Energy-efficient Protection with Directed p-Cycles for Asymmetric Traffic in Elastic Optical Networks

This paper studies energy-efficient protection for asymmetric traffic in Elastic Optical Networks (EONs). Directed pre-configured Cycles (p-Cycles) are designed to protect directional traffic with flexible spectrum allocation and adaptive modulation formats. A Mixed Integer Linear Programming (MILP) model is formulated to minimize total energy consumption while generating directed p-cycles without candidate cycle enumeration. To enable the scalability, the MILP model is decomposed into a Promising Energy-efficient p- Cycle Selection (PECS) algorithm and a simplified Integer Linear Programming (ILP) model. Simulation results show that the proposed energy-efficient directed p-cycles achieve significant energy savings for asymmetric traffic protection compared with energy-efficient undirected p-cycles (up to 47.9 %) and non-energy-efficient diprected p-cycles (up to 35.7 %).