Single-Hop-First Routing and Dynamic Rerouting for Greener OTN over EON

Multi-Hop routing in multilayer Ethernet-Over-Optical Transport Network (OTN) and Elastic Optical Network (EON) architectures can lead to increased latency and cost as well as power consumption. To address these challenges, we propose a two-phase routing strategy that separates the search for single-hop and multi-hop paths. Additionally, we introduce a dynamic rerouting mechanism that assigns temporary multi-hop paths to incoming demands and later redirects them to optimized single-hop paths as resources become available. By periodically evaluating the feasibility of establishing direct lightpaths, the proposed approach minimizes energy usage while enhancing overall network efficiency. Simulation results demonstrate that our rerouting technique significantly reduces OTN switching and power consumption while improving the probability of blocking demands and resource utilization compared to traditional multi-hop routing methods.