Routing and Spectrum Allocation in Elastic Optical Networks: A Tutorial

TLDR

Flexgrid technology is a promising solution for future high‑speed network design. The tutorial aims to cover key aspects of elastic optical networks, including node architectures, scalability, flexibility, experimental demonstrations, and open research challenges. It reviews the architecture, operation principles, node designs, and classifies routing and spectrum allocation methods, covering fragmentation, modulation, QoT, grooming, survivability, energy efficiency, and cost. Experimental demonstrations validate elastic optical network functionality, and the tutorial identifies remaining research challenges and open issues.

Abstract

Flexgrid technology is now considered to be a promising solution for future high-speed network design. In this context, we need a tutorial that covers the key aspects of elastic optical networks. This tutorial paper starts with a brief introduction of the elastic optical network and its unique characteristics. The paper then moves to the architecture of the elastic optical network and its operation principle. To complete the discussion of network architecture, this paper focuses on the different node architectures, and compares their performance in terms of scalability and flexibility. Thereafter, this paper reviews and classifies routing and spectrum allocation (RSA) approaches including their pros and cons. Furthermore, various aspects, namely, fragmentation, modulation, quality-of-transmission, traffic grooming, survivability, energy saving, and networking cost related to RSA, are presented. Finally, the paper explores the experimental demonstrations that have tested the functionality of the elastic optical network, and follows that with the research challenges and open issues posed by flexible networks.