Evolving Traffic Grooming in Multi-Layer Flexible-Grid Optical Networks With Software-Defined Elasticity

Recently, flexible grid and elastic-rate transponders have emerged as evolutionary technologies to satisfy the ever-increasing demand for higher spectrum efficiency and operational flexibility. In this study, we first briefly review the evolution of traffic grooming from SONET/SDH to currently-deployed WDM networks, and summarize the essence of the current traffic-grooming paradigm based on electronic circuit or packet switching and multi-layer collaboration. Then, the role of traffic grooming in flexible-grid and elastic-rate optical networks is re-examined. The impact of some new optical-layer technologies on traffic-grooming paradigm is discussed. Particularly, sliceable optical layer based on sliceable transponders and BV-ROADM is identified as a novel technology that could impact the future grooming paradigm by offloading considerable amount of traffic and part of electronic grooming function to the optical layer. We propose two novel network architectures based on sliceable optical layer and numerically compare them with the traditional packet-over-optical network architecture. It is found that packet-over-sliceable network architecture consumes the fewest transponders and at the same time achieves either the “lowest-possible” latency or least spectrum usage. Finally, traffic grooming, which involves multi-layer resource orchestration, should be controlled by software with a centralized view of the network to accommodate the dynamic requirements of applications.