Dimensioning and energy efficiency of multi-rate metro rings

Due to the ever-growing network capacity demand, energy-efficient and scalable networking solutions are needed in all networking segments. This paper focuses on the metro segment and compares the power consumption for three different technologies: Ethernet, Reconfigurable Optical Add-Drop Multiplexers (ROADM), and an optical packet switching (OPS) solution called Packet Optical Add-Drop Multiplexers ("POADM"), which was recently proposed. A novel resource allocation strategy for POADMbased OPS multi-rate rings is proposed for the first time. The multi-rate POADM ring network resource allocation problem is shown to be NP-hard and solved using both an MILP formulation and a heuristic. The MILP formulation and the heuristic are compared, along with dimensioning results for Ethernet and ROADM ring networks. Results show that multi-rate POADM rings achieve savings up to 10% with respect to single-rate design and can be enabled by assigning a different rate to each wavelength. Furthermore, POADM rings can be up to 5 times more energyefficient than Ethernet rings and 30% than ROADM rings.