Routed Optical Networking: an alternative architecture for IP+Optical aggregation networks

For many years the best strategy to optimize the Total Cost of Ownership (TCO) of an IP+Optical network has been to reduce as much as possible the utilization of IP routers’ switch fabrics and interfaces. This can be achieved by means of optical bypass using Reconfigurable Add/Drop Multiplexers (ROADMs). This strategy comes at the cost of a suboptimal wavelength utilization and longer (on average) optical links, running with a lower OSNR. In this paper we analyse alternative architectures which take advantage of the latest Network Processing Units (NPUs) in IP routers and pluggable 400G DWDM interfaces, which helps reducing the cost associated to packet processing.