Multilayer control for packet-optical networks [invited]

This paper describes a novel multilayer (ML) path computation element (PCE) architecture based on a hybrid approach. Such a method operates in all network life cycles, optimizing both the design and the operative phases. The hybrid PCE is based on combined non-realtime and real-time operation and is able to integrate control and management functions. This architecture results in a reduction of overprovisioning during network design while guaranteeing availability of traffic by using control-plane-driven dynamic recovery schemes. It introduces advanced control functionality into the network, providing an easy-to-integrate solution. To fully exploit the control plane capabilities, a new architecture of colorless, directionless, and contentionless reconfigurable optical add/ drop multiplexers and its related cost model are also presented. The solution has been assessed by simulations on the Spanish backbone network of Telefonica. The simulation analysis demonstrates the good performance of the proposed ML solution. The reduction of overprovisioning allows a capital expenditure saving of up to 46% with respect to a single-layer approach without any effect on the level of survivability of the traffic, thanks to new ML recovery schemes.