OpenFlow and PCE architectures in Wavelength Switched Optical Networks

The GMPLS protocol suite, originally designed to fully operate in a distributed fashion, is currently the reference control plane for WSONs. Recently, the requirement of effective traffic engineering solutions has lead to the standardization of the PCE architecture, thus joining the distributed GMPLS control plane with a centralized network element devoted to path computation. However, the common need of network carriers to keep the network under a centralized control in strict relationship with the NMS has prevented the wide deployment of GMPLS in currently working optical networks. OpenFlow proposal has been recently designed for controlling Ethernet-based access/metro networks. However, thanks to its potential ability of configuring the flow table of generic switching nodes, the OpenFlow extension for enabling the control of WSONs is currently a hot research topic. In this work, OpenFlow is seen as a promising alternative for controlling WSONs. In particular, two OpenFlow-based solutions are considered and compared against GMPLS. The first solution comprises direct configuration of the optical nodes and extends OpenFlow protocol to improve the lightpath reservation. The second solution integrates OpenFlow with GMPLS protocols exploiting communication between the OpenFlow controller and the GMPLS controller of optical nodes. Simulations results show the ability of the OpenFlow-based solutions to enable traffic engineering while providing fast lightpath setup and assuring control plane scalability.