The development of all-Optical Packet Switching (OPS) networks brings about new challenges in the topic of Optical Performance Monitoring (OPM). The objectives of this chapter are addressed to the proposal of new monitoring techniques capable of packet-by-packet monitoring in the optical domain to preserve packet transparency. Moreover, new optical layer functionalities such as dynamic reconfiguration and link level restoration also introduce a level of complexity that may require advanced OPM capabilities. In this chapter, an OSNR monitoring technique and its application for providing network intelligence are explained in detail. In particular, the integration of the monitoring system with the control and management planes is investigated to perform other functions such as quality of service implementation, OSNR-assisted routing, and backup route selection.
