OPENFLOW/SDN FOR METRO/BACKBONE OPTICAL NETWORKS LEI LIU, HONGX I A NG GUO, AND TA K EH IRO T SU R I TA N I

Optical networks are typically composed of nodes such as reconfigurable optical add-drop multiplexers (ROADM), wavelength crossconnects (WXC), and photonic cross-connects (PXC). In the current commercial metro and backbone networks, these optical nodes are controlled and managed through the element management system (EMS) and the network management system (NMS) in a manual and semistatic style for lightpath provisioning, as shown in Figure 14.1. Although this approach is very reliable, the network carriers require a control plane technique for dynamic and intelligent control of wavelength paths in metro/backbone optical networks to save operational expense, reduce the processing latency, and handle the rapid increase of dynamic network traffic.