Software-defined optical networks and network abstraction with functional service design [invited]

The combination of software-defined networking (SDN) and optics, i.e., a software-defined optical network (SDON), offers combined benefits that include flexible SDN control and large optical transport capacity. In this paper, we introduce the unified SDN as a common control solution for end-to-end OCS/OPS networks, with the introduction of an additional network element, namely the OpenFlow agent. The SDN control plane is implemented in the OPS network for simplified data plane design, optimal network organization, and contention alleviation, as well as improved control flexibility and advanced handling of network dynamics. The SDON demonstration is conducted in the nationwide transport networks constructed with different technologies via various internetworking testbeds. Based on the SDON platform, we further introduce the service design concept for advanced network abstraction. The general network architecture based on a service design concept offering flexible, reconfigurable, and economical end-to-end (FREE) service features is described. This service design aims to provide customized service and maximum network freedom with virtualized and flexibly selected functionalities, while maintaining a moderate network configuration cost and promoting network innovation at the same time. Moreover, the service design concept could easily be extended to any layers and any network domains, thus providing the unified network abstraction ability and the end-to-end control solution. Based on the service design, control, coordinated, and orchestrated optical transmission is demonstrated by reconfiguring the virtualized optical functions. This type of approach to network abstraction is further exploited in the heterogeneous multidomain networks, where differentiated and featured service provisioning is demonstrated.