This paper gives an overview on how Software Defined Networking (SDN) principles can be applied to existing optical networks, considering the requirements introduced by the last technology's improvement. A description of a proof of concept activity will be proposed. The demonstration shows how extending SDN to the metro area and wide area network (Transport SDN) can fully exploit the dynamism of an Agile Optical Network, with multi-tenant service management, virtual slicing of network resources for advanced services such as Encrypted and Secure Data Center connection, or Dynamic Bandwidth Allocation and even GMPLS restoration that are under Transport SDN control.