Terabit elastic optical networking (EON) is foreseen as a viable solution to extend the lifetime of anetwork exploiting the available bandwidth in previously deployed optical fibers. EON is based on bandwidth-variable transponders capable of supporting multiple bit rates and/ or modulation formats according to traffic requirements and node architectures that route arbitrary channel band-widths. Thus, EON increases the heterogeneity of the network, which may create the need for autonomie adaptive and/or cognitive techniques. In this context, the software-defined networking (SDN) paradigm emerges as an opportunity to enable such techniques thanks to the centralized view of the network by decoupling the control plane and the data plane.
This paper surveys different activities carried out at the Optical Technologies Division in Centro de Pesquisa e Desenvolvimento em Telecomunicações, Brazil. We review an optical transport SDN controller for virtual optical networks that supports two adaptive algorithms. First, the autonomie flexible transponder reconfigures the transmission modulation format according to a threshold level. Second, the adaptive global spectrum equalization reconfigures the wavelengths’ attenuation profiles applied at the optical nodes to improve the signals’ optical signal-to-noise ratio (OSNR) at reception. Finally, we report experimental results of an in-band OSNR monitor for advanced modulation formats.