The introduction of SDN in Service Providers' networks like GEANT is a challenging task. Prototypes of new generation services have to exhibit "carrier grade" characteristics, meet the high level expectations and specialized needs of GEANT customers. In this demonstration, we present the SDN based prototype of GEANT Open service, used by GEANT customers and approved commercial partners to interconnect using Layer 2 circuits. Currently, this service is delivered through a set of Open eXchange Points leveraging on legacy solutions. The SDN based prototype has been realized on top of ONOS and leverages on hardware switches for the data plane. During the demo, which runs inside the GEANT Testbed Service, we show how operators can deploy services and manage the SDN based infrastructure.