SDN-Based IP and Layer 2 Services with an Open Networking Operating System in the GEANT Service Provider Network

The migration of service providers' wide area networks toward SDN is a challenging task. In this article, we consider the critical requirements of GEANT, the 500 Gb/s pan-European provider interconnecting 38 national research and educational networks, for a total of 50 million users. A long-term evolution path toward the softwarization of GEANT is discussed, consisting of four steps to be realized in future years, from providing SDN-based connectivity, to the so-called software defined infrastructure (SDI). As a first step, the softwarization of some basic services currently offered by GEANT is considered: GEANT IP, GEANT plus, and GEANT Open. This article reports the concrete experience in the SDN-based design and implementation of these services, which have been called L3-SDX and L2-SDX. Both use cases have been addressed with the use of the open source Open Network Operating System (ONOS (R)). The L3-SDX service has been developed on top of an existing ONOS application, called SDN-IP. SDN-IP allows interconnections between SDN and legacy networks through BGP. The L2-SDX service has been realized as a new ONOS application. Both services are currently deployed on the GEANT Testbed Service, a continental facility offering geographical virtual testbeds to the research community. The article reports the experience gained from this experimental deployment and discusses the benefits for a service provider like GEANT.