The GN4-3 is the proposed project for the third Specific Grant Agreement under the 68-month Framework Partnership Agreement (FPA) established between the GÉANT Consortium and the European Commission in April 2015. This third phase of implementing the FPA is proposed to last 48 months and is a natural continuation of the work in GN4-2, building on the results and maintaining the overall objective of helping to raise European research to the next level, promoting scientific excellence, access and re-use of research data. GÉANT’s world-class, high-speed backbone provides seamless and secure connectivity with 42 National Research and Education Networks (NRENs), reaching over 50 million users in 10,000 institutions across Europe, and more than 100 countries worldwide through links with other regions. The core backbone is capable of multiple 100 Gbps transmission over each fibre link, and Terabit connectivity can be achieved by a single node. The safe and rapid connection of users to each other, to the increasing amounts of data generated by research, and to the high-performance computing capacity required by collaborative research form the foundation of the GÉANT partnership. GÉANT services offer convenient, fast and reliable access to European High Performance Computing facilities, cloud services for the research and education community, access to scientific data and publications and other services from the European e-infrastructure providers, whenever and wherever needed. The structure of the present proposal emphasises updating existing services in line with requirements of the user community. This complements the proposed companion project GN4-3N, an ambitious programme increasing the footprint of the backbone network at the same time as improving its capacity, resilience and flexibility with the aim of offering 100Gbps network access to many more GÉANT partners and significantly diminish the digital divide.