RT Journal Article T1 Software-driven Connectivity Orchestration for Multi-domain NFV Ecosystems A1 Nogales Dorado, Borja A1 Vidal Fernández, Iván A1 Valera Pintor, Francisco A1 Sánchez Agüero, Víctor A1 López, Diego R. AB Network Functions Virtualization (NFV) is a fundamental enabler in 5G networks, automating service deployment through softwarization and virtualization. However, challenges remain in providing network connectivity to service components, commonly referred to as Virtual Network Functions (VNFs), deployed on different domains. A usual approach to enable such connectivity is to rely on layer-3 routing from Internet service providers. However, this approach presents limitations to preserve isolation among remote VNFs, and may require undesirable network configurations. This paper proposes a novel connectivity orchestration service for multi-domain NFV ecosystems to address these limitations. The service is based on a set of interconnected software components that are deployed on every NFV domain. Connectivity is automatically provided to remote VNFs over the overlay network formed by these components using Software-Defined Network (SDN) technologies. The service has been prototyped using open-source software, being validated on a real NFV ecosystem. PB IEEE SN 0740-7459 YR 2024 FD 2024-03 LK https://hdl.handle.net/10016/39051 UL https://hdl.handle.net/10016/39051 LA eng NO This article has partially been supported by the European H2020 5GZORRO Project (grant agreement 871533), and the TRUE5G project funded by the Spanish National Research Agency (PID2019-108713RB C52/AEI/10.13039/501100011033) DS e-Archivo RD 17 jul. 2024