Senior Network Engineer

About Nebius: Nebius is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. *]:pointer-events-auto scroll-mt-[calc(var(--header-height)+min(200px,max(70px,20svh)))]" data-turn-id="request-WEB:15eea77a-430d-424c-853f-ddcbc7d37ef3-17" data-testid="conversation-turn-8" data-scroll-anchor="true" data-turn="assistant"> The role: We are looking for a Senior Network Engineer to design, build, and operate large-scale, high-performance data center networks supporting GPU-dense AI workloads. You will take end-to-end ownership of service provider–grade and CLOS-based network infrastructure, ensuring reliability, scalability, and predictable performance across distributed environments. This role requires deep expertise in routing, switching, and modern data center fabrics, with a strong focus on production operations, root cause analysis, and continuous improvement of network systems. Your responsibilities will include: • Design and evolve scalable data center network architectures (CLOS/leaf-spine) for high-throughput, low-latency environments • Own end-to-end deployment and lifecycle management of routing and switching infrastructure across production environments • Develop and maintain network design documentation, standards, and operational procedures • Plan, execute, and validate network infrastructure testing, including vendor evaluation and benchmarking • Diagnose and resolve complex network issues across the TCP/IPv4/v6 stack in large-scale distributed environments • Optimize traffic engineering, ECMP, and load balancing strategies to ensure efficient utilization of network resources • Implement and operate MPLS-based technologies, including L3 VPNs and segment routing (SR-MPLS, SRv6) • Collaborate with hardware, systems, and software teams to integrate networking with compute and storage infrastructure • Automate network operations and workflows to improve reliability, scalability, and operational efficiency • Ensure high availability and performance of production networks through proactive monitoring and continuous improvement What we expect you to have: • Expert-level knowledge (CCIE/JNCIE or equivalent) in MPLS, routing, and switching for service provider and data center networks • Strong experience with Ethernet switching, VXLAN, and modern cloud overlay networking technologies • Deep expertise in routing protocols including BGP and IS-IS • Hands-on experience with segment routing (SR-MPLS, SRv6), L3 MPLS VPNs, and ECMP-based traffic balancing • Proven experience designing and documenting large-scale network architectures • Experience developing and executing network testing strategies and validating vendor solutions • Strong troubleshooting skills across the TCP/IPv4/v6 stack in CLOS-based data center environments • Solid understanding of network hardware architecture, QoS mechanisms, and packet processing pipelines • Hands-on experience with network equipment from vendors such as Juniper, Arista, Huawei, and Mellanox • Working proficiency in English It will be an added bonus if you have: • Working proficiency in an additional European