Senior Network Engineer

Senior Network Engineer - InfiniBand / UFMNew York, New York, United States; San Francisco, California, United States; Seattle, Washington, United StatesWho We AreLightning AI is the company behind PyTorch Lightning. Founded in 2019, we build an end-to-end platform for developing, training, and deploying AI systems—designed to take ideas from research to production with less friction.Through our merger with Voltage Park, a neocloud and AI Factory, Lightning AI combines developer-first software with cost-efficient, large-scale compute. Teams get the tools they need for experimentation, training, and production inference, with security, observability, and control built in.We serve solo researchers, startups, and large enterprises. Lightning AI operates globally with offices in New York City, San Francisco, Seattle, and London, and is backed by Coatue, Index Ventures, Bain Capital Ventures, and Firstminute.The RoleWe are seeking an experienced Senior Network Engineer (InfiniBand / UFM) to design, deploy, automate, and operate next-generation AI Factory networking infrastructure supporting large-scale GPU clusters. This role is responsible for building and maintaining high-performance NVIDIA Quantum InfiniBand fabrics that power AI training and inference environments utilizing NVIDIA UFM, NCCL, RoCEv2, and modern data center technologies.The ideal candidate has deep expertise in InfiniBand networking, NVIDIA Unified Fabric Manager (UFM), large-scale GPU deployments, Linux networking, automation, and troubleshooting distributed AI workloads.What You'll DoDesign, deploy, and maintain large-scale NVIDIA InfiniBand fabrics supporting AI/ML GPU clusters.Deploy and administer NVIDIA Unified Fabric Manager (UFM) Enterprise for monitoring, provisioning, telemetry, and fabric health.Configure and optimize NVIDIA Quantum and Quantum-2 InfiniBand switches.Troubleshoot fabric performance issues impacting NCCL, MPI, GPUDirect RDMA, and AI training jobs.Implement and validate fat-tree, Dragonfly+, Clos, and spine-leaf network architectures.Perform firmware lifecycle management for InfiniBand switches, adapters (HCAs), and UFM infrastructure.Optimize congestion control, adaptive routing, QoS, and traffic engineering for high-performance GPU communication.Work closely with AI platform, GPU infrastructure, storage, and systems engineering teams to deploy scalable AI Factory environments.Automate network provisioning using Python, Ansible, Git, REST APIs, and Infrastructure-as-Code methodologies.Monitor network health using UFM telemetry, Prometheus, Grafana, and other observability platforms.Support high availability, maintenance windows, incident response, root cause analysis, and capacity planning.Participate in architecture reviews and define networking standards for AI infrastructure.Required Qualifications7+ years of data center networking experience.3+ years supporting NVIDIA InfiniBand environments.Hands-on experience with NVIDIA UFM Enterprise.Experience deploying and operating Quantum and Quantum-2 InfiniBand switches.Strong understanding of: InfiniBand Architecture, Subnet Manager (SM), Adaptive Routing, Congestion Control, Partition Keys (PKeys), LIDs, Queue Pairs (QP), Virtual Lanes (VL), Service Levels (SL)Strong Linux administration experience (Ubuntu).Experience with automation using Python and Ansible.Deep understanding of Layer 2 and Layer 3 networking.Experience with BGP, EVPN, VXLAN, and modern spine-leaf architectures.Experience with packet captures and troubleshooting using tcpdump, Wireshark, and ibdiagnet tools.Excellent troubleshooting and communication skills.What You Bring10+ years of experience in large-scale data center networkingDeep expertise in spine-leaf architectures and L3 fabricsStrong experience with BGP, EVPN, VXLANExperience operating high-performance computing (HPC) or GPU-dense environmentsExperience designing networks for hyperscalers, neoclouds, or high-scale SaaS infrastructureStrong automation background (Python, Ansible, Terraform, or similar)Experience with network observability tooling and telemetry pipelines Proven ability to design systems that scale to thousands of nodesStrong documentation and architectural communication skillsNice to HaveExperience with Netris and Terraform.Experience with multi-region backbone designExposure to bare-metal provisioning systemsExperience working in high-growth infrastructure startupsWhy This Role MattersThe network is the foundation of distributed AI training. Performance bottlenecks at the fabric layer directly impact customer workloads.This role will shape how Voltage Park scales from tens of thousands of GPUs to significantly beyond — ensuring deterministic performance, predictable scaling, and enterprise-grade reliability.If you want to architect infrastructure that powers frontier AI research, this is the role.We are committed to offering competitive compensation that reflects the value each team member brings to our mission. Final offers are based on factors such as experience, skills, geographic location, and role expectations. In addition to base salary, our total rewards package for eligible roles includes a discretionary bonus, a meaningful equity component, and comprehensive benefits.The anticipated annual base salary range for this role is:$170,000 - $210,000 USDBenefits and PerksWe offer a comprehensive and competitive benefits package designed to support our employees' health, well-being, and long-term success. Benefits may vary by location, team, and role.Benefits include:Comprehensive medical, dental and vision coverage (U.S.); Private medical and dental insurance (U.K.)Retirement and financial wellness support (U.S.); Pension contribution (U.K.)Generous paid time off, plus holidaysPaid parental leaveProfessional development supportWellness and work-from-home stipendsFlexible work environmentAt Lightning AI, we are committed to fostering an inclusive and diverse workplace. We believe that diverse teams drive innovation and create better products. We provide equal employment opportunities to all employees and applicants without regard to race, color, religion, gender, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other protected characteristic. We are dedicated to building a culture where everyone can thrive and contribute to their fullest potential.