HPC Network Engineer

Salary: £63,000 - 103,000 per year

Requirements:

• 5+ years as a network engineer operating production data centre networks
• Strong dynamic routing experience, particularly BGP, plus overlay/encapsulation design and troubleshooting such as EVPN/VXLAN
• Hands-on experience with leaf-spine / Clos fabric design and operation
• Experience with modern data centre network operating systems and comfort with the Linux networking stack, not just a vendor CLI
• Practical RDMA fabric experience, such as lossless Ethernet with RoCEv2 and PFC/ECN/DCQCN tuning, or InfiniBand, with an understanding of why lossless behaviour matters for GPU workloads
• Network automation as a working practice, including scripting such as Python, configuration management such as Ansible, config generation from a source of truth, and version-controlled changes
• Solid Linux administration fundamentals, with the ability to debug from the host side as well as the switch side
• Experience with network telemetry and monitoring, such as Prometheus/Grafana, sFlow/IPFIX, or streaming telemetry
• Experience running corporate/campus networks, including wired and wireless, switching, NAC/802.1X, VPN, and remote access
• Clear communicator who enjoys teaching and can document, pair, and run sessions that bring less network-savvy colleagues up to speed
• Relevant certifications such as CCNP/CCIE or equivalent are valued as evidence of depth, not a gate

Responsibilities:

• Design and operate lossless, RDMA-capable fabrics for GPU compute and storage traffic, including QoS, congestion control, and buffer tuning at scale
• Build and manage leaf-spine data centre fabrics, with routed underlay and overlay design
• Implement and maintain per-tenant network isolation across compute, storage, and management planes
• Automate network provisioning, configuration, and validation, treating switch config as code and deploying through CI
• Build telemetry and observability for the fabric, including dashboards and alerting that catches congestion and link degradation early
• Troubleshoot performance issues end to end, from optics and cabling through switch buffers to NIC/DPU configuration and collective-communication behaviour on the hosts
• Operate the out-of-band management network, console access, and remote recovery paths
• Support tenant onboarding, including segmentation and addressing, bandwidth and isolation guarantees, and capacity planning as the cluster scales
• Write clear design documentation capturing decisions, rationale, and rejected alternatives
• Own and maintain the office network, including wired and wireless infrastructure, firewalling, VPN/remote access, and connectivity between the office and data centre environments
• Upskill colleagues on networking through documentation, run-throughs, and pairing so the wider team can operate and troubleshoot the fabric confidently

Technologies:

• AI
• Ansible
• Ethernet
• Fabric
• Grafana
• InfiniBand
• Support
• LESS
• Linux
• Network
• Prometheus
• Python
• RDMA
• VPN
• Bootstrap
• Cisco
• Datadog
• Firewall
• FortiGate
• Flow
• NodeJS

More:

We are Fuse Energy, a forward-thinking renewable energy startup on a mission to deliver a terawatt of renewable energy fast. We combine first-principles thinking with cutting-edge technology to build a radically better energy system. We have raised $210M from top-tier investors including Multicoin, Balderton, Lakestar, Accel, Creandum, Lowercarbon, Ribbit, Box Group, and strategic angels such as Nico Rosberg, the Co-Founder of Solana, and GPs behind Meta, Revolut, Spotify, Uber, and more. This is a full-time role focused on designing, deploying, and operating the network fabric for our multi-tenant AI cluster, plus owning the office network and acting as the networking authority for the company. We offer a competitive salary, an equity sign-on bonus, a biannual bonus scheme, fully expensed tech to match your needs, and breakfast and dinner allowance for office-based employees.