Senior Network Engineer

Company Overview: Radiant is redefining how AI infrastructure is built. We design and operate AI-native cloud platforms engineered for sovereignty, performance, and scale. Our infrastructure powers GPU-native workloads, multi-tenant control planes, and high-performance AI systems designed for the most demanding environments. We are not building a generic cloud. We are building purpose-built AI infrastructure - from powered land, to compute, to software . As we scale our platform and expand our engineering organisation, we are looking for leaders who can build strong teams, uphold high standards, and deliver reliably at pace. Job Description As a Senior Network Engineer, you’ll design, deploy, and operate the high-performance, low-latency network fabric that underpins our GPU infrastructure. You’ll play a critical role in shaping the architecture, automation, and operational standards of our network, ensuring it meets the rigorous demands of modern AI training and inference workloads. The ideal candidate is a strong advocate of engineering excellence and operational best practices. You’re customer-focused, collaborative, and equally comfortable discussing technical issues with enterprise customers, internal teams, and cross-functional stakeholders. You’ll contribute to everything from design and implementation through to L3/L4 operational support. Role Responsibilities - Network Architecture & Collaboration: Design scalable leaf-spine networks using Mellanox switches with Cumulus Linux, integrated with Juniper PTX routers and SRX firewalls. Lead 3rd party and internal provider collaboration to deploy resilient site-to-site and internet connectivity, optimise topology, and resolve complex faults. - Operations & Maintenance: Perform configuration, upgrades, and deep troubleshooting of Juniper and NVIDIA/Cumulus devices in production environments. - Software-Defined Networking (SDN): Implement programmable network designs using controller-based platforms to support automation and scalability. - Kubernetes Networking: Support networking within container platforms using CNIs such as Calico, Cilium, or Kube-OVN. Understand microservices traffic patterns and service mesh integrations. - Automation & Scripting: Develop and maintain Ansible playbooks and Python automation for configuration management, provisioning, and compliance, including working against API interfaces of network equipment. - Monitoring & Telemetry: Implement observability tools using SNMP, sFlow, and gRPC to detect and address network bottlenecks at scale. - Incident Management: Lead L3/L4 network incident response, escalation management and root cause analysis in high-pressure, 24×7 production environments. - Stakeholder & Customer Engagement: Act as a trusted technical expert, engaging directly with internal stakeholders and enterprise customers. Present solutions and troubleshoot effectively across all levels of the organisation. - Engineering Excellence: Promote and uphold best practices in configuration management, change control, documentation, and continuous improvement. Requirements - HPC/AI Networking: 3–5 years’ experience supporting high-throughput, low-latency infrastructure for GPU-based or HPC clusters. - 8–12+ years in networking, often with at least 5 years in globally distributed environments - Experience with multi-region or multi-continent backbone networks, transit/peering, and high-availability design at Internet scale - Hands-on with large-scale routing (BGP/MPLS), automation at scale, and often SDN or custom orchestration frameworks - Routing & Switching: Strong understanding of BGP, EVPN, VXLAN, and Data Centre Interconnects (DCI). - Hardware Platforms: - Cloud-Native Networking: Proficiency with Kubernetes networking and container-based infrastructure, including CNIs (e.g. Calico, Cilium). - Linux Proficiency: Confident with CLI environments, scripting, and diagnostics. - Automation & Tooling: Experience with Ansible and Python. Familiarity w