Network Architect (DV Security Clearance)

As a Network Architect, you will define and assure secure, resilient network architectures across physical, virtual and software-defined infrastructure, with a strong focus on VMware NSX-T/NSX and network virtualisation.

You will design NSX networking solutions covering logical switching and routing, overlay/underlay integration, Tier-0/Tier-1 gateways, Edge services, segmentation, micro-segmentation and distributed firewalling. You will ensure effective integration between NSX, physical networks, VMware infrastructure and Kubernetes/VKS platforms. Working across infrastructure, security and engineering teams, you will provide technical leadership throughout design, build and integration, ensuring solutions meet performance, availability, resilience and security requirements.

Key responsibilities:

• Design end-to-end physical, virtual and software-defined network architectures.

• Define VMware NSX-T/NSX architecture, including segments, overlays, Tier-0/Tier-1 gateways and Edge services.

• Design routing, switching, firewalling, VPN and secure connectivity solutions.

• Define segmentation and micro-segmentation using NSX Distributed Firewall (DFW).

• Integrate NSX with physical infrastructure, VMware and Kubernetes/VKS environments.

• Define resilient network architectures, redundancy and failover.

• Resolve complex routing, traffic-flow, latency, capacity and performance challenges.

• Embed security-by-design and zero-trust principles.

• Produce HLDs, LLDs, network diagrams and technical design documentation.

• Provide technical assurance through architecture and design reviews.

You will have strong network architecture experience within complex infrastructure environments, ideally within Defence or National Security, with particular expertise in VMware NSX-T/NSX and virtual networking.

Essential experience:

• Strong VMware NSX-T/NSX architecture and design experience.

• Strong understanding of software-defined networking and network virtualisation.

• Experience with NSX logical switching/routing, Tier-0/Tier-1 gateways and Edge architectures.

• Experience with NSX DFW, segmentation and micro-segmentation.

• Strong understanding of overlay/underlay networking and physical/virtual network integration.

• Strong knowledge of TCP/IP, VLANs, BGP, VPNs and routing technologies.

• Network security architecture, including firewalls, zero trust and encrypted connectivity.

• Kubernetes networking experience, ideally including VKS.

• High availability, resilience, redundancy and failover design.

• Ability to produce high-quality HLDs, LLDs and architecture diagrams.

• Strong technical leadership and stakeholder communication skills.

Desirable

• NSX Federation and multi-site architecture.

• VMware Cloud Foundation (VCF).

• EVPN/VXLAN.

• Kubernetes CNI and network policy.

• Infrastructure as Code using Terraform or Ansible.

• NSX/API-based network automation.

• Network monitoring and observability.

• SD-WAN and load-balancing technologies.

• Relevant VMware, networking or security certifications.

Together, as owners, let’s turn meaningful insights into action.

CGI was recognised in the Sunday Times Best Places to Work List 2025 and has been named a UK ‘Best Employer’ by the Financial Times. We offer a competitive salary, excellent pension, private healthcare and a share scheme (3.5% + 3.5% matching), making you a CGI Partner rather than simply an employee.

This role is based on-site near Chippenham, five days per week. Due to the secure nature of the programme, you must hold UK Security Clearance.

CGI’s Space, Defence and Intelligence business unit designs, builds and operates secure, mission-critical systems across defence, intelligence, aerospace, maritime and space. We combine deep technical expertise with leading technology partners to deliver complex infrastructure and cyber solutions., Life at CGI is rooted in ownership, teamwork, respect and belonging. Here, you’ll reach your full potential because

You are invited to be an owner from day 1 as we work together to bring our Dream to life. That’s why we call ourselves CGI Partners rather than employees. We benefit from our collective success and actively shape our company’s strategy and direction.

Your work creates value. You’ll develop innovative solutions and build relationships with teammates and clients while accessing global capabilities to scale your ideas, embrace new opportunities, and benefit from expansive industry and technology expertise.

You’ll shape your career by joining a company built to grow and last. You’ll be supported by leaders who care about your health and well-being and provide you with opportunities to deepen your skills and broaden your horizons.

That same commitment to fairness extends to how we use technology. To support our recruitment team, AI tools may be used to help assess applications though they never replace human judgement. All hiring decisions remain entirely in the hands of our recruitment professionals.

Come join our team-one of the largest IT and business consulting services firms in the world.