Network Engineers (DV Security Clearance) (IT)

CGI?s Space, Defence and Intelligence business unit delivers innovative, secure, and mission-critical technology solutions to some of the UK government?s most complex challenges. Our teams design, build, operate, and modernise large-scale infrastructure estates, working in close partnership with our clients to ensure resilience, performance, and security. We are seeking a Senior Network Engineer to provide hands-on technical expertise across network design, automation, operations, and modernisation initiatives. You will play a key role in sustaining and evolving complex networking environments, including legacy infrastructure, while contributing to the delivery of next-generation hybrid and multi-cloud network architectures. This role suits an experienced, self-motivated engineer with strong networking fundamentals, a passion for automation, and the ability to operate effectively in highly secure environments. Due to the nature of the work, this role is open only to sole UK Nationals who hold or are eligible for DV / HLC clearance, and requires full onsite attendance. Candidate profile: Network Design & Architecture

• Design and implement scalable, resilient LAN, WAN, and data centre network architectures.
• Design and deploy next-generation hybrid and multi-cloud WAN solutions using physical and virtual appliances.
• Implement application and network policies within Cisco SD-WAN environments.

Network Operations & Support

• Maintain and support legacy and end-of-life network infrastructure, ensuring high availability, reliability, and performance.
• Diagnose and resolve complex issues across LAN, WAN, VPN, and data centre environments.
• Participate in incident, problem, and capacity management processes.

Automation & Infrastructure as Code

• Develop and implement network automation solutions using scripting languages such as Python.
• Automate configuration, deployment, and operational tasks, including event-driven automation.
• Contribute to network automation initiatives alongside DevOps and development teams.

High Availability & Load Balancing

• Design, implement, and validate high-availability network solutions.
• Configure and manage load balancing technologies to ensure optimal traffic distribution.
• Perform testing and validation to ensure network resilience and failover effectiveness.

Monitoring, Change & Modernisation

• Monitor network traffic and performance, identifying and resolving bottlenecks.
• Implement network changes, upgrades, and patching through controlled change management processes.
• Support network modernisation and migration initiatives to contemporary platforms and cloud services.

Collaboration & Documentation

• Work closely with infrastructure, service management, security, and application teams.
• Produce and maintain clear network documentation, including designs, configurations, and procedures.
• Provide guidance and mentoring to junior engineers where required.

Required qualifications to be successful in this role Strong experience in network engineering and architecture, including LAN, WAN, and data centre environments. Hands-on experience with Cisco networking technologies, including Cisco SD-WAN. Solid understanding of IP networking, routing and switching protocols.

• Experience with multicast network flows, load balancing, and high-availability solutions.
• Proven experience supporting business-critical network infrastructure in secure environments.
• Strong troubleshooting and operational support skills.
• Experience working within structured delivery frameworks (e.g. backlog-driven delivery, PI planning, change control).

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