Senior Network Architect - Cisco (SC Cleared)

Salary: £70,000 - 110,000 per year

Requirements:

• Strong enterprise network architecture experience, including assessing existing implementations and producing accurate High Level Designs and Low Level Designs.
• Hands-on Cisco ACI experience, including fabric architecture, tenants, VRFs, bridge domains, endpoint groups and contracts, with an understanding of application-centric policy design.
• Strong Cisco routing knowledge and practical understanding of IP addressing, routing protocols, segmentation and connectivity between data centres.
• Experience reviewing Cisco ASA firewall configurations, traffic flows, access policies, NAT and high-availability arrangements.
• Experience with F5 load balancers, including traffic management, health monitoring, resilience and dependencies on surrounding network services.
• Experience assessing network disaster recovery and active/active designs, including failure scenarios, failover behaviour, routing symmetry and stateful service dependencies.
• Ability to investigate live configurations safely, identify technical constraints and recommend proportionate changes with clear implementation and operational impacts.
• Strong technical writing, diagramming and stakeholder communication skills, with experience taking designs through formal review and approval.
• Desirable: Cisco ACI deployments spanning multiple data centres and migration towards application-centric policies.
• Desirable: Network resilience testing, recovery planning and assessment of hardware, software and licensing options.
• Desirable: Experience in defence, government or other regulated environments with controlled technical data and formal configuration management.
• Desirable: Relevant Cisco, F5 or network architecture certifications, such as CCNP or CCIE.
• A minimum of UK SC clearance.

Responsibilities:

• Review the live network implementation, configurations and legacy design material across both data centres, identifying gaps between documented and actual operation.
• Produce accurate current-state High Level Designs and Low Level Designs using company templates, with topology diagrams, connectivity flows and technical dependencies.
• Review Cisco ACI, routing, firewall and load-balancing arrangements with Architecture and Network support teams to understand service connectivity and operational constraints.
• Produce a Network Review and Recommendation Report identifying practical improvements that can be made without significant redesign and with minimal risk to live services.
• Assess opportunities to make better use of Cisco ACI application-centric capabilities, including application relationships, segmentation and policy design.
• Present recommended improvements as a prioritised roadmap showing sequencing, interdependencies, implementation considerations and service impact.
• Produce a Network Disaster Recovery Capability Report assessing the changes required for true active/active connectivity between the two data centres.
• Explain current connectivity limitations, proposed implementation approaches, risks to existing services and any additional hardware, software or licensing requirements.
• Lead technical review discussions, resolve design comments and secure review and sign-off of design documentation from Architecture and Network teams.
• Maintain controlled technical documentation and supporting evidence, contribute to risk and issue reporting, and submit deliverables through agreed secure channels.

Technologies:

• Architect
• Cisco
• Fabric
• Firewall
• Hardware
• Support
• NAT
• Network

More:

We are seeking a Senior Network Architect for an initial assignment supporting our bridging the Gap programme and its Network team. The secure defence environment includes two data centres with Cisco ACI, Cisco routers, Cisco ASA firewalls and F5 load balancers. You will work alongside our Architecture and Network support teams to document and improve the existing network, with a focus on operational resilience. The role is full-time, based in Bristol with no remote working, and offers a salary of £70,000–£80,000.

• opportunities to develop your skills
• meaningful project work
• supportive leadership and a collaborative environment
• training and development resources
• a 24/7 confidential employee assistance programme
• social events
• 25 days of annual leave with the option to purchase additional leave
• a pension salary exchange scheme
• life assurance
• private medical insurance
• worldwide travel insurance

last updated 40 week of 2026

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