We are seeking a Senior Network Architect to assess, document and improve enterprise network architecture in a secure defence environment. You will combine detailed technical investigation with clear design documentation and practical recommendations for operational resilience. 

Your initial assignment will support bridging the Gap programme and its Network team. The estate spans two data centres and includes Cisco ACI, Cisco routers, Cisco ASA firewalls and F5 load balancers.

Working alongside Architecture and Network support teams, you will establish an accurate view of the existing network, recommend improvements with minimal operational risk and assess the changes needed to support true active/active connectivity between the two data centres. 

Salary: between £70,000 to £80,000

Location: Bristol (no remote working)

Clearance: a minimum of UK SC clearance

What you will do: 

• 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, supported by clear topology diagrams, connectivity flows and technical dependencies. 

• Review Cisco ACI, routing, firewall and load-balancing arrangements with the 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.

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 experience 

• Cisco ACI deployments spanning multiple data centres and migration towards application-centric policies. 

• Network resilience testing, recovery planning and assessment of hardware, software and licensing options. 

• Defence, government or other regulated environments with controlled technical data and formal configuration management. 

• Relevant Cisco, F5 or network architecture certifications, such as CCNP or CCIE. 

Benefits

By joining us you can expect

• Autonomy to develop and grow your skills and experience
• Be part of exciting project work that is making a difference in society
• Strong, inspiring and thought-provoking leadership
• A supportive and collaborative environment

As well as this, we offer:

• Development access to LinkedIn Learning, a management development programme and training
• Wellness 24/7 Confidential employee assistance programme
• Social - Breakfast Tuesdays, Thirsty Thursdays and Pizza on the last Thursday of each month as well as commitment to charitable causes
• Time off 25 days a year; plus the opportunity to purchase extra leave per year
• Pension Salary Exchange Scheme with 4% employer contribution and 5% employee contribution
• Life Assurance of 4 times base salary
• Private Medical Insurance which is non-contributory (spouse and dependants included)
• Worldwide Travel Insurance which is non-contributory (spouse and dependants included)