Network Architect (Data Centre) – SC Cleared at Ferns IT Consultancy Ltd, Bristol, £2,150 - £3,500 a month

Location: Bristol / Milton Keynes – Hybrid
Contract: Outside IR35
Duration: Approximately 2–3 months
Start Date: TBC
Security Clearance: Active UK SC Clearance – Mandatory
Day Rate: Competitive / DOE

About the Role:

We are seeking an experienced Network Architect (Data Centre) to support a UK defence programme involving the review and assessment of a live, multi-site data centre network environment.

The infrastructure is built around Cisco ACI across two data centres and includes Cisco routing and switching, Cisco ASA firewalls and F5 BIG-IP load balancing.

This is primarily an architecture, assessment and documentation assignment, rather than an operational network support role.

The successful candidate will assess the existing network environment, validate the current architecture against available documentation, produce formal design documentation, identify practical improvements, and assess the requirements for achieving true active/active resilience across both data centres.

The role will be delivered on a hybrid basis from Bristol or Milton Keynes, with on-site attendance required as appropriate.

Key Responsibilities:

• Assess the existing network estate across two data centres, including Cisco ACI fabric, routing, firewalling and load balancing.
• Review and validate existing and legacy network documentation against the live environment.
• Produce high-quality High Level Design (HLD) and Low Level Design (LLD) documentation.
• Take technical documentation through architecture review and formal sign-off.
• Identify low-risk network improvement opportunities and develop a structured, dependency-aware improvement roadmap.
• Assess the current implementation of the Cisco ACI application-centric policy model and recommend opportunities for improved utilisation.
• Review the existing Disaster Recovery capability and define the requirements for active/active operation across both data centres.
• Identify architectural constraints, migration requirements, potential service impacts and any additional hardware, software or licensing requirements.
• Work closely with architecture and network teams, participating in technical reviews and governance sessions.
• Respond to technical review comments and ensure agreed deliverables are completed to the required standard and timescale.

Essential Skills & Experience:

• Active UK SC Clearance – current and transferable. This is mandatory.
• Candidates who are only eligible for SC clearance cannot be considered for this assignment.
• Strong hands-on experience with Cisco ACI in production environments.
• In-depth understanding of the Cisco ACI policy model, including:
• Tenants
• VRFs
• Bridge Domains
• EPGs
• Contracts
• Strong experience with Cisco routing and switching.
• Experience with Cisco ASA firewalls.
• Experience with F5 BIG-IP load balancing.
• Demonstrable network architecture and design experience across multiple data centres.
• Strong understanding of Disaster Recovery and active/active data centre architectures.
• Proven experience producing professional HLDs, LLDs and technical assessment reports.
• Experience working directly with architecture teams and taking technical documentation through formal review and sign-off.
• Ability to work on a hybrid basis from Bristol or Milton Keynes, including on-site attendance when required.

Desirable Skills & Experience:

• Experience with Cisco ACI Multi-Pod or Multi-Site design and deployment.
• CCIE Data Center, CCNP Data Center, or equivalent relevant certification.
• Relevant F5 certification.
• Experience assessing and documenting live brownfield environments, particularly where existing documentation is incomplete or outdated.
• Previous experience within defence, government or other regulated environments.
• Experience working across different security classifications and within multi-supplier technical teams.

Key Deliverables:

The assignment is expected to include three principal areas of delivery:

As-Built Design Documentation – Review the existing environment and legacy documentation and produce updated HLD and LLD documentation reflecting the live network.

Network Review & Recommendations – Identify practical, low-risk improvements to the existing architecture, including opportunities to make better use of Cisco ACI's application-centric policy model, and present recommendations as a structured roadmap.

Disaster Recovery / Active-Active Assessment – Assess what would be required to achieve true active/active operation between the two data centres, covering existing constraints, implementation approach, impact on live services and additional infrastructure or licensing requirements.

Security Clearance:

Active UK SC Clearance is an essential requirement for this position.

Applicants must currently hold valid and transferable UK Security Clearance (SC). Unfortunately, candidates who do not currently hold SC clearance, even if they are eligible to obtain it, cannot be considered.

How to Apply:

Please apply with your up-to-date CV, clearly outlining your experience with:

Cisco ACI | Data Centre Architecture | Cisco ASA | F5 BIG-IP | HLD/LLD Documentation | DR & Active/Active Architecture

Pay: £2,150.00-£3,500.00 per month

Application question(s):

• Do you currently hold active and transferable UK Security Clearance (SC)?

Work Location: Hybrid remote in Bristol