Senior Network Architect - freelance - hybrid, London, UK

Start date: Apr/ May 2026 
Location: London, UK (Hybrid — minimum 2 days per week in office) 
Industry: Financial Services / Banking

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A major banking group operating in EMEA is undergoing a significant infrastructure transformation programme, converging two separate network environments (a legacy three-tier Cisco campus network and an ACI spine-leaf fabric) alongside the integration of a European banking subsidiary. This is a hands-on senior architecture role requiring both strategic thinking and the ability to roll up sleeves and engage at detailed engineering levels. Requirements Must have Deep expertise in Cisco networking: Nexus (7K, 5K, 2K, 9K), IOS, NX-OS Strong working knowledge of Cisco ACI — ability to assess hybrid/pseudo-ACI deployments and define target-state app-centric or network-centric design Expert-level routing and switching: OSPF, BGP, EIGRP (including identification and remediation of misconfigurations) Data centre network design: spine-leaf, three-tier, convergence strategies Firewall architecture: Palo Alto (PA-40 series), Cisco ASA (legacy and migration) WAN/MPLS concepts and managed service architectures (NTT or similar providers) IP address management (IPAM) and DNS/DHCP strategies Network security design principles Familiarity with SD-WAN, cloud networking (Azure, AWS), and hybrid connectivity Advantageous Cisco CCIE (Routing & Switching or Data Centre) or equivalent demonstrable expertise Experience with network automation and orchestration tooling Knowledge of co-location and proximity hosting environments Understanding of financial services network requirements (trading floor, market data, payment systems) Soft skills Able to operate with ambiguity — comfortable in environments without fully defined organisational structure Strong communication skills: able to articulate complex technical problems to non-technical senior stakeholders Commercial awareness — understanding of total cost of ownership, vendor contracts, and infrastructure spend Collaborative and pragmatic, with the confidence to challenge incumbents and advocate for sound design principles Self-starter capable of providing direction to others with limited supervision