Network Engineer

Matchtech; Harlow; On-site; GBP 70,000 - 110,000; Full time

Job summary

Matchtech is seeking a Security Cleared Senior Network Engineer on a contract basis to support Cisco ISE and Catalyst 9800 wireless platforms across secure network access and policy enforcement. This hands-on role focuses on engineering, troubleshooting, and implementation for 802.1X, MAB, and RADIUS—ensuring stable, secure operation.

The role includes leading migration strategies, designing HA deployments, and delivering clear documentation while coordinating with vendors and stakeholders.

Qualifications

• Security clearance (SC) required or eligible.
• Strong TCP/IP & OSI fundamentals.
• Experience with 802.1X, MAB, and RADIUS workflows.

Responsibilities

• Lead design, build, and replacement of legacy wireless with Cisco Catalyst 9800 WLC architecture.
• Define end-to-end wireless migration strategies including cutovers.
• Architect HA 9800 WLC deployments with SSO and redundancy.
• Design enterprise wireless solutions: SSID segmentation, VLAN mapping, RF optimization.
• Oversee Cisco ISE design, upgrades, patching, HA topology improvements.
• Optimize ISE policies: authentication, authorization, profiling, posture.
• Enhance secure network access via 802.1X and MAB.
• Drive performance improvements across wireless and AAA infra.
• Troubleshoot authentication & connectivity; use packet capture tools.
• Support change and release activities per governance.
• Coordinate with vendors (e.g., Cisco TAC) when needed.
• Produce clear technical docs and runbooks.

Skills

Security clearance (SC)

TCP/IP knowledge

802.1X

MAB

RADIUS

Troubleshooting

Documentation

Stakeholder comms

Education

CCNP Enterprise

CCNP Security

Cisco ISE Specialist

CWNA / CWNP

Tools

Cisco ISE

Catalyst 9800

Wireshark

TCPdump

Cisco DNA Center

ForcePoint Firewall

Job description

Our client, a prominent player in the Defence & Security sector, is seeking a Security Cleared Senior Network Engineer on a contract basis to support the delivery and optimisation of Cisco ISE (Identity Services Engine) and enterprise wireless (Catalyst 9800) platforms. This hands-on role focuses on engineering, troubleshooting, and implementation, particularly across secure network access (802.1X), policy enforcement, and wireless integration. You will play a key role in resolving complex issues, supporting upgrades, and ensuring stable, secure operation of critical network services.

Key Responsibilities:

• Lead the design, build, and replacement of legacy Cisco Wireless infrastructure with modern Cisco Catalyst 9800 WLC architecture, ensuring scalable, resilient, and high-performance wireless services
• Define and deliver end-to-end wireless migration strategies, including planning, staging, cutover execution, and post-implementation optimisation
• Architect and implement high-availability 9800 WLC deployments (SSO, redundancy models), ensuring minimal service disruption and operational resilience
• Design and implement enterprise wireless solutions, including SSID segmentation, policy profiles, VLAN mapping, RF optimisation, and seamless roaming
• Own the design, upgrade, and lifecycle management of Cisco ISE environments, including version upgrades, patching strategies, backup/restore, and HA topology improvements
• Optimise ISE policy frameworks, including authentication and authorisation policies, profiling, posture, and identity-based access control
• Design and enhance secure network access solutions leveraging 802.1X and MAB across both wired and wireless environments
• Drive performance improvements and service optimisation across wireless and AAA infrastructure, identifying bottlenecks and implementing streamlined, scalable solutions
• Troubleshoot complex authentication and connectivity issues, utilising packet capture and deep protocol analysis (Wireshark, TCPdump)
• Support change and release activities, ensuring adherence to governance and documentation standards
• Manage and escalate issues to vendors (e.g. Cisco TAC) where required
• Produce clear and accurate technical documentation, runbooks, and support artefacts

Job Requirements:

• Security clearance (SC cleared or the ability to become SC cleared)
• Strong understanding of TCP/IP and OSI model fundamentals
• Experience with VLANs, trunking, inter-VLAN routing, DHCP, DNS, NTP, BGP, OSPF, EIGRP
• Solid grounding in network security (AAA, segmentation, firewall troubleshooting)
• Ability to perform packet-level troubleshooting
• Strong experience deploying and supporting Cisco ISE in enterprise environments
• Expertise in 802.1X (wired and wireless), MAB, RADIUS authentication flows, and policy enforcement
• Deep understanding of CAPWAP, AP join process, and mobility/roaming in Cisco Catalyst 9800 (IOS-XE) WLCs
• Experience with RF design (RRM, DCA, channel/power tuning), high-density wireless environments, FlexConnect and local mode deployments
• Strong knowledge of WPA2/WPA3 Enterprise and integration with ISE (802.1X, MAB, role-based access)
• Experience with Cisco DNA Center
• Experience with ForcePoint Firewalls
• Suitable business and/or technical leadership skills in technology consulting
• Basic automation or API exposure (ISE/IOS-XE REST APIs)
• Relevant certifications such as CCNP Enterprise, CCNP Security, Cisco ISE Specialist, CWNA/CWNP

Soft Skills:

• Ability to diagnose cross-platform issues between ISE, WLC, and switching infrastructure
• Strong incident troubleshooting under pressure
• Clear and structured documentation of configurations, policies, and workflows
• Experience working within change and release management processes
• Effective stakeholder communication
• Experience with vendor escalation and TAC case management