Cisco Network Engineer / Subject Matter ExpertMust have an Active SC Clearance - Sponsorship for DV is available with this roleStep into a critical role as a Senior Cisco Network Engineer / Subject Matter Expert, supporting deployable classified systems within a secure environment in London. This position offers the opportunity to work on-site in a highly collaborative team, directly contributing to the stability, performance, and security of essential Defence networks.About the Role - Cisco Network Engineer / Subject Matter ExpertAs a Senior Cisco Network Engineer, you''ll deliver Level 3 support for LAN and WAN services across multiple security domains.You''ll manage incidents, troubleshoot escalations from 1st and 2nd line teams, and ensure swift resolution in mission-critical environments.Responsibilities include installation, configuration, maintenance, and diagnostics of Cisco network devices, as well as updating design documentation and managing cryptographic configurations.You''ll collaborate with resolver groups, NATO, and third parties to deliver technical and service changes.What We''re Looking For - Cisco Network Engineer / Subject Matter ExpertExpertise in Cisco network technologies including Nexus, IOS XE, Switch, and CUBE.Strong experience with AAA Management (ISE), QoS, ACL-ASA Firewalls, OSPF, BGP, and Spanning Tree.Proficiency with Firewall IPS/IDS and VoIP systems.Experience with NATO Gateways and vendor licensing models.Proven ability to lead incident reso