Principal Network Engineer – Cisco (Hybrid, London)

About the role

We are partnering with a fast‑growing full‑fibre broadband provider that is rolling out next‑generation FTTP infrastructure across London. The Principal Network Engineer will act as the technical authority, leading design, delivery and optimisation of a carrier‑grade network in a high‑performance environment.

Key responsibilities

• Lead the design, delivery and optimisation of network infrastructure projects.
• Own the full project lifecycle from scoping through implementation and continuous improvement.
• Serve as the final escalation point for complex network faults and incidents.
• Ensure network availability and performance meet strict SLA targets.
• Design and implement scalable, resilient carrier‑grade solutions.
• Monitor network health and respond proactively to alarms.
• Produce high‑quality documentation (HLD, LLD, migration plans, procedures).
• Collaborate with internal teams, vendors and stakeholders to deliver solutions.
• Provide out‑of‑hours support as part of an on‑call rota.
• Mentor and support junior engineers.

Required profile

• Strong experience in network project delivery, preferably in an ISP/telco environment.
• Proven expertise with carrier‑grade Cisco networking equipment.
• Deep knowledge of BGP, OSPF, IS‑IS, MPLS, MPLS VPNs, IPv6 and multicast.
• Experience with firewalls, network security and packet‑capture analysis.
• Hands‑on experience with network monitoring tools such as SolarWinds, Nagios or PRTG.
• Ability to work autonomously and lead technical projects.
• Experience producing detailed technical documentation.
• CCIE (Service Provider or Enterprise) or equivalent certification highly desirable.

Required skills

• Cisco networking equipment
• BGP
• OSPF
• IS‑IS
• MPLS & MPLS VPN
• IPv6
• Multicast networking
• Firewalls & network security
• Packet capture analysis
• SolarWinds, Nagios, PRTG
• Scripting/automation

What we offer

• Competitive salary £80,000‑£90,000 per year
• Comprehensive benefits package
• Hybrid working model (60% office, 40% remote)