Senior Network Engineer

Marks Sattin; Greater London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Marks Sattin is seeking a Network Engineer to lead the design, deployment, and evolution of a global network spanning data centres, trading environments, and enterprise locations.

The role emphasizes end-to-end project ownership, third-party connectivity, and senior technical escalation. You will implement EVPN/VXLAN with Arista EOS, build automation, and drive observability with Grafana and Splunk.

Qualifications

• CCNP Routing & Switching (or equivalent)
• JNCIP-Junos (or equivalent)
• Foundational wireless certification
• Degree in Computer Science/Engineering (or equivalent practical experience)
• Strong routing/switching design across Junos, Arista EOS, Cisco IOS
• EVPN/VXLAN design and implementation experience on Arista
• Working knowledge of Palo Alto firewalls and F5 load balancers
• Automation/scripting using Python and Ansible in production network environments
• Incident leadership, RCA, and remediation
• Mentoring others and producing clear technical documentation

Responsibilities

• Design and implement data centre and enterprise network solutions (new builds, refreshes, migrations).
• Deliver projects end-to-end: HLD/LLD documentation, build, testing, cutover, and operational handover.
• Turn up and support third-party services, including CDN, extranet, and VPN connectivity.
• Lead routing and switching design across Juniper, Arista, and Cisco platforms (BGP, OSPF, EIGRP, redistribution, filtering/policy).
• Design, build and support EVPN/VXLAN fabrics using Arista EOS.
• Act as senior escalation for major/complex incidents: triage, RCA, and permanent fixes.
• Build and maintain automation/tooling using Python, Ansible, and Git to reduce manual effort.
• Improve observability and operations using Grafana, Splunk, ServiceNow, and apply AI tools for proactive troubleshooting.
• Maintain infrastructure hygiene: code upgrades, EOL replacements, audits, and standards adherence.
• Mentor junior engineers and ensure strong documentation and cross-region handovers.

Skills

CCNP Routing & Switching

JNCIP-Junos

Wireless certification

Network design

Leadership

Documentation

Education

Degree in Computer Science/Engineering

Tools

Python

Ansible

Git

Job description

A global, high-performance financial services organisation is seeking a Network Engineer to lead the design, deployment, and ongoing evolution of its worldwide network estate spanning data centres, trading environments, and enterprise locations.

This role will take end-to-end ownership of network project delivery, oversee third-party connectivity turn-ups, and act as the senior technical escalation point for complex incidents-while driving automation and AI-enabled operational improvements.

What you'll be doing

• Design and implement data centre and enterprise network solutions (new builds, refreshes, migrations).
• Deliver projects end-to-end: HLD/LLD documentation, build, testing, cutover, and operational handover.
• Turn up and support third-party services, including CDN, extranet, and VPN connectivity.
• Lead routing and switching design across Juniper, Arista, and Cisco platforms (BGP, OSPF, EIGRP, redistribution, filtering/policy).
• Design, build and support EVPN/VXLAN fabrics using Arista EOS.
• Act as senior escalation for major/complex incidents: triage, RCA, and permanent fixes.
• Build and maintain automation/tooling using Python, Ansible, and Git to reduce manual effort.
• Improve observability and operations using Grafana, Splunk, ServiceNow, and apply AI tools for proactive troubleshooting.
• Maintain infrastructure hygiene: code upgrades, EOL replacements, audits, and standards adherence.
• Mentor junior engineers and ensure strong documentation and cross-region handovers.

What we're looking for

• CCNP Routing & Switching (or equivalent capability).
• JNCIP-Junos (or equivalent capability).
• Foundational wireless certification (required).
• Degree in Computer Science/Engineering (or equivalent practical experience).
• Strong routing/switching design background across Junos, Arista EOS, Cisco IOS (BGP/OSPF/EIGRP).
• Hands-on EVPN/VXLAN design and implementation experience on Arista.
• Working knowledge of Palo Alto firewalls and F5 load balancers.
• Proven automation/scripting experience using Python and Ansible in production network environments.
• Calm under pressure with a track record in incident leadership, RCA, and remediation.
• Experience mentoring others and producing clear, high-quality technical documentation.