About the Role
We are looking for an experienced Senior Network Engineer (L3) to join our network infrastructure team in London.
This is a hands-on technical role suited to an engineer with strong enterprise networking expertise and a proven track record of operating at Senior/L3 level.
You will be responsible for the design, implementation, support and troubleshooting of critical network infrastructure across a structured, change-controlled environment.
The role requires strong expertise across routing and switching, including OSPF, as well as hands-on experience with both Cisco and Arista platforms.
The successful candidate will also have experience working within financial services, where robust operational processes, CAB change control and high availability are essential.
Key Responsibilities
- Provide Senior/L3-level technical support for complex network infrastructure issues.
- Design, implement and troubleshoot enterprise routing and switching environments.
- Configure and support OSPF, VLANs, routing, ACLs and related network technologies.
- Work hands-on with Cisco and Arista networking hardware and platforms.
- Support network infrastructure required for IoT connectivity, including VLAN, routing and ACL configuration.
- Configure, troubleshoot and support multicast networking.
- Perform detailed network troubleshooting, including packet capture and analysis using appropriate tools.
- Participate in planned network changes, maintenance activities and scheduled change windows.
- Follow established CAB and change-control procedures, ensuring changes are appropriately planned, documented, tested and implemented.
- Support Saturday change windows when required, with occasional weekend work forming part of the role.
- Collaborate with infrastructure, security, application and other technology teams to resolve complex network issues.
- Communicate technical issues, risks and proposed solutions clearly to both technical and non-technical stakeholders.
- Contribute to continuous improvement of network resilience, operational processes and troubleshooting practices.
Essential Skills & Experience
- 8–10+ years' experience working as a Network Engineer, with demonstrable Senior/L3-level expertise.
- Strong hands-on experience with Routing & Switching, including OSPF.
- Extensive practical experience with both Cisco and Arista network hardware and platforms.
- CCNP certification required as a minimum.
- CCIE certification highly desirable.
- Previous experience working within a financial services environment.
- Strong understanding and practical experience of CAB/change-control procedures.
- Experience with VLANs, routing and ACLs, particularly in support of IoT connectivity.
- Hands-on experience configuring and troubleshooting multicast.
- Strong network troubleshooting capabilities, including packet capture and analysis.
- Excellent analytical and problem-solving skills.
- Strong communication and stakeholder management skills.
- Ability to work effectively within a structured, change-controlled operational environment.
- Willingness and availability to work Saturdays for scheduled network change windows.
Desirable
- CCIE certification.
- Experience supporting highly available, business-critical network environments.
- Broader exposure to network security, monitoring and automation technologies.
- Experience working across complex enterprise or data-centre network environments.