L3 Network Operations Engineer

Company:Marsh
Description:
We are seeking a talented individual to join our Network Operations team at Marsh. This role will be based in Cluj-Napoca and follows a hybrid working model, with a requirement to work at least three days per week in the office.
As an L3 Network Operations Engineer, you will act as a senior escalation point for complex network incidents, service issues, and network changes.
This is a hands-on, operational and delivery-focused role with a strong emphasis on network troubleshooting, problem resolution, remediation, and implementation.
You will support enterprise network services across LAN, WAN, branch connectivity, WiFi, routing, switching, and on-premises network infrastructure. You will work closely with internal teams, carriers, vendors, and technology partners to restore services, implement changes safely, and improve network reliability.
Working pattern
Hybrid working model with an expectation of time in the office and time working from home.
Standard business hours, Monday to Friday.
Global follow-the-sun support model across EMEA, APAC, and the Americas, with structured handovers between regions.
Weekend on-call rota for major incidents only; shared across the full team with each person covering one weekend per rotation cycle.
We will count on you to:
Provide L3 escalation support for complex network incidents and major service disruptions.
Lead technical triage, fault isolation, remediation, and service restoration activities.
Troubleshoot complex issues across LAN, WAN, branch connectivity, routing, switching, WiFi, and on-premises network infrastructure.
Investigate end-to-end connectivity issues affecting users, offices, branches, applications, and network services.
Troubleshoot issues across relevant network layers and protocols, including IP, TCP, DNS, DHCP, HTTP/HTTPS, and TLS where applicable to connectivity and service diagnosis.
Analyze network traffic flows, routing paths, interface behavior, and connectivity dependencies to identify root causes.
Support and troubleshoot WAN and branch connectivity services, including routing, pathing, latency, packet loss, carrier issues, circuits, and site-to-site communication.
Support branch LAN and WLAN environments, including local switching, wireless access, and site-level connectivity issues.
Support and troubleshoot enterprise WiFi/WLAN environments, including access points, controllers, switching dependencies, wireless connectivity, and performance-related issues.
Configure, support, and troubleshoot Cisco and Arista routers and switches.
Work with Cisco multilayer switching environments, including VLANs, trunking, Spanning Tree, SVIs, inter-VLAN routing, routing protocols, and high-availability configurations.
Support network resilience and failover activities across enterprise and branch environments.
Work with carriers, vendors, managed service providers, and technology partners during network outages and complex service issues.
Deliver network changes safely and effectively through ITIL-aligned governance.
Prepare implementation plans, risk assessments, validation steps, and rollback procedures.
Implement and support network upgrades, migrations, hardware replacements, connectivity changes, site deployments, and infrastructure improvements.
Perform pre-change checks, post-change validation, and service verification.
Participate in problem management activities and identify recurring issues and opportunities for permanent remediation.
Produce high-quality technical documentation, network diagrams, ITSM updates, incident records, problem records, implementation records, and closure notes.
Contribute to knowledge articles, troubleshooting procedures, technical standards, and continuous improvement initiatives.
Participate in structured handovers across global regions and ensure that relevant technical information is communicated clearly.
Communicate effectively with technical teams, service owners, business stakeholders, carriers, vendors, and external suppliers.
What you need to have
Proven experience in L3 Network Operations, senior network support, or a similar role within an enterprise, NOC, or infrastructure operations environment.
Strong hands-on troubleshooting experience across: LAN and WAN connectivityBranch networksRouting and switchingNetwork paths and traffic flowsNetwork availability and performance issuesWiFi and WLAN environmentsOn-premises network infrastructure
Solid experience with Cisco multilayer switching, including: Layer 2 and Layer 3 troubleshootingVLANs and trunkingSpanning TreeSVIsInter-VLAN routingRouting protocolsHigh-availability and resiliency concepts
Professional experience with Cisco and/or Arista routers and switches.
Practical experience troubleshooting WAN connectivity, circuits, carrier issues, routing problems, and branch outages.
Experience supporting enterprise WiFi environments, including wireless access points, controllers, switching dependencies, and wireless connectivity issues.
Strong understanding of core networking concepts and protocols, including TCP/IP, DNS, DHCP, HTTP, HTTPS, and TLS at a troubleshooting level.
Experience analyzing network symptoms, isolating root causes, and implementing effective remediation.
Experience working with telecommunications providers, vendors, and third-party support organizations.
Proven ability to support major incidents and complex technical escalations.
Strong change management discipline within an ITIL framework, including Incident, Problem, and Change processes.
Ability to produce clear technical documentation and communicate effectively with both technical and non-technical stakeholders.
Ability to work independently while collaborating effectively within a global team.
Willingness to participate in the shared weekend on-call rota for major incidents.
\What makes you stand out?
Experience working as a Network Implementation Engineer, Senior Network Engineer, L3 Network Engineer, Network Infrastructure Engineer, Branch Network Engineer, or Network Operations Engineer.
Experience with enterprise branch network deployments, migrations, rollouts, and infrastructure refreshes.
Experience supporting new site openings, office relocations, branch migrations, and network hardware replacement projects.
Strong experience with large-scale Cisco and/or Arista environments.
Advanced enterprise WiFi experience, including wireless controllers, access points, WLAN design, site deployments, and complex wireless troubleshooting.
Experience with SD-WAN platforms and branch connectivity solutions.
Familiarity with hybrid network environments and cloud-connected enterprise networks.
Experience with network automation or configuration tools.
Relevant Cisco, Arista, networking, or ITIL certifications.
Familiarity with security technologies such as firewalls, cloud security controls, Zero Trust solutions, or segmentation technologies.
Previous exposure to load-balancing or traffic-management technologies.
Experience supporting network changes and implementations in a large, geographically distributed organization.
Why join our team:
We help you be your best through professional development opportunities, interesting work, and supportive leaders.
We foster a vibrant and inclusive culture where you can work with talented colleagues to create new solutions and have an impact for colleagues, clients, and communities.
Our scale enables us to provide a range of career opportunities, as well as benefits and rewards to enhance your well-being.
A yearly budget and the opportunity to build your flexible benefits package, up to 20% of your annual salary.
30+ days off, including legal days, birthday leave, public holiday replacements, and benefits options.
Performance bonus scheme.
Matching charity contributions, charity days off, and the Pay it Forward charity challenge.
Core benefits including pension, life insurance, medical insurance, meal vouchers, and travel insurance.
Professional development and learning opportuniti