Network Engineer – Deployment and Support

Job description

About the Job As 'Network Engineer – Deployment and Support' within our Digital Technology Service Quality team, you will deploy, and support the enterprise network that connects Sanofi — LAN and WAN, WLAN, data center fabric, SD-WAN, and cloud networking across AWS and Azure. You will deploy infrastructure as code using Terraform, Ansible, and Python wherever the platform allows, and apply the same engineering rigor where it does not. You will own what you deploy — from design validation and automated pre-change checks through to day-two operations, capacity management, and incident response — ensuring our network estate remains accurate, performant, resilient, and ready for AI-enabled operations. Ready to get started? Our Team Digital Technology – Service Quality is at the heart of Sanofi's digital transformation. We deliver secure, resilient, and scalable infrastructure services that power business-critical applications and enable thousands of users across the enterprise. Our network engineering team owns the connectivity that every other service depends on — spanning offices, laboratories, manufacturing sites, data centers, and multiple cloud providers. Our team combines modern cloud platforms, automation-first engineering, and service excellence to support Sanofi's mission of chasing the miracles of science. About Sanofi We're an R&D-driven, AI-powered biopharma company committed to improving people's lives and delivering compelling growth. Our deep understanding of the immune system – and innovative pipeline – enables us to invent medicines and vaccines that treat and protect millions of people around the world. Together, we chase the miracles of science to improve people's lives. Main Responsibilities Network Deployment – Infrastructure as Code and Automation • Deploy cloud network infrastructure as code using Terraform, provisioning virtual networks and VPCs, subnets, route tables, peering, transit gateway and virtual WAN hubs, VPN gateways, and ExpressRoute and Direct Connect attachments across AWS and Azure, with reusable modules, remote state management, and plan review built into the change process • Deploy and maintain network configuration as code using Ansible, building reusable roles and templates for Cisco IOS and NX-OS, FortiOS, and Junos devices so that every deployment is repeatable, version-controlled, and auditable • Automate network provisioning and operational tasks in Python, consuming platform APIs — Cisco APIC for ACI fabric, Junos Space for Juniper estate management, Prisma SD-WAN and FatPipe controllers, and F5, Array, and AVI load balancer APIs • Automate vendor web consoles and portals that expose no usable API using Selenium, so that carrier portals, licensing, and legacy management interfaces do not force manual work • Use NEXUS as an AI agent within the engineering workflow to accelerate configuration generation and peer review, triage large log and packet-capture data sets, draft runbooks and knowledge articles, and scaffold Ansible and Python automation • Maintain Git as the source of truth for network configuration, with golden configuration templates, peer-reviewed changes, and a full version-controlled audit trail • Operate deployment pipelines for network change, including automated pre-change validation, standards compliance checks, and automated post-deployment verification of routing state, reachability, and interface health • Implement configuration drift detection and automated remediation, so deployed network configuration provably matches its declared intent • Codify network standards — naming, addressing, VLAN and VRF conventions, hardening baselines, and device software targets — and gate deployments against them • Drive deployments from an authoritative source of truth for IP addressing and inventory, rather than from spreadsheets • Implement zero-touch and templated onboarding so new switches, access points, and site routers reach a compliant baseline without manual console configuration Network Deployment – Engineering Delivery • Deploy network configuration items (CIs) including Cisco IOS and NX-OS switches and routers, Juniper devices, Aruba wireless controllers and access points, load balancers, and network appliances, from initial requirement through to validated production handover • Deliver network deployments at offices, laboratories, manufacturing sites, and on-premises data centres, including physical installation, rack and stack, structured cabling, optics, power and environmental checks, and high-availability pairing • Deliver hardware refresh, end-of-life replacement, and firmware and network OS upgrade campaigns across Cisco IOS/NX-OS, FortiOS, and Junos platforms, including RMA handling across the device estate • Execute controlled environment promotion (Dev to Pre-Prod to Production) with documented rollback and recovery plans for every deployment • Register all deployed CIs in the CMDB with correct class, attributes, relationships, ownership, location, and lifecycle status at point of deployment • Configure and maintain network discovery and SNMP so network CIs are correctly classified with accurate serial numbers, models, and discovery-source behavior • Onboard every newly deployed CI into monitoring, telemetry, configuration backup, and patching tooling before production sign-off • Produce and maintain as-built documentation, network topology diagrams, low-level designs, runbooks, and knowledge articles for all deployed infrastructure Routing, Switching and Networking Protocols • Implement and support routing across the estate — BGP and OSPF to a strong standard, static routing, route redistribution, filtering, and path selection • Design and implement VRF-based segregation and route separation across data center, campus, and WAN environments • Implement and support switching — VLANs, trunking, spanning tree, link aggregation, vPC, and first-hop redundancy on Cisco IOS and NX-OS platforms • Implement and support IPSec tunnelling for site-to-site and cloud connectivity, including encryption standards, rekeying, and failover behavior • Design and implement addressing and subnetting to enterprise standards, maintaining IP address management accuracy as deployments land • Implement quality of service, multicast, and traffic engineering where application or manufacturing requirements demand it • Implement network zones, VLANs, and segmentation in line with security architecture and zoning standards, in partnership with the network security team Data Centre, SDN and SD-WAN • Deploy and support data center fabrics built on Cisco ACI, using Cisco APIC for policy, tenant, and endpoint group configuration, and VXLAN overlays for tenant connectivity • Deploy and support leaf-spine data center architectures, including fabric expansion, overlay design, and integration with compute and storage connectivity requirements • Deploy and support SD-WAN across Palo Alto Prisma SD-WAN (CloudGenix) and FatPipe platforms, including overlay design, transport independence, application-aware routing policy, and failover behavior • Coordinate circuit delivery with carriers and service providers, managing lead times, handover testing, and acceptance • Monitor and manage WAN capacity, latency, and cost, recommending upgrades, re-homing, or transport changes Wireless Networking – WLAN • Deploy, configure, and support Aruba wireless infrastructure, including controllers, access points, and centralized WLAN management • Deliver wireless design and validation, including predictive design, site surveys, RF tuning, channel and power planning, and post-deployment validation surveys • Support wireless authentication integration and guest access in partnership with the network security and identity teams • Troubleshoot wireless performance, roaming, coverage, and interference issues, including in warehouse, laboratory, and manufacturing envi