Principal Engineer - Networking (Packet Forwarding) (San Jose)

JOB SUMMARYAlkira’s Data Path Team owns the lowest and most performance-critical layer of the product: the fast path that forwards customer traffic at line rate, the encryption that protects it, and the address translation and tunneling that connect customer networks across clouds. At the core is a stateful, flow- and session-based engine that tracks every connection and applies routing, translation, and policy as packets pass through.As a Principal Engineer on this small, specialized team, split between the US and India, you’ll own several of the datapath’s most critical features end to end: building them in C, delivering them with the team, and keeping them healthy in production. You’ll stay hands-on in the code, help shape where the datapath goes next, and take point on the hardest production issues.RESPONSIBILITIESOwn several of the datapath’s most critical features end to end, from design through delivery to their long-term health in production.Design and build the most demanding parts of the C fastpath (VPP/DPDK) yourself; this is a hands-on role. Build and evolve the core of the datapath: the stateful flow and session engine, including connection tracking, NAT, policers, and per-packet, per-tenant policy. Own how customer networks connect securely across clouds, through IPsec and overlay tunnels like VXLAN, GRE, and GENEVE. Tune the datapath at the kernel, driver, and packet-path level as cloud providers ship new instance types and NIC features like SR-IOV and poll-mode drivers. Work with and lead other engineers to deliver datapath features and keep them stable once they ship. Take part in design and architecture reviews, work through the hard trade-offs, and mentor the engineers around you. Advise Solution Architects and customers on network design so their deployments hold up in production. Drive root-cause analysis on the hardest production issues at the packet and kernel level, partnering with the Routing, Backend, and Escalations teams. Share the on-call rotation. On-call is a required part of this role; the team provides round-the-clock coverage across the US and India for production datapath issues. Use AI tools like Claude Code to build tooling, write tests, and debug faster.REQUIREMENTS Expert C, with real depth in systems programming, memory, concurrency, and performance. This is the core skill for the fastpath. Years in the data plane, with a track record of owning and delivering complex, high-performance forwarding work.VPP and/or DPDK in production, or a comparable userspace fastpath framework, at real scale. Strong grasp of tunneling and encryption (VXLAN, IPsec, GRE) and how packets are encapsulated, encrypted, and translated. Network-security depth: encryption, secure tunneling, and how access and data policy is enforced in the data plane.Distributed-systems fundamentals: how the datapath’s control, state, and observability behave across a fleet. Strong Go and Python for the agents, exporters, tooling, and CLI around the fastpath. A track record of leading delivery: working with and leading engineers to ship and stabilize features, and staying calm and methodical when things break.BONUS POINTS Production IPsec implementationsCarrier-grade or large-scale production networking (switching, routing, or service-provider platforms). NIC and driver technologies like SR-IOV and DPDK poll-mode drivers, and adapting the datapath to new instance types.Cloud networking depth: how the major providers’ instance types and networking constructs affect datapath performance. A background in cloud security or zero-trust (ZTNA) at the data-plane level.Performance and scale tuning for packet-processing systems. + Building or integrating VNFs. Experience with AI development tools like Claude Code.ABOUT ALKIRAAlkira, a Lumen company, is building the future of enterprise networking: one programmable platform to connect, secure, and operate every cloud, site, partner, data center, and AI workload.Founded by Amir and Atif Khan, the creators of Viptela and pioneers of the SD-WAN market, Alkira was built to radically simplify how enterprises deploy and manage network infrastructure. Today, as part of Lumen, we are bringing that cloud-native operating model to a global network foundation trusted by the world’s largest enterprises.Our platform helps customers move faster without managing hardware, stitching together providers, or operating fragmented cloud networks. Teams can build and scale connectivity on demand, apply consistent security and segmentation, and gain visibility across distributed environments from one place.At Alkira, you’ll help shape the next chapter of networking: cloud-like consumption, private-network performance, and total control across the enterprise. We move fast, solve hard problems, and build technology that changes how global businesses connect.Join us and help build the future of networking.COMPENSATIONThe salary range for this position is $175,000 —$250,000 USD. Your actual base salary and level will be determined on a case by case basis and may vary based on the following considerations: job-related knowledge, skills, experience, education and location. DepartmentEngineering - R&DEmployment TypeFull-TimeMinimum ExperienceExperienced