Senior/Lead Software Engineer, Packet Forwarding
Confirmed on the employer's own hiring board on Sep 26, 2026. First seen by Alion on Sep 22, 2026. Arista Networks scores B on the Alion truth index.
Arista Networks is an industry leader in data-driven, client-to-cloud networking for large data center, campus and routing environments. What sets us apart is our relentless pursuit of innovation. We leverage the latest advancements in cloud computing, artificial intelligence, and software-defined networking to provide our clients with a competitive edge in an increasingly interconnected world. Our solutions are designed to not only meet the current demands of the digital landscape but to also anticipate and adapt to future challenges.
At Arista we value the diversity of thought and perspectives that each employee brings to the table. We believe that fostering an inclusive environment, where individuals from various backgrounds and experiences feel welcome, is essential for driving creativity and innovation.
Our commitment to excellence has earned us several prestigious awards, such as Best Engineering Team, Best Company for Diversity, Compensation, and Work-Life Balance. At Arista, we take pride in our track record of success and strive to maintain the highest standards of quality and performance in everything we do.
Who You'll Work With
Arista Networks is looking for world-class Senior/Lead Packet Forwarding Engine (PFE) Software Engineers.
As a Senior/Lead PFE Software Engineer, you will collaborate and work with customers, product management and engineers to design and build novel packet forwarding features in EOS that help networks run effectively and efficiently. You will need to understand the packet forwarding architecture in depth and figure out how to apply it optimally to solve customer problems. You will design the packet forwarding flow, design data structures and algorithms to render the packet forwarding state used by the forwarding engine for efficiency and scale, and tie it all together with the higher layers.
In this role, you will get to confront complex, multi-dimensional problems such as
“Upgrade software on a switch with no more than a few milliseconds of downtime”
“Render a routing table with >1M routes into the forwarding path on a router with a hundred forwarding chips”
that are open ended, challenging, fun and require strong problem solving skills.
Arista Software Engineering roles demand a strong and broad software engineering background. While the primary focus area for this role is packet forwarding, the role will cover all aspects of software development spanning the addition of new features, debugging problems and fine tuning code for scalability and performance. You will own your projects from definition to deployment and customer interactions, and you will be responsible for the quality of everything you deliver.
Arista Software Engineering prides itself on a supportive and growth oriented culture. Over time, as your interests change, coupled with evolving business needs you will have the opportunity to switch from packet forwarding to other areas, if you like.
What You’ll Do
- Interface with customers and product management to define packet forwarding features and solutions.
- Architect, design and manage the development of these features.
- Develop and maintain features using C, C++ and Python, review and contribute to functional and design specifications. Build automated tests and test infrastructure to test the features.
- Provide technical leadership across features, projects and tools.
- Work with Customer Support Engineers and customers to analyze, mitigate and fix problems in customer networks.
- Work with the System Test Engineers to analyze problems found in their tests and provide fixes for those problems.
- Mentor new and junior engineers to bring them up to speed in Arista's software development environment.
- BS Computer Science/Electrical Engineering/Computer Engineering + 8 years experience, or MS Computer Science/Electrical Engineering/Computer Engineering + 6 years experience, or Ph.D. in Computer Science/Electrical Engineering/Computer Engineering + 3 years experience, or equivalent work experience
- Expert knowledge of C or C++ and Python.
- Knowledge of UNIX or Linux
- Understanding of IP networking and/or distributed systems
- Experience working with packet forwarding chips and pipelines is a plus
- Applied understanding of software engineering principles
- Strong problem solving and software troubleshooting skills
- Ability to design a solution and implement features independently.
- Ability to work in small teams.
Arista Networks is an equal opportunity employer. Arista makes all hiring and employment-related decisions in a non-discriminatory manner without regard to race, color, religion, sex, sexual orientation, gender identity, national origin or any other factor determined to be unlawful under applicable federal, state, or law law. All your information will be kept confidential according to EEO guidelines.