Senior RDMA Performance Engineer

Codilime; Polska; Hybrid; PLN 240,000 - 320,000; Full time

Job summary

Codilime is seeking an RDMA Performance engineer to join our project team focusing on AI networking environments. You will configure and troubleshoot NVIDIA/Mellanox Spectrum switches and ConnectX NICs, tuning congestion control for AI workloads and optimizing throughput and latency in data centers.

You’ll work with NCCL, RDMA, and QoS while automating tasks with AI agents and documenting your designs and benchmarking results for internal and client reviews.

Qualifications

• 7+ years of professional experience in network engineering, with 3+ years in data center design.
• Hands-on experience with BGP, EVPN/VXLAN, LACP and ECMP.
• Deep knowledge of AI-dedicated data center designs (ROD/RUD) and practical deployment.
• Proven experience configuring, managing and troubleshooting NVIDIA/Mellanox Spectrum switches and ConnectX NICs.
• Deep understanding of RoCEv2, PFC, and ECN for AI data centers.
• Ability to tune switch buffers and implement QoS policies.
• Experience benchmarking RDMA-enabled fabrics and NCCL.
• Ability to leverage AI agents/tools to automate tasks and testing.
• Strong technical documentation and professional English communication.

Responsibilities

• Configure, troubleshoot and maintain NVIDIA/Mellanox Spectrum switches and ConnectX NICs.
• Implement and tune congestion control for AI workloads (RoCEv2, PFC, ECN).
• Tune network environments for maximum throughput and minimal latency.
• Benchmark and validate AI-ready data center fabrics using RDMA and NCCL.
• Automate tasks using AI agents and testing tools; analyze telemetry.
• Document network designs, configurations and benchmarking results.

Skills

Network engineering

Data center design

BGP

EVPN/VXLAN

LACP

ECMP

QoS tuning

RDMA

NCCL

English communication

Tools

NVIDIA/Mellanox Spectrum switches

ConnectX NICs

pyATS

NAPALM

Batfish

Nornir

NetBox

CI/CD pipelines

Job description

Get to know us better

CodiLime is a software and network engineering industry expert and the first-choice service partner for top global networking hardware providers, software providers and telecoms. We create proofs-of-concept, help our clients build new products, nurture existing ones and provide services in production environments. Our clients include both tech startups and big players in various industries and geographic locations (US, Japan, Israel, Europe).

While no longer a startup - we have 250+ people on board and have been operating since 2011 we’ve kept our people-oriented culture. Our values are simple:

• Act to deliver.

• Disrupt to grow.

• Team up to win.

The project and the team

The project involves SONiC validation on NVIDIA Spectrum-Based Platforms for AI Networking.

What else you should know:

• We use Agile methodology.

• The team operates within a startup environment.

• The client is based in the US.

We work on multiple interesting projects at the time, so it may happen that we’ll invite you to the interview for another project if we see that your competencies and profile are well suited for it.

Your role

As a part of the project team, you will be responsible for:

• Configure, troubleshoot, and maintain NVIDIA/Mellanox Spectrum switches and ConnectX Network Interface Cards (NICs).

• Implement and tune advanced congestion control mechanisms essential for AI workloads, including RoCEv2, Priority-based Flow Control (PFC), and Explicit Congestion Notification (ECN).

• Optimize network environments to ensure maximum throughput, minimal latency, and minimal Job Completion Time (JCT) by performing setup tuning.

• Conduct extensive performance benchmarking and validation testing on AI-ready data center fabrics utilizing RDMA and the NVIDIA Collective Communication Library (NCCL).

• Leverage AI agents and specialized tools to automate routine network tasks, conduct rigorous testing, and analyze network telemetry.

• Author and maintain clear, high-quality technical documentation detailing network designs, configurations, and benchmarking results.

Do we have a match?

As a RDMA Performance engineer you must meet the following criteria:

• 7+ years of professional experiencein network engineering, with preferably 3+ years specifically focused on data center network design and architecture.

• Hands-on experience configuring and troubleshooting core network protocols and technologies, including BGP, EVPN/VXLAN, LACP, and ECMP.

• Deep understanding of AI-dedicated data center designs, including Rail-Optimized Design (ROD) and Rail-Unified Design (RUD) topologies, coupled with practical, hands-on experience configuring and deploying them.

• Proven experience configuring, managing, and troubleshooting NVIDIA/Mellanox Spectrum switches and ConnectX Network Interface Cards (NICs).

• Deep understanding of the protocols and congestion control mechanisms required for AI-dedicated data centers, specifically RoCEv2, Priority-based Flow Control (PFC), and Explicit Congestion Notification (ECN).

• Demonstrated ability to tune and optimize network environments, with specific focus on switch buffer tuning and the implementation of Quality of Service (QoS) policies.

• Experience conducting performance benchmarking and validation for AI-ready data center fabrics utilizing RDMA and the NVIDIA Collective Communication Library (NCCL).

• Demonstrated ability to leverage AI agents/tools to automate tasks, testing, and analysis

• Strong technical documentation skills and professional English communication

Beyond the criteria above, we would appreciate the nice-to-haves:

• Professional-level certifications (CCNP/CCIE Enterprise/DC, JNCIP or equivalent)

• Hands-on experience with network automation & validation frameworks (pyATS, NAPALM, Batfish, Nornir, NetBox)

• Exposure to CI/CD pipelines (GitLab CI, GitHub Actions, Jenkins) and IaC concepts

More reasons to join us

• Flexible working hours and approach to work: fully remotely, in the office or hybrid

• Professional growth supported by internal training sessions and a training budget

• Solid onboarding with a hands-on approach to give you an easy start

• A great atmosphere among professionals who are passionate about their work

• The ability to change the project you work on