Senior Software Engineer, AI Cluster Networking Performance Engineer

Cisco Systems, Inc.; Milpitas (CA); On-site; USD 168,000 - 245,000; Full time

Benefits offered by this job

401(k) matching

Medical, dental, vision insurance

Paid parental leave

Disability coverage

Life insurance

Restricted stock units (RSUs)

Job summary

Cisco Systems, Inc. is hiring a Senior Software Engineer to debug, profile, and optimize the AI cluster networking and GPU performance stack from boot to application level.

You will tackle kernel-level failures, PCIe issues, driver behavior, and network latency while tuning RDMA/RoCEv2, NCCL, and NIC performance. The role requires strong C/C++/Python skills and hands-on experience with Linux kernel and distributed systems debugging, in a fast-paced, hardware-influenced environment.

Qualifications

• Bachelor's degree or higher with 4+ years of relevant experience in Linux kernel, networking, GPU, or distributed systems debugging
• Proficiency in C/C++, C++, Python; experience with user-mode and kernel-mode drivers
• Experience with Linux network stack, RDMA/RoCEv2, NCCL, PCIe; strong debugging and profiling skills

Responsibilities

• Debug, profile, and optimize the AI cluster networking and GPU performance stack across boot-time to application level
• Investigate kernel-level failures, PCIe issues, driver behavior, and network latency
• Tune RDMA/RoCEv2, NCCL, SmartNIC/DPU, NIC queues, congestion, throughput, and collective communications
• Read and correlate traces from host CPUs, PCIe switches, SmartNICs, and GPU streams
• Capture and analyze Wireshark packets, system logs, and observability data
• Collaborate with hardware and software teams to remove end-to-end bottlenecks

Skills

Linux kernel debugging and profiling

Networking

GPU performance tuning

Distributed systems debugging

C/C++/Python programming

Education

Bachelor's degree in CS/EE

Tools

NVIDIA Nsight

Nsight profiling tools

NVIDIA diagnostic tooling

Wireshark

RDMA/NCCL tooling

Job description

The application window is expected to close on: 11/29/2026

Meet the Team

Cisco Validated Infrastructure Services (CVIS) establishes and proves the performance of large AI clusters before they are handed over to customers. We deploy each cluster, validate it against performance baselines, and deliver the evidence that it is ready for service. The platform behind that work is full stack. It combines workflow and API services, network and infrastructure automation, and the UI used to run validation across labs and customer environments.

Your Impact

As a Senior Software Engineer, you will be responsible for things like debugging, profiling and optimizing the full AI cluster networking and GPU performance stack, from boot-time and PCIe behavior through Linux kernel, SmartNIC/DPU, RDMA, NCCL, and application-level collective communication. You will:

• Investigate kernel-level failures, boot-time anomalies, PCIe link issues, driver behavior, and network latency.
• Diagnose and tune RDMA/RoCEv2, NCCL, SmartNIC/DPU, NIC queues, congestion, throughput, and collective communications.
• Read and correlate unified hardware traces across host CPUs, PCIe switches, SmartNICs, and GPU compute streams.
• Capture and analyze Wireshark packets, system logs, NVIDIA support logs, traces, profiles, and observability data.
• Partner with hardware and software teams to eliminate end-to-end bottlenecks.

Minimum Qualifications

• Bachelors + 7 years of related experience, or Masters + 4 years of related experience, or PHD +1 year of related experience or equivalent related work experience.
• 4+ years of experience working with Linux kernel, networking, GPU, and distributed-systems debugging skills.
• Experience writing code with C/C++/Python and experience with user-mode and kernel-mode drivers.
• Experience with Linux network stack, RDMA/RoCEv2, NCCL, PCIe, and performance profiling.
• Prior experience working with reason from packet captures, traces, counters, logs, and reproducible benchmarks.

Preferred Qualifications

• SmartNIC/DPU optimization and DOCA SDK experience.
• Cisco switching, AI cluster network fabrics, multi-plane/ToR designs, and high-speed Ethernet or InfiniBand environments.
• Familiarity with NVIDIA diagnostic tooling, Nsight/profiling tools, kernel tracing, and observability platforms.

Why Cisco?

At Cisco, we're revolutionizing how data and infrastructure connect and protect organizations in the AI era - and beyond. We've been innovating fearlessly for 40 years to create solutions that power how humans and technology work together across the physical and digital worlds. These solutions provide customers with unparalleled security, visibility, and insights across the entire digital footprint.

Fueled by the depth and breadth of our technology, we experiment and create meaningful solutions. Add to that our worldwide network of doers and experts, and you'll see that the opportunities to grow and build are limitless. We work as a team, collaborating with empathy to make really big things happen on a global scale. Because our solutions are everywhere, our impact is everywhere.

We are Cisco, and our power starts with you.

Message to applicants applying to work in the U.S. and/or Canada

The starting salary range posted for this position is $167,700.00 to $245,200.00 and reflects the projected salary range for new hires in this position in U.S. and/or Canada locations, not including incentive compensation*, equity, or benefits.

Individual pay is determined by the candidate's hiring location, market conditions, job-related skillset, experience, qualifications, education, certifications, and/or training. The full salary range for certain locations is listed below. For locations not listed below, the recruiter can share more details about compensation for the role in your location during the hiring process.

Benefits and Compensation

U.S. employees are offered benefits, subject to Cisco's plan eligibility rules, which include medical, dental and vision insurance, a 401(k) plan with a Cisco matching contribution, paid parental leave, short and long-term disability coverage, and basic life insurance. Please see the Cisco careers site to discover more benefits and perks. Employees may be eligible to receive grants of Cisco restricted stock units, which vest following continued employment with Cisco for defined periods of time.

Paid Time Away

• 10 paid holidays per full calendar year, plus 1 floating holiday for non-exempt employees
• 1 paid day off for employee's birthday, paid year-end holiday shutdown, and 4 paid days off for personal wellness determined by Cisco
• Non-exempt employees** receive 16 days of paid vacation time per full calendar year, accrued at rate of 4.92 hours per pay period for full-time employees
• Exempt employees participate in Cisco's flexible vacation time off program, which has no defined limit on how much vacation time eligible employees may use (subject to availability and some business limitations)
• 80 hours of sick time off provided on hire date and each January 1st thereafter, and up to 80 hours of unused sick time carried forward from one calendar year to the next
• Additional paid time away may be requested to deal with critical or emergency issues for family members
• Optional 10 paid days per full calendar year to volunteer

Bonuses

For non-sales roles, employees are also eligible to earn annual bonuses subject to Cisco's policies.

Employees on sales plans earn performance-based incentive pay on top of their base salary, which is split between quota and non-quota components, subject to the applicable Cisco plan. For quota-based incentive pay, Cisco typically pays as follows:

• .75% of incentive target for each 1% of revenue attainment up to 50% of quota;
• 1.5% of incentive target for each 1% of attainment between 50% and 75%;
• 1% of incentive target for each 1% of attainment between 75% and 100%; and
• Once performance exceeds 100% attainment, incentive rates are at or above 1% for each 1% of attainment with no cap on incentive compensation.

For non-quota-based sales performance elements such as strategic sales objectives, Cisco may pay 0% up to 125% of target. Cisco sales plans do not have a minimum threshold of performance for sales incentive compensation to be paid.

Salary Ranges by State

The applicable full salary ranges for this position, by specific state, are listed below:

New York City Metro Area:

$167,700.00 - $282,000.00

Non-Metro New York state & Washington state:

$149,100.00 - $250,900.00

* For quota-based sales roles on Cisco's sales plan, the ranges provided in this posting include base pay and sales target incentive compensation combined.

** Employees in Illinois, whether exempt or non-exempt, will participate in a unique time off program to meet local requirements.