Software Engineer - Cloud Native BNG Solution Testing, Scale & Performance, Python | 4-8 years

Meet the Team

The Cisco cnBNG Solution Testing team validates carrier-grade broadband solutions running on IOS-XR routing platforms, including Cisco 8000, ASR 9000, and NCS 5500/5700. Our focus is ensuring that cnBNG solutions meet demanding service-provider requirements for functionality, scale, performance, resiliency, interoperability, and operational readiness. We validate the cnBNG solution end-to-end across Control Plane and User Plane functions, subscriber protocols, forwarding, high availability, and platform infrastructure. We operate at the intersection of software, hardware, networking, and customer deployments, with an automation-first approach and responsible adoption of AI-assisted engineering practices.

Your Impact

As a Software Engineer in the cnBNG Solution Testing team, you will own end-to-end solution, scale, performance, and resiliency validation of cnBNG deployments.

You will design sophisticated service-provider network topologies, develop comprehensive test strategies, automate large-scale subscriber and traffic scenarios, and validate the system under realistic customer workloads. You will work extensively with traffic-generation platforms such as Keysight IXIA and Spirent, analyze system and forwarding performance, identify bottlenecks, and collaborate with development teams to drive defects to resolution.

• You will play a critical role in assessing product quality and providing evidence-based recommendations for release readiness.
• Design and implement end-to-end cnBNG solution testing across Control Plane, User Plane,subscriber management, forwarding, platform infrastructure, and external network elements.
• Own scale and performance qualification, including subscriber scale, session setup/teardown rates, throughput, latency, packet loss, convergence, CPU/memory utilization, and system behavior under sustained load.
• Develop realistic service-provider test topologies covering PPPoE, IPoE, DHCPv4/v6, PPP, RADIUS/CoA, L2TP, subscriber policies, accounting, QoS, and subscriber lifecycle scenarios.
• Build and validate large-scale cnBNG deployments with multiple Control Plane and User Plane nodes. Develop strong proficiency with Keysight IXIA and Spirent traffic generators, including subscriber emulation, protocol emulation, traffic generation, traffic analysis, performance benchmarking, and large-scale test execution.
• Create traffic profiles that model real-world broadband deployments, including mixed IPv4/IPv6 traffic, multiple packet sizes, bidirectional traffic, QoS classes, and subscriber service profiles.
• Validate CUPS / CP-UP separation, including session programming, state synchronization, state replay, reconciliation, Control Plane and User Plane failures, and recovery scenarios.
• Perform comprehensive high-availability and resiliency testing, including SRG geo/warm standby, process restart, node failures, link failures, ISSU, NSR/NSF, control-plane failures, and subscriber session continuity.
• Validate IOS-XR forwarding functionality including L2/L3 forwarding, FIB/adjacency, MPLS/L3VPN, H-QoS/policing, ACLs, mirroring, OAM/BFD, slowpath, and NPU forwarding behavior.
• Develop and maintain scalable Python-based test automation using pyATS/Genie or equivalent frameworks, integrating tests into CI/CD pipelines and regression suites.
• Build reusable automation libraries for topology setup, subscriber provisioning, traffic generation, fault injection, statistics collection, verification, and automated result analysis.
• Analyze performance trends and identify bottlenecks across software, forwarding hardware, NPU resources, CPU, memory, and control-plane interactions.
• Perform soak, longevity, stress, negative, boundary, and capacity testing to uncover issues that may only appear under sustained or extreme workloads.
• Validate subscriber QoS, accounting, lawful intercept, policy enforcement, and other service-provider features under functional and scale conditions.
• Validate CLI, YANG models, model-driven telemetry, gRPC/NETCONF/gNMI, and operational data required for managing and troubleshooting large cnBNG deployments.
• Debug sophisticated solution-level issues using IOS-XR logs, traces, telemetry, packet captures, core dumps, IXIA/Spirent statistics, and platform/NPU diagnostics.
• Perform detailed root-cause isolation, determining whether failures originate in the Control Plane, User Plane, forwarding infrastructure, Silicon One NPU, automation environment, traffic generator, or external network components.
• Partner closely with development, platform, system architecture, and customer-facing engineering teams to reproduce defects and drive them to closure.
• Define measurable test exit criteria and provide data-driven release-quality and readiness recommendations based on functional, scale, performance, and resiliency results.
• Use Git and modern software-development practices for automation code, test reviews, defect management, and CI/CD integration.
• Actively use approved AI coding assistants and engineering agents for automation development, test generation, log analysis, failure clustering, defect analysis, and troubleshooting while responsibly validating AI-generated output.
• Mentor junior engineers and help improve solution-testing methodology, automation architecture, scale infrastructure, and overall engineering quality.

Minimum Qualifications (Must-Have)

• Bachelor's or master's degree in Computer Science, Electrical/Computer Engineering,
• Telecommunications, or a related field. Strong experience in system, solution, scale, performance, and resiliency testing of networking products or carrier-grade networking solutions.
• Strong understanding of test methodologies covering functional, integration, system, regression, scale, performance, stress, longevity, failover, and high-availability testing.
• Hands-on expertise with Keysight IXIA and/or Spirent traffic-generation platforms, including
• protocol emulation, subscriber emulation, traffic generation, scale testing, and performance analysis.
• Strong Python programming and experience developing scalable test automation using pyATS/
• Genie or equivalent frameworks.
• Experience integrating automated test suites into CI/CD and continuous regression pipelines.
• Strong IP networking fundamentals, including L2/L3 forwarding, IPv4/IPv6, routing, MPLS/L3VPN, and QoS. Knowledge of broadband/subscriber technologies and protocols including PPPoE, IPoE, DHCPv4/v6, PPP, RADIUS/CoA, and L2TP.
• Experience configuring, validating, and solving IOS-XR or another carrier-grade network operating system.
• Ability to design and implement large-scale network topologies and systematically characterize capacity, throughput, latency, convergence, resource utilization, and failure recovery.
• Strong understanding of high availability, duplication, subscriber-state management, and fault- recovery mechanisms.
• Strong Linux skills and experience with Git, debugging tools, packet collections, logs, telemetry, and defect-management systems.
• Strong solving and analytical skills with the ability to isolate sophisticated issues across traffic generators, network protocols, software, hardware, and forwarding layers.
• AI-assisted engineering is a must: use of AI coding assistants such as GitHub Copilot and a working understanding of generative AI, AI agents, MCP (Model Context Protocol), reusable AI skills, prompt/context management, and responsible validation of AI-generated output, including AI-assisted log and defect analysis.

Preferred Qualifications

• Experience validating cnBNG, BNG, or broadband subscriber solutions.
• Experience with CUPS / Control Plane–User Plane separation and large-scale distributed User
• Plane deployments.
• Sophisticated experience with IXIA BreakingPoint/IxNetwork and/or Spirent Test Center, including automation APIs and large-scale subscriber/traffic emulation.
• Experience with Cisco 8000, ASR 9000, NCS 5500/5700, Silicon One, or comparable carrier-grade routing platforms and NPUs. Experience validating subscriber scale, session churn, traffic performance, convergence, and long-duration stability.
• Experience with SRG geo/warm excess, ISSU, NSR/NSF, and service continuity testing.
• Knowledge of SRv6/Segment Routing, MPLS, EVPN/VPLS, TE/GRE tunnels, BFD, BGP Flowspec, and ACLs. Experience with YANG, gRPC, NETCONF, gNMI, OpenConfig, and telemetry. Experience building automated performance dashboards, test-result analytics, failure classification, and regression trend analysis.
• Familiarity with Aha/Jira APIs engineering and defect-management integrations.

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. 

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