Freelance Python Network Programming Jobs in Arlington Heights, IL

***We are unable to sponsor for this permanent full-time role***

***Position is bonus eligible***

Prestigious Financial Institution is currently seeking a Principal Cisco Network Engineer with strong Cisco and Multicast experience. Candidate will be responsible forshaping the design, scalability, and long-term evolution of highly distributed, latency-sensitive trading networks across on-prem and cloud environments. The Principal Engineer brings expert-level knowledge of deterministic packetforwarding, advanced routing design, and ultra-low latency architecture, combined with the ability tooperateindependently and own complex problems end-to-end. 

This individual partners closely with Network Engineering leadership and cross-functional architecture teams to lead high-complexity initiatives, conduct rigorous pre-implementation testing and validation, andestablishbest practices that drive consistency and reliability across the environment. They function as a technical leader without formal authority—mentoring senior engineers, influencing design decisions, and raising the overall engineering bar across the organization. 

Success in this role requires both deep technicalexpertiseandstrong communicationskills. The Principal Engineer must be able to translate complex architectural decisions, trade-offs, and risks into clear, actionable insights for both engineering teams and senior leadership. The ideal candidate holds (or is actively pursuing) a CCIE certification, writes production-quality Python, and is comfortable working with modern observability platforms such as Prometheus and Grafana to drive data-informed engineering decisions. 

Responsibilities:

• Design and evolve low-latency, highly resilient network architecture across global data center, co-location, and cloud-connected environments, with a focus on deterministic packetforwarding, scalability, and operational consistency 

• Lead advanced routing design and implementation across complex global environments, including BGP, OSPF, MPLS, multicast, hybrid cloud connectivity, traffic engineering, and high-availability network patterns 

• Conduct deep technical research, lab validation, and pre-implementation testing for major network initiatives, working closely with engineering and software development teams to evaluate hardware capabilities,identifydesign constraints, and optimize exchange performance based on findings 

• Lead high-complexity strategic projects from design through execution, producing detailed technical designs, migration runbooks, capacity plans, and implementation guidance for large-scale network changes 

• Develop andmaintainPython-based network automation to support configuration management, change validation, testing, and operational efficiency, with direct experience using both API-driven and SSH-based automation approaches 

• Partner across infrastructure, security, application, and business teams to align network design and delivery with technical requirements, operational goals, and broader organizational priorities, including support for budgeting and planning related to network hardware and software investments 

• Serve as a senior technical leader and mentor across the engineering organization, driving architecture reviews, design standards, knowledge sharing, and technical development for other engineers 

• Operate effectively in a fast-moving, dynamic environment where priorities can shift, balancing long-term architectural direction with immediate engineering and operational needs 

• Contribute to monitoring and telemetry strategy by helping define meaningful visibility requirements and supporting the use of tools such as Prometheus, Grafana, or similar platforms where they improve operational insight and troubleshooting 
• Support the development of technical standards, design documentation, and regulatory or audit-facing materials when needed, including documentation that may be used to support SEC or other regulatory review processes 

Qualifications:

• 10+ years of hands-on network engineering experience in mission-critical, low-latency environments, with a strongtrack recordoperating and evolving high-performance network infrastructure 

• Deepexpertisein low-latency and deterministic network design, including practical experience analyzing latency, jitter, and end-to-end traffic behavior in production environments 

• Advanced knowledge of routing protocols at scale, including BGP, OSPF, MPLS, and multicast (PIM-SM/SSM), with proven experience designing resilient,highly availableglobal networks 

• Strong understanding of network hardware and platform capabilities across major vendors, with the ability to evaluate limitations and optimize design decisions through hands-on research and lab validation 

• Experience designing and supporting hybrid cloud connectivity, including AWS networking constructs such as Direct Connect, Transit Gateway, VPCs, and route integration 

• Proven experience building andmaintainingPython-based network automation, including API-driven and SSH-based approaches for configuration management, testing, and operational efficiency 

• Working knowledge of observability and telemetry concepts, with exposure to platforms such as Prometheus, Grafana, or similar tools for network visibility and performance analysis 

• Strong background in leading technical research, proof-of-concept validation, and pre-implementation design for large-scale network initiatives 

• Solid understanding of network security fundamentals, including segmentation, access control, and zero-trust principles as they apply to network design 

• Experienceoperatingin fast-paced, highly dynamic environments, with the ability to adapt to changing priorities whilemaintaininga strong focus on execution and delivery 

• Demonstrated ability to mentor engineers, influence technical direction, and contribute to engineering standards and best practices across an organization 
• Experience contributing to technical documentation, design standards, or materials supporting regulatory or audit processes is a plus 

Preferred certifications: 

• Cisco CCIE (Routing & Switching or Data Center) or near-equivalent experience 

• AWS Advanced Networking Specialty or similar 

• Arista, Juniper, or other advanced vendor certifications