Network Engineer III

The Network Engineer III is a senior-level engineering role responsible for high-complexity network troubleshooting, system design, capacity planning, and advanced diagnostics. This position acts as an escalation point for Network Engineer I & II and works closely with the Senior Network Architect on architectural improvements, security enhancements, and major infrastructure projects. The Network Engineer III plays a key role in ensuring stability, scalability, and performance across fiber and wireless networks., The essential functions include, but are not limited to the following:

• Design, configure, and operate the Juniper (Junos) routed core and aggregation: IS-IS, BGP, MPLS (LDP/RSVP), L2VPN/L3VPN, and EVPN-VXLAN/EVPN-MPLS across the core and PE edges.
• Own access-layer engineering on Calix AXOS (E7/E9, GPON/XGS-PON) including dual-PE designs and DHCP relay.
• Performs advanced diagnostics across multiple OSI layers, identifying root causes of service-impacting or chronic issues.
• Design and troubleshoot G.8032-protected access rings and backhauls.
• Leads troubleshooting for escalated fiber, wireless, routing, firewall, and security issues across service areas.
• Conducts capacity planning and analyzes network growth trends to support future expansions.
• Perform and/or guide advanced testing such as OTDR analysis, optical budget validation, RF spectrum analysis, and transport signal integrity.[A1] [A2]
• Evaluates and implements network improvements to enhance reliability, redundancy, and performance.
• Develops and enforces engineering standards, configuration templates, and security policies.
• Works closely with the NOC on outage resolution, root cause analysis, and post-incident reviews.
• Leads engineering support for new builds, upgrades, ring designs, backhaul improvements, and architecture migrations.
• Collaborates with vendors on complex support cases, platform bugs, or feature requests.
• Creates advanced documentation, engineering diagrams, and SOPs for operational teams.
• Mentors Network Engineer I and II team members, providing guidance on troubleshooting and design principles.
• Acts as a technical subject matter expert for cross-functional teams and leadership., * Remote work environment with occasional travel to company office locations as business needs require.
• May require occasional on-site work in headend/CO environments or equipment rooms.
• Participates in a shared on-call rotation and in after-hours maintenance windows, major cutovers, and outage response.
• High-complexity engineering environment requiring deep technical focus.

• Bachelor’s degree or equivalent technical experience.
• 4-7 years of experience in network engineering, ISP operations, or telecom environments.
• Certs: JNCIP-SP / JNCIE-SP strongly preferred; CCNP/other vendor certs a plus.

Knowledge & Skills

• Expert-level Juniper Junos on MX/QFX-class platforms (required).
• Deep operational knowledge of IS-IS, BGP, MPLS, EVPN-VXLAN, VRF, QoS and advanced routing/switching.
• Familiarity with G.8032, CG-NAT (NetElastic a plus), and IRR/RPKI routing hygiene.
• Strong security understanding including firewall architecture, VPNs, AAA, IDS/IPS, and segmentation.
• Lead complex troubleshooting efforts and interpret advanced diagnostic data.
• Strong documentation, leadership, and communication skills.
• Scripting/automation (Python or PowerShell) and infrastructure-as-source-of-truth (NetBox) discipline.

Physical Demands and Work Environment

The physical demands described here are representative of those that must be met by an employee to successfully perform the essential functions of this position. Reasonable accommodations may be made to enable individuals with disabilities to perform the functions.

Physical Demands

• Prolonged periods of working at a computer.
• Occasional lifting of equipment up to 70 lbs.
• Travel to remote network sites across multiple states, including rural locations. A valid driver’s license is required.

Pulled from the full job description

• 401(k)
• Health insurance
• Paid time off
• Employee discount
• Vision insurance
• Dental insurance
• Life insurance, * 401(k)
• Dental insurance
• Employee discount
• Health insurance
• Life insurance
• Paid time off
• Vision insurance

Core Fiber is a growing telecommunications company dedicated to delivering reliable, high-speed internet and connectivity solutions to the communities we serve. Through our family of regional brands, we focus on building strong local relationships while providing the technology and infrastructure customers depend on every day.

We operate across multiple states, bringing fiber-forward innovation, dependable service, and customer-focused support to residential and business clients alike. Our team is committed to expanding broadband access, improving network performance, and ensuring our customers stay connected to what matters most.

At Core Fiber, we believe our people are the foundation of our success. We foster a culture built on accountability, collaboration, and continuous improvement. Whether in the field, supporting customers, or driving strategy behind the scenes, every team member plays a vital role in delivering exceptional service and strengthening the communities we serve.

If you’re looking to grow your career in a fast-paced, evolving industry where your work makes a real impact, Core Fiber may be the right place for you.