Senior Cs Core Network Engineer Jobs (NOW HIRING)

We are seeking a highly skilled Network Engineer to join our Core Network Engineering team. This is a senior-level, hands-on engineering position responsible for designing, deploying, scaling, and supporting FirstLight's carrier-class backbone network.

The ideal candidate will have strong experience with optical transport, DWDM, SONET, Carrier Ethernet, and IP/MPLS networking technologies and will lead network projects from concept through deployment and operational turnover.

Position Summary

The Core Network Engineer is responsible for the deployment, capacity expansion, security, troubleshooting, and operational support of FirstLight's production backbone network. This role combines network engineering, project leadership, capacity planning, and Tier 3 escalation support.

The successful candidate will lead network deployments from initial design through implementation, migration, testing, and operational acceptance. They will work closely with Operations, Service Delivery, Construction, Outside Plant, and vendor teams to ensure successful execution of network projects while maintaining the reliability and scalability of FirstLight's backbone infrastructure.

This position plays a critical role in the ongoing evolution of the network, including supporting growth initiatives involving the latest transport technologies.

Key Responsibilities

Network Engineering & Deployment

• Lead network deployments from planning and design through implementation, testing, migration, and operational handoff.
• Develop engineering designs, implementation plans, migration procedures, test plans, and rollback strategies.
• Own network expansion, augmentation, and modernization projects from start to finish.
• Ensure deployed solutions meet operational, scalability, resiliency, and performance requirements.
• Coordinate with internal teams and external vendors to ensure successful project execution.
• Design, deploy, and troubleshoot carrier-class optical transport networks.
• Engineer and scale DWDM infrastructure supporting backbone growth and service expansion.
• Engineer, design, and implement upgrades to the IP Core backbone.
• Plan and implement capacity upgrades supporting flex-grid transport technologies.
• Support optical path engineering, wavelength provisioning, network resilience, and transport optimization.
• Design, deploy, and troubleshoot large-scale Carrier Ethernet backbone networks.
• Maintain expert-level knowledge of Layer 2 transport technologies and Ethernet service architecture.
• Support Ethernet transport technologies
• Develop and maintain engineering standards and best practices.
• Design, deploy, and support carrier-grade IP/MPLS backbone infrastructure.
• Maintain strong expertise in MPLS and IP networking Protocols
• Support backbone routing, network resiliency, and service provider interconnection initiatives.
• Deploy, administer, and optimize Fortinet FortiGate and Cisco Firepower security solutions.
• Configure and maintain firewall policies, IPS/IDS, VPNs, NAT, application controls, and threat prevention services.
• Perform network security assessments, vulnerability remediation, and security hardening initiatives.

Capacity Planning & Network Growth

• Lead capacity planning initiatives across optical, transport, and routing platforms.
• Analyze utilization trends and forecast network growth requirements.
• Develop solutions for increasing network scale, performance, and resiliency.
• Support long-term technology roadmaps and network evolution strategies.
• Evaluate new technologies, hardware platforms, and software solutions.

Technical Leadership & Escalation Support

• Serve as a Tier 3 escalation resource for complex network issues and outages.
• Lead troubleshooting efforts across optical, DWDM, SONET, Ethernet, MPLS, and IP routing environments.
• Conduct root cause analysis and develop corrective actions for major network events.
• Work directly with vendors to resolve complex hardware, software, and interoperability issues.
• Mentor and support Operations and Engineering teams on network technologies and best practices.

Required Qualifications

• Bachelor's degree or equivalent in Engineering, Computer Science, Telecommunications, or equivalent experience.
• 7+ years of experience in service provider, telecommunications, carrier, or large-scale network engineering.
• Strong experience designing, deploying, and troubleshooting:
  • DWDM Transport Networks
  • Optical Transmission Systems
  • SONET Infrastructure
  • Carrier Ethernet Networks
  • IP/MPLS Networks
• Experience leading network deployment, migration, and infrastructure expansion projects.
• Strong troubleshooting skills across Layer 1, Layer 2, and Layer 3 technologies.
• Experience working in multi-vendor carrier network environments.
• Ability to develop implementation plans, migration procedures, testing methodologies, and operational documentation.
• Strong verbal and written communication skills.
• Must be a team player.

Preferred Qualifications

• Experience with carrier-grade platforms such as:
  • Ciena
  • Cisco
  • Juniper
  • Nokia
  • Adva
• Experience supporting large-scale optical and packet backbone networks.
• Experience with coherent optical technologies and modern transport architectures.
• Industry certifications such as:
  • CCNP / CCIE
  • JNCIP / JNCIE
  • MEF Certifications
  • CISSP
• Experience supporting networks utilizing 100G, 400G, and 800G+ transport technologies.

• Participation in a rotating on-call schedule is required.
• Must be available to support emergency outage restoration activities and critical network events outside normal business hours.
• Participation in scheduled maintenance windows and after-hours implementation activities is expected.
• Occasional travel may be required to support network deployments, central office builds, vendor engagements, and infrastructure projects.
• Ability to work in a fast-paced environment supporting a 24x7 carrier network.

About FirstLight:

FirstLight, headquartered in Albany, New York, provides fiber-optic data, Internet, data center, cloud and voice services to enterprise and carrier customers throughout the Northeast connecting more than 13,000 locations in service with more than 125,000 locations serviceable by our more than 25,000-route mile network. FirstLight offers a robust suite of advanced telecommunications products featuring a comprehensive portfolio of high bandwidth connectivity solutions including Ethernet, wavelength, and dark fiber services as well as dedicated Internet access solutions, data center, cloud and voice services. FirstLight’s clientele includes national cellular providers and wireline carriers and many leading enterprises, spanning high tech manufacturing and research, hospitals and healthcare, banking and financial, secondary education, colleges and universities, and local and state governments.

FirstLight Fiber is an equal opportunity employer. In accordance with state and federal laws, FirstLight’s equal opportunity policy is that all applicants and employees are treated equally by the company with respect to employment opportunities, regardless of race, color, religion, sex, sexual orientation, disability, or veteran status or veteran disability.