Senior Core Network Engineer

Cirrus Core Networks, Inc.; Northern (KY); Hybrid; USD 150,000 - 190,000; Full time

Job summary

Cirrus Core Networks, Inc. is seeking a Senior Core Network Engineer (Escalation & Operations Lead) to act as the final technical escalation point for Sev-1 incidents and critical outages.

The role leads complex multi-vendor core deployments from planning through handover, conducts root-cause analysis, and coordinates with NOC and Operations teams to ensure reliable service. The candidate will manage complex troubleshooting across 5G SA, 4G EPC, roaming, and legacy networks, mentoring junior

Qualifications

• 7+ years in mobile core operations or engineering
• Proven experience leading mobile core deployments or migrations in production
• Direct experience with Sev-1 incident resolution and root cause analysis
• Hands-on experience with 4G EPC and IMS functions (HSS, PCRF, DRA, packet core)
• Knowledge of 2G/3G cores (HLR/MSC/VLR/SS7) and cross-generation troubleshooting
• Strong multi-vendor troubleshooting across Diameter, GTP, SIP, SS7/SIGTRAN
• Calm, clear communication during high-pressure incidents with teams and customers

Responsibilities

• Serve as final escalation point for Sev-1 and outages across the core network scope
• Lead root cause analysis and drive corrective actions
• Troubleshoot complex multi-vendor, multi-protocol issues including roaming failures
• Lead end-to-end core deployments: planning, testing, cutover, and handover to ops
• Coordinate with vendors, internal teams, and customers during deployments
• Mentor NOC engineers and develop runbooks and docs

Skills

Sev-1 incident management

Multi-vendor deployments

Diameter/GTP/SIP/SS7 troubleshooting

4G EPC/IMS operations

Virtualized/Containerized NF

Clear communication under pressure

Roaming/interconnect knowledge

Legacy 2G/3G core knowledge

Tools

NFV platforms

Job description

Senior Core Network Engineer (Escalation & Operations Lead)

US or Europe (Remote)

Details

Position

Senior Core Network Engineer (Escalation & Operations Lead)

Location

Remote

Job Type

Full Time / Contract

Positions Available

One

Description

About CCN

Cirrus Core Networks is a US-based telecom core network operator and managed services provider serving MVNOs and MNOs.

Role Summary

The Senior Core Network Engineer is CCN’s final technical escalation point for critical incidents across the mobile core. The role leads core network deployments from planning through handover, as well as root cause analysis, complex troubleshooting, performance tuning, and migration execution. It also serves as the senior technical bridge to CCN’s distributed NOC and Operations teams.

• 5G SA core: AMF, SMF, UPF, UDM, UDR, AUSF, PCF, NRF, NSSF, NEF, SEPP, BSF, CHF, N3IWF
• 4G EPC: MME, SGW, PGW, HSS, PCRF, DRA/DEA
• IMS and voice: P-CSCF, I-CSCF, S-CSCF, TAS, MRF, BGCF, MGCF, VoLTE, VoWiFi
• Non-3GPP access: ePDG
• Roaming and interconnect: GTP Proxy, DEA, SEPP, IPX/GRX, Diameter–MAP interworking
• Legacy 2G/3G: HLR/AuC, MSC/VLR, SGSN, GGSN, STP, EIR, CAMEL
• Messaging and charging: SMSC, SMSF, OCS/OFCS
• Protocols: Diameter, GTP-C/GTP-U, SIP, SS7/SIGTRAN, MAP, HTTP/2-based SBI, PFCP

Key Responsibilities

• Serve as final technical escalation point for Sev-1 and critical outages across the technology scope above.
• Lead root cause analysis and drive corrective actions to closure.
• Troubleshoot complex multi-vendor, multi-protocol issues, including cross-generation interworking and roaming failures.

Deployment Leadership & Operations

• Lead core network deployments end to end, including planning, implementation, testing, cutover, and handover to operations, in line with approved architecture.
• Coordinate vendors, internal teams, and customer technical contacts throughout deployment.
• Lead platform migrations and cutovers.
• Own performance tuning and capacity monitoring for production platforms.
• Produce low-level designs and implementation plans.
• Plan and run vendor solution validation and acceptance testing, in coordination with the Senior Core Network Architect and Product Management.
• Manage technical escalations with vendors through to resolution.

Team Enablement

• Mentor NOC engineers and raise escalation capability across CCN’s distributed operations teams.
• Develop and maintain troubleshooting runbooks and operational documentation.

Qualifications

Required Qualifications

• 7+ years of hands-on mobile core operations or engineering in a production environment
• Proven experience leading mobile core deployments or migrations in a production operator or managed services environment
• Direct experience leading Sev-1 incident resolution and formal root cause analysis
• Hands-on experience operating 4G EPC and IMS functions, including HSS, PCRF, DRA, and packet core
• Working knowledge of legacy 2G/3G core networks (HLR, MSC/VLR, SGSN/GGSN, SS7/MAP) and troubleshooting across network generations
• Strong troubleshooting across Diameter, GTP, SIP, and SS7/SIGTRAN, including protocol trace analysis
• Experience operating virtualized or containerized network functions
• Clear, calm communication during high-pressure incidents with internal teams, customers, and vendors

Preferred Qualifications

• 5G SA core exposure, including service-based interface troubleshooting
• Experience operating GTP Proxy, ePDG, or roaming interconnect platforms
• Experience working with distributed, multi-region NOC and Operations teams
• Experience in a managed services or MVNO/MNO operator environment

CCN offers a competitive compensation package that reflects the scope and seniority of this role, the candidate’s experience, and local market rates. Because this role is open to candidates in the US and Europe, compensation and benefits will vary by country and will be structured in line with local market practice and employment requirements. Details will be discussed with candidates during the interview process.

Cirrus Core Networks is an equal opportunity employer. We are committed to building a diverse, inclusive team and do not discriminate on the basis of race, color, religion, sex, pregnancy, sexual orientation, gender identity or expression, national origin, age, disability, genetic information, veteran status, or any other characteristic protected by applicable law in the country where the role is based. Employment decisions are based on qualifications, merit, and business needs. If you need an accommodation during the application or interview process, please contact: [e-mail].