Senior Core Network Engineer

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, N3IWF4G EPC:MME, SGW, PGW, HSS, PCRF, DRA/DEAIMS and voice: P-CSCF, I-CSCF, S-CSCF, TAS, MRF, BGCF, MGCF, VoLTE, VoWiFiNon-3GPP access:ePDGRoaming and interconnect: GTP Proxy, DEA, SEPP, IPX/GRX, Diameter–MAP interworking Legacy 2G/3G:HLR/AuC, MSC/VLR, SGSN, GGSN, STP, EIR, CAMELMessaging and charging: SMSC, SMSF, OCS/OFCSProtocols: Diameter, GTP-C/GTP-U, SIP, SS7/SIGTRAN, MAP, HTTP/2-based SBI,

PFCPKey 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.

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 environmentCCN 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: HR@cirruscorenetworks.com.