Job Summary

Job Description: 5GC L3 Operation Engineer (Contractor)

Position Information

Department: Core Network Operations Department

Section: Packet Core Operations Section / Core Operations Governance Section

Group: TBD(L4) / Core Quality & Capacity Management Group

Contract Type: Independent Contractor (Quasi-Mandate Agreement)

Working Style: Daytime support during RMI/RSI business days, with off-hours work (including nights, weekends, and holidays) only upon explicit instruction from RMI/RSI via email, message, or other clear communication.

2. Mission

To maximize the availability and reliability of the 5GC network by providing high-level L3 technical support, leading rapid incident resolution, conducting root cause analysis, driving L1/L2 technical development through OJT, and facilitating operational automation.

Key Responsibilities

3. Key Deliverables & Responsibilities

Incident Resolution & RCA: Provide advanced technical analysis for complex incidents within the 5GC network and lead root cause identification.

Deliverables: Timesheet.

Deliverables: Incident analysis reports, Root Cause Analysis (RCA) reports.

Vendor Technical Liaison: Collaborate with VNF/CNF vendors to discuss technical issues, validate bug fixes, and ensure the implementation of permanent solutions.

Deliverables: Technical inquiry records, patch validation reports.

Knowledge Transfer (KT) & OJT: Conduct On-the-Job Training (OJT) for L1/L2 engineers through real-world incident handling and operational tasks to enhance their technical capabilities.

Deliverables: OJT records, training materials, technical knowledge base (KB) documentation, Q&A repositories.

Operational Optimization & Automation Support: Propose improvements for operational procedures and monitoring processes based on troubleshooting insights and provide technical assistance for operational automation.

Deliverables: Updated operational procedures, KB documentation, technical proposals/implementation support for automation tools and scripts.

Skill Requirements

4. Required Qualifications

Experienced years：

10+ years’ experience in telecom industries including 5+ years NOC operations or 2+ years NOC management in Packet Core domain.

Other Requirements

Technical Expertise:

Deep knowledge of 5G Core (AMF, SMF, UPF
, etc.), 4G Core (MME, CUPS, SGW, PGW) and SGi (NAT, DPI: Deep Packet Inspection) design and operations.

Proven experience in operating and troubleshooting container platform environments using Kubernetes.

Experience in operations and maintenance of container-based network platforms in large-scale telecommunications environments.

Strong protocol-level analysis skills using packet analysis tools (e.g., Wireshark, Tcpdump).

Experience:

Proven track record as an L3 Support Engineer or Subject Matter Expert (SME) in large-scale telecommunications networks.

Demonstrated experience in technical mentoring and training (e.g., OJT, knowledge transfer).

Language & Soft Skills:

Fluent in English, capable of conducting technical negotiations with global vendors. Japanese language capability is not mandated.

Professional mindset with the ability to remain calm, autonomous, and decisive during high-pressure incident response situations.

5. Preferred Qualifications

Experience in performance optimization and tuning for large-scale traffic environments.

6. Workload & Operational Scale (For Accurate Staffing Estimates)

The current JD should be interpreted as daytime support during RMI business days with a baseline staffing assumption of 3 personnel. Vendors should base their proposal on this scope, while allowing exception-based off-hours support only upon explicit instruction from RMI.

• Scale of Managed Environment: 
  
  

• Please, note that traffic part is confidential.
• Number of CNFs: AMF, SMF (nodes count will be expanded with customer demands
• Traffic volume (4G/5G NSA): no traffic as on today, 4G complete traffic will be shifted gradually from existing components from August onwards.
• Traffic volume (5G SA): 5GC launch will be planned on Q4 2026.

Ticket volume: 10 tickets per month is expected against the product suppliers those are taken by L2.