Core PS / IP Engineer

Responsible for the operation, maintenance, troubleshooting and optimization of Mobile Core PS and IP infrastructure, including legacy EPC and next-generation virtualized and cloud-based Core platforms.
The role contributes to the introduction, integration and evolution of NFVI, 5G NSA/SA and 5G Core technologies, as well as to the interworking of PS, CS and IMS domains, ensuring the reliable operation of end-to-end mobile services.

Key Responsibilities:
1. Core PS & IP Network Operations

• Operate, monitor and maintain Core PS network elements and related IP infrastructure, including virtualized/NFVI platforms.
• Monitor network availability, performance, capacity and key operational KPIs.
• Identify potential performance and capacity issues and contribute to network optimization.

2. Troubleshooting & Network Analysis

• Troubleshoot issues related to mobile data, APN, session establishment, mobility, authentication, DNS and IP connectivity.
• Analyze GTP, Diameter and IP traffic using packet captures, logs and network monitoring tools.
• Investigate and resolve IP connectivity and routing issues, including BGP, VLAN, VRF, NAT and ACL related problems.
• Perform root-cause analysis and provide effective solutions for service-impacting incidents.

3. 5G, NFVI & Network Transformation

• Support the introduction, integration and stabilization of 5G NSA/SA and next-generation Core technologies.
• Participate in NFVI deployments, migrations, software upgrades and network modernization projects.
• Support the evolution towards virtualized and cloud-native Core environments.
• Contribute to testing, integration and troubleshooting during network transformation projects.

4. Roaming & Interworking

• Support roaming services and troubleshoot issues in cooperation with internal teams and roaming partners.
• Support troubleshooting of PS/CS/IMS interworking issues related to VoLTE, voice, SMS and other IMS-based services.

5. Technical Collaboration

• Work closely with internal technical teams, vendors and technology partners to investigate and resolve complex network issues.
• Participate in incident resolution, technical investigations and network improvement initiatives.
• Contribute to technical documentation and knowledge sharing within the team.

Required Knowledge & Experience:

• Bachelor's degree in Telecommunications, IT, Computer Science or a related field.
• 3–5 years of relevant experience in Mobile Core, Packet Core and/or IP networks.
• Solid understanding of LTE/EPC architecture and good knowledge of 5G NSA/SA concepts.
• Good knowledge of GTP-C/GTP-U, Diameter, TCP/IP and DNS.
• Good understanding of IPv4/IPv6, routing, BGP, VLAN, VRF, NAT and ACL.
• Practical experience with Wireshark/Tshark, packet capture analysis, network monitoring and log analysis.
• Good knowledge of Linux/Unix CLI.
• Understanding of NFVI, virtualization and cloud-based/cloud-native Core environments.
• Basic understanding of CS Core and IMS/VoLTE service flows, including voice and SMS interworking.
• Good technical English and the ability to communicate effectively with vendors and internal technical teams.

Will Be an Advantage:

• Experience with Ericsson, Huawei or other Mobile Core solutions.
• Practical experience with NFVI, 5G Core, virtualized network functions and/or cloud-native platforms.
• Knowledge of CS Core, VAS and IMS/VoLTE, including voice, SMS, USSD and signaling flows.
• Experience with Diameter-based services related to IMS/VoLTE.
• Knowledge of Kubernetes and/or OpenStack.
• Basic Python and/or Bash scripting skills.
• Experience with network migrations, upgrades and technology transformation projects.

Key Competencies:

• Strong analytical and troubleshooting skills.
• Systematic and structured approach to problem solving.
• Strong sense of ownership and accountability.
• Ability to work effectively under pressure, especially during service-impacting incidents.
• Teamwork and cross-functional collaboration.
• Clear and effective technical communication.
• Ability to learn and adapt to new technologies.
• Proactive approach to network optimization and continuous improvement.