IMS Core Engineer

You will join the mobile core team and take ownership of our IMS mobile platform. You'll manage networks and nodes across our 2.5G, 3G, and 4G environments, working with SIP, H323, IMS/IMT, VoLTE, and VoWiFi technologies. You'll use dashboards, building new ones where needed, to quickly spot issues and patterns. When incidents arise, you'll follow established communication procedures both internally and with third-party providers. You'll handle maintenance, troubleshooting, security audits, and emergency response, undertaking fault handling and corrective actions at the node, service, and infrastructure level. You'll take part in project work, implementing and adapting new IMS end-to-end service functionalities, nodes, and services. From time to time, you'll cover 7x24 monitoring shifts, including on-call support and baby-sitting activities. You'll use Wireshark tracing on critical infrastructure to debug issues, provide input on process improvements, and verify and implement configuration changes.

Responsibilities

• Manage networks and nodes within the IMS domain for 2.5G, 3G & 4G networks (SIP, H323, IMS/IMT, VoLTE, VoWiFi)
• Build and use dashboards to discover issues and patterns
• Follow communication procedures when handling incidents internally and with third-party providers
• Perform maintenance, troubleshooting, security audits, and emergency response
• Undertake fault handling and corrective actions on node, service and infrastructure level
• Handle project activities implementing and adapting new IMS E2E service functionalities, nodes, and services
• Cover 7x24 monitoring shift responsibilities including on-call support and baby-sitting activities
• Perform Wireshark tracing of critical infrastructure to debug issues
• Provide input, implement and verify improvements in processes and work instructions
• Verify and implement configuration changes
• Identify and drive improvements

Requirements

• At least 10 years' experience in the core network domain with mobile networks
• BSc degree in Telecommunication or Computer Science (post-graduate studies are a bonus) and 10+ years core telecommunications network experience
• Working knowledge of telecom networks like 2G, 2.5G, 3G and LTE (MME, SGW, PGW, and MME)
• Conceptual understanding of IMS evolution and trends - IMS Subsystems, functionalities and IMS services call flows
• Knowledge of IMS network topology, Core IMS Parameters and Features
• Experience with different types of Core Nodes, CSFB, IMS (P-CSCF, I-CSCF, S-CSCF, MTAS, HSS, CUDB, MGCF, etc.)
• Experience with SS7, ISUP, BICC, SIP, H248, Diameter signaling & protocols configuration change for IMS based services
• Experience with operation and maintenance of IMS platforms for alarms, faults/abnormal conditions handling, trace analysis, troubleshooting, system backup/restore, fault diagnostics, preventive maintenance & upgrades
• Experience with configuration preparation & implementation for IMS nodes and integration for all nodes (S-CSCF, I-CSCF, MTAS, HSS, CUDB, etc.)
• Hands on experience with sniffers, Wireshark and testing tools in advanced mode
• Hands on experience with Linux/Unix based systems
• Understanding of 3GPP, ITU-T and ANSI standards
• Understanding of roaming agreements and IR.21, including IREG testing
• Experience with VoLTE troubleshooting and call trace analysis
• Strong writing and documentation skills
• Fluent in English (written and spoken)
• Willingness to work on morning/afternoon shifts
• 2+ years scripting experience (Python, Bash, etc.) - nice to have