IMS Test Engineer (NOKIA, CSCF, HSS, AS, SBC), ONSITE COPENHAGEN

IMS Test Engineer (NOKIA, CSCF, HSS, AS, SBC), ONSITE COPENHAGEN

EU Passport needed

Location: Copenhagen (ONSITE = EU Passport needed)
Start: ASAP
Duration: 6 months +

For our Danish client we need a Nokia skilled - IMS Test Engineer, ONSITE in Copenhagen

New Nokia Core 5G to be installed, in an existing network

Role Description:

• Validate subscriber provisioning, registration, authentication, and service profile management within IMS core elements (CSCF, HSS, AS, SBC).
• Validate end-to-end service assurance for IMS-based services such as VoLTE, VoWiFi, SMS over IP, emergency calls, and supplementary services.
• Perform IMS attach/registration/deregistration testing, verify SIP signalling flows, and confirm correct IMSI/MSISDN/IMPU/IMPI mapping and subscriber profile assignment.
• Test mobility scenarios including SRVCC, handover between LTE/5G and Wi-Fi, ensuring seamless service continuity.
• Ensure realistic and comprehensive test data for subscriber provisioning, service triggers, and policy enforcement within IMS.
• Test integration between IMS core and other network elements: HSS/UDR, PCRF/PCF, OCS, SBC, MGCF, MSC-S, emergency routing platforms, billing, CRM, and provisioning systems.
• Conduct regression testing to ensure that new releases, updates, or patches to IMS nodes (CSCFs, AS, SBC) and OSS/BSS do not impact existing VoLTE/VoWiFi functionalities.
• Validate Call Detail Record (CDR/EDR) generation for SIP sessions, voice/video calls, messaging, supplementary services, and roaming scenarios.
• Validate prepaid/postpaid charging events, policy enforcement, and online credit control mechanisms for IMS services.
• Ensure seamless communication between IMS core network elements and business applications, including lawful intercept and emergency services.
• Conduct performance, stress, and load testing on IMS nodes (CSCFs, SBCs, AS) and related OSS/BSS systems.
• Monitor and analyse latency, call setup times, throughput, failover, and high-availability scenarios within IMS.
• Implement test automation frameworks (SIP call generation, VoLTE/VoWiFi scenarios) to streamline validation, ensuring efficient, scalable, and repeatable IMS testing processes.
• Log, track, and prioritise defects using JIRA (or equivalent test management tools).
• Work closely with IMS developers, EPC/5GC teams, and operations to resolve issues.
• Provide test reports, KPIs, and recommendations for system enhancements.
• Strong understanding of IMS and mobile core architecture, including CSCF, HSS/UDR, AS, SBC, PCRF/PCF, OCS, MGCF, MSC-S, VoLTE, VoWiFi, SRVCC, and 5G/IMS interworking.

Skills & Tools (Competencies)
Core Technical Skills

• In-depth knowledge of IMS protocols: SIP, Diameter (Cx, Sh, Ro, Rx, Gx), RTP/RTCP, ENUM, DNS.
• Strong understanding of VoLTE/VoWiFi call flows, SRVCC, emergency call handling, roaming scenarios, and 5G/IMS interworking.
• Familiarity with charging and policy control: OCS/CHF, PCRF/PCF, online/offline charging flows.
• Experience with test automation for IMS/VoLTE (Python, Robot Framework, Spirent, Ixia, SIPp).
• Testing & Analysis Tools
• SIP signalling tools: Wireshark, sngrep, SIPp, Call Flow analyzers.
• Load/performance test tools: Spirent Landslide, Keysight IxLoad, or equivalent.
• Test case management and defect tracking: JIRA, TestRail, HP ALM.
• CDR/EDR verification: SQL, ElasticSearch, or similar tools to parse records.
• Operational Competencies
• Ability to support, clarify and maintain test plans, scripts, and KPIs for IMS services.
• Hands-on experience with network traces and troubleshooting across EPC/5GC and IMS.
• Awareness of security and lawful intercept requirements for IMS services.
• Understanding of OSS/BSS integration: CRM, provisioning, billing.

Soft Skills

• Strong collaboration with cross-functional teams (Core Network teams, Operations, IT-BSS, Nokia).
• Clear documentation and reporting for technical and non-technical stakeholders.
• Problem-solving and analytical mindset to isolate and resolve IMS issues quickly