Test Engineers (IMS)

Senior IMS Test Engineer

Location: Hatfield, Hyrbid 3x a week on site. 

Technical Expertise & Capability Summary

IMS Core Network Expertise

• Strong working knowledge of IMS architecture and core network elements including CSCF, MTAS, SBG, BGF, IPSMGW, AFG, HPSYNC Server and SDIN
• Experience supporting and validating core network functionality within complex telecom environments

VoLTE / VoNR / VoWiFi Testing

• Proven expertise in VoLTE, VoNR and VoWiFi validation
• Strong understanding of 5G call flows, including registration, session management and handover procedures
• Experience validating voice services across LTE and 5G networks

Protocol & Interface Knowledge

• Solid understanding of SIP, SDP, MGCP, Diameter, RTP/RTCP and GTP protocols
• Experience working with Diameter interfaces including Cx, Dx, Ro and Rf
• Ability to analyse signalling flows and troubleshoot protocol-level issues

3GPP Standards & Compliance

• Good understanding of 3GPP specifications for LTE and 5G networks
• Experience ensuring solutions align with industry standards and compliance requirements

End-to-End (E2E) Testing

• Hands-on experience performing end-to-end testing across full call lifecycle scenarios
• Validation of registration, call setup, hold, resume, call waiting and conference call functionality
• Strong focus on service validation and customer-impact prevention

Nice to haves:

• RAN (Radio Access Network) knowledge