IMS Component Test Engineer (m/f/d)

Permanent employee, Full-time · Hamburg

About us

Role Overview

We are looking for an IMS Component Test Engineer to design, execute, and optimize isolated testing of individual IMS network components such as P-CSCF, S-CSCF, I-CSCF, and IMS Application Servers.

The role focuses on protocol-level validation, load behavior, and resource efficiency, using SIPp-based SIP emulation and Diameter emulators to simulate dependent IMS interactors. All IMS components are containerised and deployed on Kubernetes.

The engineer will work closely with platform, core network, and performance teams to ensure each IMS component behaves correctly, efficiently, and predictably under both functional and stress conditions.

Tasks

Key Responsibilities

IMS Protocol & Call Flow Testing

Perform individual component-level testing of IMS elements (P-CSCF, S-CSCF, AS, etc.) in isolation
Provide actionable insights to improve IMS robustness, scalability, and efficiency
Analyze and troubleshoot SIP, Diameter, and mixed-protocol call flows

SIPp-Based Emulation & Load Testing

Design and maintain SIPp XML scenario files for IMS signaling use cases
Correlation between multiple SIPp scripts to keep traffic realistic for the system under test
Create input CSV files and dynamic data injection for large subscriber sets
Emulate IMS interactors using SIPp (UEs, proxies, application servers)
Execute bulk-load, CPS, and long-duration endurance tests
Model real world traffic on individual IMS components from Wireshark captures
Capture, inspect, and analyze pcaps for SIP signaling validation

Observability & Resource Analysis

Monitor IMS component performance using Grafana dashboards
Analyze:
- CPU, memory, network, and socket utilization
- Max traffic capacity
- Latency under load
Correlate protocol-level behavior with resource consumption
Identify bottlenecks, leaks, or inefficiencies during prolonged runs

Requirements

Valuable Skills

These skills will significantly improve the effectiveness of individual IMS component testing:

IMS & Telecom-Specific

Understanding of 3GPP IMS call flows
Knowledge of timers, retransmissions, and failure scenarios
Familiarity with ENUM / DNS / NAPTR in IMS routing
Exposure to Kamailio / OpenSIPS

Kubernetes & Platform Awareness

Basic Kubernetes troubleshooting
Awareness of how container limits affect SIP/Diameter performance

Benefits

A little more about our culture and why you should join

Work-Life-Balance is a priority: Flexible working that suits you - we live and breathe a hybrid remote culture and don't mind where and when you work
We are committed to building a diverse team that represents a variety of backgrounds, perspectives, and skills in a traditionally not very diverse industry
We offer you the culture of a fast-growing start-up with the maturity of an enterprise company
We are more interested in your experience and knowledge than formal degrees
Entrepreneurial culture and flat hierarchies
Mobility benefit, fitness benefit, language class benefit and wellness benefit (for full-time employees)
Home office budget (for full-time employees)

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About us

ng-voice is an equal opportunity employer. We believe demographic characteristics and diverse experiences that have nurtured unique viewpoints benefit our growth and performance and value each person and their different background as a whole.

Hope we caught your attention; we look forward to getting to know you!

DISCLAIMER

Even if you do not meet 100% of the requirements, however, you think this role will be a good match for you, please send in your application. We would love to be in touch!

Please be aware that we are currently not collaborating with agencies and any profile received will not be taken into consideration.

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We are looking forward to hearing from you!

Thank you for your interest in ng-voice. Please fill out the following short form. Should you have difficulties with the upload of your data, please send an email to jobs@ng-voice.com.