IMS Component Test Engineer (m/f/d)

ng-voice GmbH; Hamburg; Hybrid; EUR 50.000 - 70.000; Vollzeit

Zusammenfassung

A technology company in Hamburg is looking for an IMS Component Test Engineer to design and execute tests for IMS network components. You will focus on protocol validation and load behavior, utilizing SIPp for testing and Kubernetes for deployment. Ideal candidates will exhibit strong skills in IMS call flows and load testing, with a commitment to enhancing system robustness and efficiency. The role offers a flexible working environment and opportunities for professional growth.

Leistungen

Flexible working arrangements

Mobility benefit

Fitness benefit

Language class benefit

Wellness benefit

Home office budget

Qualifikationen

• Strong understanding of IMS protocol-level validation and testing.
• Experience with SIPp-based testing and load emulation.
• Ability to analyze and troubleshoot mixed-protocol call flows.

Aufgaben

• Design and execute isolated testing of IMS network components.
• Provide insights for improving IMS robustness and efficiency.
• Monitor IMS performance and analyze resource utilization.

Kenntnisse

Understanding of 3GPP IMS call flows

Knowledge of timers, retransmissions, and failure scenarios

Familiarity with ENUM / DNS / NAPTR in IMS routing

Basic Kubernetes troubleshooting

Awareness of how container limits affect SIP/Diameter performance

Tools

SIPp

Grafana

Kubernetes

Jobbeschreibung

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)