Senior SIP Performance Test Engineer

We are looking for a skilled SIP Performance and Validation Engineer to join our team responsible for ensuring the reliability, scalability, and high performance of our SIP-based communication platforms. You will lead performance testing using Spirent Landslide and SIPp, while performing in-depth analysis to identify bottlenecks and drive optimization recommendations. What we are looking for in the candidate
performance-driven engineer who loves pushing systems to the limit.
Strong analytical mindset with excellent problem-solving skills.
Ability to clearly communicate technical findings and recommendations.
Self-motivated and detail-oriented.

Responsibilities
Design, develop, and execute comprehensive SIP performance and scalability test plans using Spirent Landslide and SIPp to simulate high-volume call traffic, registration storms, and complex signaling scenarios.
Create and maintain custom SIPp scenarios (XML) for various test cases including basic calls, INVITE floods, REGISTER storms, SUBSCRIBE/NOTIFY, and failure scenarios.
Exercise and validate the SIP stack under load, measuring key metrics such as CPS (Calls Per Second), concurrent sessions, latency, packet loss, and error rates.
Perform deep-dive network and protocol analysis using tcpdump, Wireshark, and other packet capture tools.
Identify performance bottlenecks in SIP infrastructure components and provide clear, data-driven recommendations for optimization.
Develop automation scripts using Python and Bash to orchestrate testing, parse results, generate reports, and integrate with CI/CD pipelines.
Build and maintain automated test frameworks for repeatable performance validation.
Document test results, create detailed performance reports, and present findings to technical and leadership audiences.
Support production troubleshooting by analyzing live traffic captures.

Qualifications
Strong Networking Background:
Deep understanding of IP networking, TCP/IP, UDP, and advanced troubleshooting.
Expert-level tcpdump / Wireshark analysis skills — must be able to efficiently analyze complex SIP/SDP/RTP traces.
Hands-on experience with Spirent Landslide for SIP/RTP performance testing.
Strong experience with SIPp — creating custom scenarios, running high-scale load tests, and interpreting results.
Proficient in Python and Bash scripting for test automation, data parsing, and performance reporting.
Solid experience with SIP protocol in depth.

Strong Linux administration and performance tuning skills.

Recommended Experience
Free switch — configuration, performance tuning, and troubleshooting.
Kamailio (or OpenSIPS) — routing logic, performance optimization, and scaling.

Experience with high-availability SIP deployments in production environments.
Advanced scripting and automation (Python preferred).
Familiarity with media handling (RTP, RTCP, SRTP, codecs, transcoding).

Nice to have

Experience with other SIP platforms (Asterisk, etc.).
Knowledge of WebRTC, IMS, or 5G signaling.
Cloud-native experience (Kubernetes, Docker).
Background in database performance tuning (especially Postgre

SQL/MySQL in VoIP context).