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.

• Freeswitch — 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 PostgreSQL/MySQL in VoIP context).