Network QA

This is a 6 month contract and involves close collaboration with multiple technical teams and business stakeholders to oversee end-to-end (E2E) migration programs. The successful candidate will be responsible for end-to-end network testing of a new mobile core, devices, and services across lab, pre-production, and production environments, with a focus on the physical network lab located in Dublin.

Specific Duties & Tasks: (On Lab, Pre-Production & Production Environments)

Telecom Network Testing (2G, 3G, 4G):

• Conduct comprehensive testing of voice, data, and SMS services across 2G, 3G, 4G networks, ensuring high-quality network performance.
• Ensure network quality by testing and analyzing call flows, registration flows, data flows, and SMS flows across all mobile technologies.
• Test the performance and reliability of network protocols, including GSM, UMTS, and LTE, in real-world scenarios.
• Collaborate with relevant teams to test Mobile Virtual Network Operator (MVNO) infrastructure, ensuring smooth operation and customer satisfaction.

SBC, STP, and Network Element Tracing:

• Perform tracing and analysis of Session Border Controllers (SBC) for monitoring and troubleshooting signaling and media flows related to voice, SMS, and data services.
• Conduct tracing and troubleshooting on Signal Transfer Points (STP) to monitor SS7 signaling and ensure proper call setup, registration, and routing.
• Work with other critical network components specific to MVNOs, including HSS (Home Subscriber Server), GGSN/PGW (Gateway GPRS Support Node/Packet Gateway), HLR (Home Location Register), VLR (Visitor Location Register), and MSC (Mobile Switching Center) to ensure seamless network performance.
• Evaluate network performance across MVNO architecture, identifying issues in signaling, call drops, or data service anomalies, and working towards efficient resolution.

Voice, SMS, and Data Services Testing:

• Perform in-depth testing of voice services, including call quality, call setup, and handover across different network bands.
• Validate the performance and delivery of SMS services, ensuring proper message routing, delivery success, and interoperability across multiple networks.
• Conduct thorough testing of data services to ensure optimal throughput, latency, jitter, and overall performance metrics for data traffic across different network technologies.

Wireshark and Network Analysis Tools:

• Use Wireshark and similar network analysis tools to capture and analyze traffic across various telecom protocols, identifying issues related to packet loss, latency, and throughput.
• Decode, analyze, and troubleshoot protocols like SS7, SIP, Diameter, S1AP, GTP, and RTP to resolve issues with voice, SMS, and data flows.
• Effectively utilize Wireshark to pinpoint and resolve anomalies in network performance, ensuring optimal network operations.

STE3000 Series and Protocol Testing:

• Leverage STE3000 series testing tools to conduct in-depth network quality assessments. (Understanding of STE3000 series is considered a plus but not mandatory).
• Ensure compliance with telecom protocols by analyzing protocol traces and ensuring proper handling of network traffic, session establishment, and call termination across multiple network layers.

SBC, STP, and Network Component Monitoring:

• Actively monitor SBC and STP operations to ensure proper handling of signaling messages and media sessions.
• Troubleshoot network issues related to these elements by analyzing signaling traces and performing root cause analysis.

Quality Assurance and Defect Tracking:

• Manage and track defects using Jira or Bugzilla to ensure quick identification, reporting, and resolution of network issues.
• Participate in cross-functional teams to diagnose and resolve MVNO-related network problems and ensure seamless user experience.

MVNO Integration Testing & Collaboration and Stakeholder Management:

• Conduct integration testing for MVNO services, ensuring that third-party systems, including subscriber management, billing, and roaming, are fully compatible with the existing network infrastructure.
• Collaborate with MNO (Mobile Network Operator) partners to test roaming agreements, interoperability, and ensure a smooth user experience for MVNO subscribers.
• Work closely with technical teams, including network engineering, devops, and core network teams, to ensure seamless communication and collaboration across the testing lifecycle.
• Collaborate with business stakeholders to understand and meet technical and operational requirements for network services and migration projects.
• Serve as the point of contact for all Network QA-related matters, providing updates on testing progress, challenges, and outcomes to senior management.

Mobile Core and Device Testing:

• Lead the QA efforts for the new mobile core infrastructure and its integration with the existing network.
• Test and validate mobile devices within the network lab, ensuring compliance with network standards and performance benchmarks.
• Ensure testing covers both legacy systems and new network services, confirming that all services are delivered without disruption during the migration process.

Performance Monitoring and Testing Automation (optional but Is a plus):

• Employ performance monitoring tools such as Nagios, Zabbix, and Cacti to track key performance indicators (KPIs) like call drop rate, data throughput, and network latency.
• Develop and implement automated test cases using automation frameworks such as Selenium, Robot Framework, and Cucumber to streamline quality assurance processes.
• Use scripting languages such as Python and Perl to automate repetitive testing tasks and gather in-depth insights into network behaviour.

Skills & Expertise:

Telecom Network Expertise (2G, 3G, 4G):

• Strong knowledge of 2G, 3G, and 4G, including their network architectures, protocols (GSM, UMTS, LTE), and testing methodologies.
• Deep understanding of call flows, registration flows, data flows, and SMS flows across all telecom networks and their application in MVNO environments.

SBC, STP, and Network Element Expertise:

• Proficiency in tracing and troubleshooting SBC and STP for signaling issues related to voice, data, and SMS services.
• Knowledge of additional network elements like HSS, GGSN/PGW, HLR/VLR, MSC, and DNS specific to MVNO architecture.

Wireshark and Network Analysis Tools:

• Expertise in using Wireshark and other network analysis tools to capture, analyze, and troubleshoot network traffic across multiple protocols (SS7, SIP, Diameter, GTP).
• Strong protocol analysis skills for decoding SS7, SIP, S1AP, RTP, and GTP messages to ensure network reliability.

STE3000 Series Knowledge:

• Familiarity with STE3000 Series testing tools for network quality assessments is considered a plus.

Defect Tracking and Performance Monitoring:

• Proficiency in using defect tracking tools like Jira and performance monitoring tools like Nagios, Zabbix, or Cacti for tracking network performance and identifying areas for improvement.

MVNO Integration and Testing:

• Understanding of MVNO architecture and experience testing MVNO-specific services, ensuring interoperability and seamless integration with host MNO networks.

The Person:

• The ability to communicate effectively and efficiently with the business while ascertaining the key impact/detail behind the issue/request
• Excellent stakeholder management skills to manage both internal, central and third-party relationships
• Strives to be the best in everything they do, challenges ideas and constantly innovates
• Ability to work in a fast-paced environment, be flexible and embrace change
• Extremely organised and a methodical approach to both daily tasks and project work
• Excellent management skills; highly self-motivated and constantly inspiring others
• Willingness to handle testing during potential night shifts and extra hours if required, ensuring continuity of network testing during critical project phases