Customer Support Quality Assurance

David C Vu

Address: Allen, Texas ***** Mobile: 469-***-****

Email: *******@*****.***

LinkedIn: For more feedback on my work performance, please refer to the recommendations section of my LinkedIn profile: www.linkedin.com/in/david-vu-7bbb005

PROFESSIONAL SUMMARY

Experienced 3G/4G Wireless Core Networks, VoIP, Mission Critical Push-to-Talk, IMS, and IP Networks System Integration, System Test/QA, Network Testing, and Customer Support Engineer with a proven track record in hardware and software integration, system testing, automation tool development, quality assurance, troubleshooting, and customer support. Demonstrates extensive expertise in wireless telecommunications and network technology, with a strong focus on software quality assurance and testing. Proficient in developing automation tools using Shell scripts, Python, Perl, and other programming languages for system KPI reporting and proactive monitoring. Authored comprehensive Methods of Procedure (MOPs) for system installation, deployment, and maintenance.

Skilled in creating test requirements, test plans, and test cases based on design solution documents and specifications. Proficient in setting up testbeds for system and network testing, including system sanity, regression, load/traffic, software integration, functional, end-to-end, and user acceptance testing. Demonstrated experience in automating system installations and deployments at customer sites. Strong expertise in Linux, automation, and script development, with extensive Tier 2/3 customer support experience, including troubleshooting and performing root cause analysis to ensure high product quality.

TECHNICAL SKILLS

3G/4G Wireless CALEA (Lawful Interception X1/X2/X3 & H1/H2/H3 interfaces): Testing/Troubleshooting & Protocol Analysis

Containerization: Kubernetes (K8s) and Docker Container.

Virtualization and Cloud Platforms: VMware and OpenStack

Scripting: Ansible, Linux Bash/Shell, Perl, Python, PowerShell, Terraform, VBA, TeraTerm, Windows DOS

Database: MySQL and PostgreSQL.

Applications: MS Word, Excel, PowerPoint, SharePoint

Networking and Tools: SFTP, DHCP, DNS, SNMP, TCP/IP IPv4/v6, iperf, tcpdump, netcat, Wireshark, and pcap analysis

Operating Systems: MS Windows, DOS, Unix, and Linux variants (RedHat, Rocky8, CentOS, Ubuntu)

Telecommunications: VoIP, MC-PTT, IMS, 3G, 4G LTE, 5G, SMS, MMS, RCS, SIP, DIAMETER, SS7

EXPERIENCE

Staff Engineer Samsung Electronics America Wireless Network Solutions

10/99 to 07/24 Plano, TX

Core Networks - VoIP/Mission Critical Push-to-Talk (MC-PTT - IMS based -5G) & IWF Projects 2017 - 2024

-Hardware and software integration and system testing of Samsung’s MCPTT IMS system & SS8’s Lawful Intercept system.

-Played a key role as the DevOps team lead, collaborating with the development team to successfully install, troubleshoot, test, and deploy the Lawful Intercept Kubernetes system. This system consists of a cluster of 21 VMs running on Linux Red Hat.

-Executed comprehensive software testing for VoIP, Push-To-Talk MCPTT IMS system and Lawful Intercept Linux based systems, including system interoperability, integration, security, feature testing, WebGUI testing, sanity, regression, acceptance, and load testing.

-Successfully conducted system installation using PowerShell, Ansible and Bash scripts, and performed test verification and validation for Rocky8 Linux-based MCPTT and IWF systems. Collaborated with clients to implement systems in a production environment and provided post-implementation support. Developed Methods of Procedure (MOPs), test plans, Test Objective Lists (TOLs), and test cases based on design solution documents and requirement specifications.

-Automation Team Lead. Designed and implemented automated proactive-monitoring tools and Golden Parameters checking tools for the system. Utilized Ansible, Perl, Python, and Linux shell/AWK scripts for system auto-provisioning, auto-configuration, and testing. Set up and operated Grafana and MySQL databases in the Linux VM for daily KPI monitoring tools.

-Collaborated with customers to troubleshoot and resolve network issues related to routers, switches, and firewall/ACL configurations and setups. Regularly utilized network sniffer tools for troubleshooting, such as tcpdump, netcat, netstat, and Wireshark, and demonstrated strong skills in analyzing pcap files for root cause analysis.

-Played a key role as DevOps/SRE (Site Reliability Engineering), engaged in the customer’s Agile/Scrum meetings, actively participating in the weekly reviews to track the progress and resolution of trouble tickets.

-Utilized the Nessus system for security scanning to identify vulnerabilities in the Linux VM and collaborated with the team to resolve them, taking into consideration the related Linux OS variant’s CVE database.

Utilized a combination of Windows servers and Oracle VM VirtualBox to create a variety of virtual machines with different operating systems, including MS Windows, RedHat, CentOS, Rocky8 Linux, Ubuntu, and others. This approach supported the needs of various applications, such as a Linux VM for sandbox testing, a Linux VM for Grafana KPI monitoring, a Windows VM for VPN access and tools, and a Linux Nagios VM for SNMP traps/alarms monitoring.

-Served as Subject Matter Expert (SME) for Lawful Intercept (CALEA) call processing and data features of Samsung’s MCPTT and SS8’s Xcipio Intercept system. Collaborated closely with customers to support Law Enforcement Agencies as required.

-Participated in a rotational schedule with team members to provide 24/7 on-call customer support.

Samsung Core Networks - VoIP, IMS 3G/4G LTE & Femto-Cell Projects 2006 - 2017

-Hardware and software integration and system testing of Samsung’s IMS 3G/4G LTE Wireless Core systems.

-Served as the Subject Matter Expert for the system’s CALEA, VoIP call processing and data features for the IMS, 3G & 4G Switches, SS8, and Verint Lawful Intercept systems. Collaborated closely with customers to support Law Enforcement Agencies during troubleshooting.

-Developed Methods of Procedure (MOPs), test plans, and Test Objective Lists (TOLs) with associated test cases. Executed system installation with Perl and Bash scripts, call processing testing, functional verification testing, and validation procedures for the 3G and 4G Linux-based core switch systems.

-Collaborated with customers to troubleshoot and resolve network issues related to network devices, such as routers, switches, and firewall/ACL configurations and setups. Regularly utilized network sniffer tools for troubleshooting, such as tcpdump, netcat, netstat, and Wireshark. Supported customers with post-system deployment and issues arising in both lab and production environments.

-Executed interoperability testing and evaluated call processing and supplementary services feature testing for Samsung SoftSwitch and Wireless Gateway products, in conjunction with other SoftSwitch vendors such as BroadSoft, Sylantro, MetaSwitch, and Sonus.

-Set up testbed, configured, and conducted testing for Network Management System (NMS) and Element Management System (EMS) servers running on Linux platforms. The test suite included Web GUI and Client/Server testing, manual and automated testing, security testing, integration testing, regression testing, performance testing, and logging/monitoring testing.

-Automation Team Lead. Designed and implemented automated proactive-monitoring tools and Golden Parameters checking tools for the system. Utilized Perl, TeraTerm, and Linux shell/AWK scripts for system auto-provisioning, auto-configuration, and testing. Developed Perl scripts, Visual Basic, and Excel tools with MySQL databases for the system’s daily KPI monitoring.

-Utilized Windows servers with Oracle VM VirtualBox to build various virtual machines with different operating systems, including MS Windows, Linux RedHat, CentOS, and Ubuntu, tailored for automation tools, script development sandboxes, and other diverse application purposes.

-Participated in a rotational schedule with team members to provide 24/7 on-call customer support.

Samsung Access Networks - L2/L3 Switches/IP Router, ATM/Frame Relay and xDSL Projects 1999 - 2006

-Hardware and software integration and system testing.

-Developed Methods of Procedure (MOPs), test plans, test cases, and automated test scripts based on system requirement specifications. Conducted system testing, end-to-end testing, and troubleshooting for various technologies, including VoIP (SIP-based), Ethernet Layer 2/3 switching, Routers, IP routing protocols (BGP, OSPF, RIP), ATM QoS (ATM Forum TM 4.0/4.1), IMA, Frame Relay, ADSL/ADSL2/ADSL2+, SHDSL, VDSL, and GR-303.

-Set up a data traffic testbed (ADSL, ATM, IP, and Fax) with VoIP bulk call traffic for long-duration performance testing. Performed voice and data combination capacity testing. Conducted data traffic QoS (Quality of Service) analysis and various traffic priority tests. Performed xDSL Forum’s inter-operability test plan (xDSL) for Samsung DSLAM products (based on TR-067/TR-069) at independent inter-operability test labs.

-Conducted system tests for Layer2 and Layer3 routers and IP routing protocols: MPLS, RIP, OSPF, and BGP.

-Provided Tier 2 and Tier 3 technical support. Traveled to customer sites to support lab trials and field trials.

Sr. SW Engineer Nortel Networks GSM Wireless Group

03/98 to 10/99 Richardson, TX

Member for the GSM Supplementary Services development team. Successfully completed multiple software design features and development cycles. Performed software enhancements and ported real-time software from the Central Processor Unit to the Peripheral Units to improve call processing speed.

Sr. SW Engineer Ericsson Inc. PCS 1900 Wireless Group

03/96 to 03/98 Richardson, TX

Led a software development team, overseeing team-based planning, software design, coding, unit testing, and system testing for new features and enhancements features for CMS88 Wireless Systems.

EDUCATION

Portsmouth University Bachelor Degree

Portsmouth, UK. B.Eng. (Honors) Degree in Engineering

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