PROJECTS AND PROFESSIONAL EXPERIENCE:

Confidential, Philadelphia, PA

Responsibilities:

• Hands - on project of emulation and back-to-back testing VoIP calls between set-top boxes and backend server infrastructure to serve over 10 million subscribers.
• Project tasks included daily cross-team collaboration (WebRTC, DevOPs, NETOP, AntiAbuse), Scrum meetings, issue resolution calls.
• Implemented software with third-party tool integration for modeling production scenarios with audio/video streaming and simulating user devices behind NAT to establish Voice over IP and other real-time media capabilities (audio and video RTP payloads and different codecs).
• Developed proof of concept including FreeSWITCH and SIPp for performance/load testing user scenarios in production VOIP networking infrastructure based on OpenStack cloud virtual machines.
• Designed call flow and state transition diagrams, analyzed packets in Wireshark and tcpdump .

Confidential, Parsippany, NJ

Project leader

Responsibilities:

• Performed daily sustaining engineering tasks solving customer’s issues with VoIP, including: initial triage, reproduction customer cases with software/hardware, implementation fixes, unit and regression testing.
• Supported Unified Communications (UC) solutions based on Confidential (SIP, PSTN integration) .
• Successfully resolved numerous escalations and Top-10 issues with required daily status update.
• Debugged Interop issues with VoIP equipment from many manufactures (Cisco, Avaya, Hitachi, Asterisk, Convergys, Unisys, Genesys, other softswitches).
• Analyzed logs from the field using Wireshark, debugged software state machines, analyzed crash dumps, opened tickets and submitted to developers, use case troubleshooting, traced resource leaks, stuck channels and state machine deadlocks.
• Developed new functionality and fixed software issues with IP and ISDN call control (4ESS, 5ESS, QSIG, T1/E1, other ISDN) and media processing (SIP, H.323, RTP with different payload types).
• Integration and regression testing with SIP phones, analog phones, protocol emulators, proprietary automated scripting tools.
• Resolved issues with different telecom protocols and signaling (SIP, H.323, RTP, CAS, SS7, TDM, voice and fax over IP, PSTN, Radvision SIP/H.323 stack).
• Debugged messaging and latency errors with hardware and software on Windows and Linux, provided overlays for the customers, version control and configuration management, performed peer reviews.
• Supported company’s application engineers, resolved Escalated Service Requests from users remotely and on the field.
• Developed user documentation including call flow and state transition diagrams.

Consultant

Confidential

Responsibilities:

• Project to upgrade Department Computer Telephony distributed phone system with call control and voice recording (IVR), including migration to Windows servers, implementation of software and hardware from several vendors, database connectivity with Oracle Rdb backend.
• New development and hands on integration with existing modules including finance subsystems based on HP OpenVMS.
• Successfully implemented applications with over 100 simultaneous calls handlers per server, menu structures, external resource lookup, visual control interface.
• Organized phone conferences with equipment vendors (Intel, HP), debugged issues with Teltronics(Harris) 20/20 legacy PBX, set up and configured networking equipment, implemented vendor’s recommendations.
• Prepared user documentation (manuals, diagrams, instructions, troubleshooting charts) for department personnel.
• Took part in several emergency operations, weekend and after hours remote support of 24/7 system.

Contractor

Confidential, New York, NY

Responsibilities:

• Project to develop and implement algorithms of Least Cost Routing calculation for wholesale VoIP traffic with programming/scripting, database, and web interface (LAMP).
• This solution had immediate monetary effect and substantially increased the company’s revenue.
• Developed several scripting solutions for VoIP Call Detail Record analysis (SIP and H.323 CDRs), automated data collection, and route quality parameter processing based on Asterisk and Mera softswitches.

Confidential, Brooklyn, NY

Project leader

Responsibilities:

• Assigned tasks, managed testing and developed software for e-commerce Web-frontend project using PHP and MySQL on FreeBSD.
• Designed unique applications for big data presentations to backend operators and administrators using database concepts and complex logic: grouping to sub-systems, indexing, identification, linking with images and external documents.
• Design algorithms for product search which pulls data using SQL, stores data structures in memory, sorting and data filtering, displays results in html with product groups cross-linking.
• Installed and configured equipment in data centers, remote monitoring, load and performance analysis, managed access policy and VPN.
• Analyzed and changed FreeBSD and Linux internals, developed scripts to control system health and performance, performed debugging based on information in system logs, modified kernel parameters, compiled and installed applications from port sources.
• Daily communication with developers and data entry personnel, prepared diagrams and schemas for operations, instructions, use case manuals.
• Developed visual forms and batch programs on Visual FoxPro for billing and call statistics automated processing of CDRs from national branch exchange serving over 5 million people.
• Developed drivers for T1/E1 card running RTEMS based on embedded real time system for SDH multiplexer (C, gnu cross-compiler and binary tools).
• Designed embedded tasks for STM-1 equipment control using Motorola MC68EN302 communication processor.
• Implemented X.25 to IP gateway solution: multithreading, proprietary library integration, connection to networking devices, debugging and operations.
• Installed Cisco equipment on client sites including wireless access points, dial-up, consoles, routers and switches.
• Debugged wiring issues, installed modules and cards, performed firmware upgrades, configured multi-protocol gateways.