Igor Delac, VoIP Developer in Split, Croatia
Igor Delac

VoIP Developer in Split, Croatia

Member since April 9, 2014
Igor is a highly skilled technology enthusiast with over 13 years of experience in Java development, system administration, and more. He loves to experiment and work with new technologies. Igor is very proud of his ability to learn whatever is necessary to solve a problem at hand.
Igor is now available for hire

Portfolio

Experience

  • Linux 10 years
  • VoIP 9 years
  • Java 7 years
  • Spring LDAP 4 years
  • SQL 4 years
  • Vaadin 3 years
  • LDAP 3 years
  • Spring 5 2 years

Location

Split, Croatia

Availability

Part-time

Preferred Environment

Eclipse, NetBeans

The most amazing...

...built a VoIP recording system for Cisco CallManager via test-driven development.

Employment

  • Java Developer

    2017 - PRESENT
    SedamIT d.o.o.
    • Developed a lawful interception system for monitoring telecom network traffic.
    • Created an RMS system for active VoIP call recording.
    Technologies: Maven, Eclipse, Event-driven Programming, Spring, Git, PostgreSQL
  • Java Developer

    2013 - 2015
    Ericsson Nikola Tesla
    • Tested and coded a provisional gateway for HLR.
    • Created support for LDAP by implementing openLDAP and custom Java LDAP servers.
    • Built a high-performance LDAP server.
    • Developed support for Linux tools.
    • Optimized the TCP stack on Linux 2.6 and 3.0 kernel series.
    Technologies: Eclipse, UnboundID, Event-driven Programming, LDAP, Git, Java, Linux
  • Software Tester

    2011 - 2012
    Ericsson San Jose
    • Installed the Entrisphere/Ericsson BLM1500 multiplexer.
    • Tested BLM1500 data, video, and voice services for the Spirent Test Center.
    • Installed and supported Asterisk PBX for testing VoIP.
    • Configured extreme L3 Switches.
    • Troubleshot networks.
    • Tested GPON access to the network with ONT terminal provisioning.
    Technologies: GPON, UnboundID, Event-driven Programming, Git, SQL
  • Integration and Verification Engineer

    2008 - 2011
    Ericsson Nikola Tesla
    • Conducted support for test tools.
    • Tested Linux-based elements of Telephony Softswitch Solution 4.0.
    • Troubleshot and diagnosed network problems.
    • Conducted SIP protocol analysis.
    • Integrated site system testing via installation and configuration of TGC/MGW elements.
    Technologies: GPON, UnboundID, Git, Telephony
  • Network Administrator

    2007 - 2007
    Siemens PSE
    • Supported the introduction of multicast in the company network.
    • Created documentation for the network.
    • Diagrammed network connections.
    • Tested multicast on Cisco switches.
    • Tested multicast across routers.
    • Created final documentation and reported on test results.
    Technologies: Multicast, Cisco

Experience

  • SIP Load Balancer
    https://code.google.com/p/lb-sip/

    A simple Java application which will do load balancing across several SIP servers, based on list, or periodic reports from SIP servers.

  • VoIP Call Recording System
    http://scoreunit.com/voiprecorder.html

    A Java-based back-end system for VoIP call recording that used Spring for the back end and Vaadin for the UI.

    It included:
    • SIP, RTP protocols, compression using G.729 standard.
    • OPUS encoder and decoder with OGG file container.

    Designed an alarm subsystem and the web UI.

  • Blagajna
    https://code.google.com/p/blagajna1/

    A simple Java GUI application for issuing printed receipts on cashier systems, completed according to Croatian legislative requirements.

  • Simple Management System
    http://git.toptal.com/Igor-Delac/igor-delac-2nd-attempt/wikis/home

    A simple management front-end application coded in Java FX, to demonstrate REST approach and FX user interfaces. Back-end PHP and SQL scripts are also provided for integration into Apache web servers with a PHP module and MySQL database.

  • VNC Server Library for Java
    https://github.com/idelac3/RFBService

    A VNC allows remote connection and control of the host system, and it is used as an alternative to Microsoft RDP and TeamViewer.

    This project shows how to implement the server-side protocol in pure Java. The official name of the protocol is "Remote Frame Buffer," or RFB for short.

    This project compiles into a Java library as a JAR file, and it is also available as a Maven artifact.

  • Launching a Spring Boot Application Programmatically (Publication)
    Starting a Spring Boot application in the command line is as simple as it gets. But what if we want to run our application from another Java program? In this article, Toptal Java Developer Igor Delac demonstrates how you can start a Spring Boot app programmatically using just a few lines of code.
  • Implementing a Remote Framebuffer Server in Java (Publication)
    Connecting to remote computers and working on them through terminals over a network is something we often take for granted. Technologies that enable us to do this have changed the way we work and have opened doors to amazing possibilities. Although the inner workings of these technologies may seem like obscure knowledge, implementations of many of these technologies are surprisingly straightforward. In this article, Toptal engineer Igor Delac gives us a step-by-step tutorial on how to implement the Remote Framebuffer server-side protocol in Java, allowing Swing-based applications to run and be interacted with remotely using standard VNC clients.

Skills

  • Languages

    Java, Bash, Assembler, SQL
  • Frameworks

    Spring, Spring 5, Vaadin, Apache CXF, Thymeleaf
  • Libraries/APIs

    Spring LDAP, libvirt
  • Tools

    Maven, Asterisk, Remote Framebuffer Protocol (RFB), Eclipse IDE, OpenVPN, KVM/Qemu, Git
  • Paradigms

    Procedural Programming, Event-driven Programming, ASN.1
  • Platforms

    Linux, JavaFX, UnboundID, Eclipse, NetBeans, Apache Kafka
  • Other

    Cisco, Telephony, LDAP, VoIP, Session Initiation Protocol (SIP), RTP, Multicast, GPON, FreeSWITCH PBX, CallManager, PKI
  • Storage

    PostgreSQL

Education

  • Master's Degree in Electrical and Software Engineering
    2002 - 2008
    J. J. Strossmayer University - Osijek

Certifications

  • CCNA
    APRIL 2012 - PRESENT
    Cisco

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