Contact Person
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Dr.-Ing. Dragos Vingarzan
Senior Researcher 
Business Unit NGNI
Tel.: +49 30 3463-7385

Dragos Vingarzan is a senior researcher at the Business Unit NGNI (Next Generation Network Infrastructures).


Dragos Vingarzan graduated at the “Politehnica" University of Bucharest in February 2005 with a Diploma Thesis on the subject of service triggering in IMS, with a practical prototype implementation. During the 5-year study at the Faculty of Automatic Control and Computers he followed the Computer Engineering program on base software, compilers and computer networks.


Between 1999 and 2004, he gained valuable hands-on experience as a full-time employee at various national ISP and Telecom Operators. During this period he acted as software analyst/developer as well as project development leader in various projects for network monitoring, provisioning, management, billing and VoIP deployments.

During 2004 he worked on his Diploma Thesis at Fraunhofer FOKUS, which represented the first milestone of the Open IMS Playground.

Between 2005 and 2010 he was employed as a Scientific Researcher as the same institute, where he continued his work into the Open Source IMS Project, as well into feasibility and performance studies on NGN architectures.

Since 2010 he is acting as leader of the Reliable Network Infrastructure sub-group of NGNI, supervising the Open Evolved Packet Core (OpenEPC) project. His team of 15-20 researchers are concentrating on providing complete mobile network test-bed prototypes, with a special emphasis on flexible and cost-effective 2G, 3G, 4G and non-3GPP IP connectivity test-beds.

Currently he is working on his PhD study in the area of Open Source as an innovation bridge between the industry and the academia, with special interests in prototyping, open source in telecommunications, performance benchmarking and interoperability. He is an active member of various IMS and EPC working groups.

Related Links:

PhD Study

“Design and Implementation Aspects of Open Source NGN Test-bed Software Toolkits”

In the last decade, the Telecommunications world has taken a turn from the exclusive use of proprietary architectures, towards convergence with the Internet world concepts and technologies. The primary driver for this transformation is the highly innovative and cost-efficient nature of the Internet world with its openness, which has sparked dramatic changes not only to the communication domain itself, but also to the entire world, transforming our societies into connected ones. The Next Generation Networks (NGNs) aim to converge and bring together these technologies and the open innovation model, within the previously closed Telecommunications world, yet without compromising any of the traditional characteristics, like for example high reliability. Besides the technological convergence, the NGN effort also entails radical changes in the business models, as well as transforming the traditional Research and Development (R&D) models.

At the heart of the NGN architectures are the Core Network (CN) control models. These have transformed from closed systems towards open control platforms, where open innovation and competition will cater for best performance. Using Internet traditional protocols, yet specifically improved for higher performance demands, the NGN architectures are designed to provide the ultimate performance, reliability and predictability, as expected from the best network operators today. With flexibility and openness regarded as a primary drivers, service innovation and evolutions would be fast and efficient, providing the lean-factor to operators. Different domains like fixed, mobile or professional communications are all aiming for a common shared core architecture, with various access technologies and service platforms progressing along.

One of the most important catalysts of innovation in the Internet world is represented by the Open Source models, which empower large masses of innovators with the freedom to continuously drive its transformation. Such models have been regarded in the Telecom world first as efficiency increasing means, by replacing legacy non-essential proprietary systems with improved commoditized counterparts. Marking the beginning of the core architectures convergence were the Voice over IP (VoIP) concepts, which proved that similar telephony performance with much better flexibility can also be obtain with Internet world technologies.

The dissertation work starts from the experiences gathered through Open Source projects like the Fraunhofer FOKUS SIP Express Router (SER), which has quickly established itself as one of the best, most known and used signaling routing and processing platform for VoIP. On top of this success, a true NGN software toolkit is built, through the Open Source IMS Core project. The author has led the project and directly developed significant parts, such that today this is known and used as a world-wide reference for IP-Multimedia Subsystem (IMS)/NGN test-beds. Besides the implicit architectural validation and test-bed targets, such toolkits aim to provide solid R&D foundations not only for the industry but also for the academia, to educate and to build innovation bridges.

The primary scope of the dissertation will be to expose the main requirements, design decisions, implementation and exploitation steps which have been used in order to realize this prototype. A second step has already been started, as to better follow the NGN evolution from an IMS centric architecture towards a better generalized connectivity platform with the addition of Evolved Packet Core (EPC).

This provides the opportunity for an incremental step in refining the presented methods. Yet due to the sheer size of each of these projects, the focus will be kept here on the completed IMS toolkit, with the EPC one used mostly to prove that the described methodology, of using Open Source as innovation sparking catalyst in test-beds, is also sound and useful in a more generalized and systematized way.


Besides several industry projects on NGN research, Dragos is currently working on several academic research projects. If you are interested in participating or if you are an AV student looking for a nice project that will provide you with C/Java hands-on experience, the best NGN components insight as well as work experience into an internationally recognized Open Source project, while also gaining university credit for your work, do not hesitate to contact him directly. He is regularly guiding several students for AV projects as well as for Master Thesis.

The Open IMS Core is an implementation of IMS Call Session Control Functions (CSCFs) and a lightweight Home Subscriber Server (HSS), which together form the core elements of all IMS/NGN architectures as specified today within 3GPP, 3GPP2, ETSI TISPAN and the PacketCable initiative. The four components are all based upon Open Source software (e.g. the SIP Express Router (SER) or MySQL). For almost three years the Open IMS Core has formed the heart of the Open IMS Playground @ FOKUS.

SIPNuke is the flexible NGN load generator developed at the Fraunhofer FOKUS institute. Its key features are performance, flexibility and ease of use.

We, at FOKUS, have a very long R&D experience with SIP and IMS. And while we worked on this, we had a constant need for better tools: faster, easier to use, more flexible and easily extensible in the future.

Regardless of what you do with SIP or NGN, you always need a powerful, flexible, fast and easy to use test tool. SIPNuke was developed such that you could stop wasting time on testing your prototype/product/solution and keep concentrating on your core business.

The Open IMS Playground @ FOKUS is OPEN in a sense that it is in a constant process of evolving. It is open to new partners, new components, new technologies, as well as new concepts and paradigms. Then it is IMS (IP Multimedia Subsystem) centric. This means that it contains the latest IMS technology, conforms to the latest IMS specifications, and generally reflects the current state of the art in the field of IMS.

It is a PLAYGROUND. We see a Playground as a technology focused test environment, where we can “play" around with the latest technology. However, this is more than something to toy around with. It is a mature testbed, a test laboratory, where benchmarking, conformance tests and interoperability tests are carried out for our partners, and where components resulting from own development can be deployed and operated.

Driven by market needs and our partner's requirements, the Open IMS Playground has evolved to a known test laboratory which is used in many national and international projects from industry and academia.

OpenEPC is a prototype implementation of the 3GPP Evolved Packet Core (EPC). It enables academia and industry researchers and engineers around the world to obtain a practical look and feel of the capabilities of the Evolved Packet Core. OpenEPC Rel. 4, the current version available, includes all the components of the 3GPP architecture including the interfaces with various access technologies and service platforms. OpenEPC can be integrated with various access network technologies (including 2G/GPRS/EDGE, 3G/UMTS/HSPA, 4G/LTE, WiFi, etc) and different application domains and thus provides truly mobile broadband testbeds. In particular, the OpenEPC toolkit is designed to enable local and highly customized core network test-bed instantiations around the globe at the premises of various organizations.

The independent testbed for FUture SEamless COmmunication - FUSECO Playground

The progressing convergence of fixed and mobile networks, the seamless integration of multiple wireless access network technologies (WLAN, Femtocells, 2G/EDGE, 3G/HSPA, etc), the global introduction of 4G / Longterm Evolution (LTE) network technologies, as well as the fundamental changes in service delivery architectures based on emerging cloud technologies leads to new powerful communication control platforms, unifying the seamless, secure, Quality of Service based service provision across multiple access networks to different service control platforms.

Based on the experiences gained with the OpenIMS Playground and the Open SOA Telco Playground in establishing industry relevant testbeds for proof of concept implementations and interoperability testing of IP Multimedia Subsystem and Service Oriented Architecture based Service Delivery Platforms, the FOKUS FUSECO Playground has been launched in 2010 to practically understand the potentialities and limitations of the emerging 3GPP Evolved Packet Core (EPC) technology being introduced with LTE network role out for the seamless access to innovative applications, including human 2 human multimedia services, such as rich communications, emerging Machine 2 Machine services, as well as cloud based services. The FUSECO Playground offers an unique open infrastructure testbed to prototype and validate in an integrated multi-access network environment (DSL/WLAN/2G/3G/LTE/LTE-A) new concepts, components, protocols and helps to coin your vision of a Future Internet in areas like Smart Cities, Automotive, eHealth, eGovernment, Smart Metering and more.

The FUSECO Playground is an 3GPP Evolved Packet Core (EPC) centric, independent and open laboratory for mobile broadband communication research and development. It addresses large and small scale equipment vendors, network operators, application developers and research groups to testwise deploy and extend their components and applications before market introduction in order to manifest their advance in the international telecom market. In addition to the FOKUS OpenEPC toolkit, the FUSECO Playground also features the famous Open IMS Core and elevant enablers to gain experience with IMS-based Rich Communication Services (RCS) and Voice overLTE (VoLTE) services, as well as the OpenMTC toolkit, supporting an open range of machine 2 machine applications. In addition any internet or cloud-based service platform can be connected to this testbed in order to prototype new service concepts end 2 end across various network topologies.

Furthermore, the FUSECO Playground offers optional connections to the FOKUS Open SOA Telco Playground capabilities, in order to take advantage of newest service enablers and emerging Application Programming Interfaces (APIs) for rapid service creation and to benefit from emerging open innovation concepts adopted by next generation Service Delivery Platforms and Smart City service platforms.

Related Links:


D. Vingarzan, “A 3GPP IP Multimedia Session Handling implementation into SIP Express Router”, Diploma Thesis, “Politehnica” University of Bucharest, Faculty of Automatic Control and Computers, February 2005