Publications

Accepted papers

Athanasios Christakidis, Jens Fiedler, Nikolaos Efthymiopoulos, Konstantinos Koutsopoulos, Evangelos Markakis, Stephen Garvey, Spyros Denazis, Spyridwn Tombros, Shane Dempsey, Evangelos Pallis, Odysseas Koufopavlou: "Integrating P2P with Next Generation Networks"

This chapter describes the major components and their interactions of a novel architecture called VITAL++ that combines the best features of the two seemingly disparate worlds, Peer-to-Peer (P2P) and NGN in particular IMS, which are then used to support multimedia applications and content distribution services. To this end, P2P is enhanced with advanced authentication, DRM mechanisms while NGN benefits from the enhanced scalability, reliability and efficient distribution of service and content by exploiting P2P self - organization properties. We describe novel P2P algorithms for optimizing network resources in order to efficiently distribute content among various users without resorting to laborious management operations required in NGN.

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Nikolaos Efthymiopoulos, Spyridon L. Tompros, Athanasios  Christakidis, Konstantinos Koutsopoulos, Spyros Denazis: "Enabling live video streaming services realization in telecommunication networks using P2P technology", Wiley International Journal of Communication Systems, March 2011

Peer-to-peer (P2P) systems enjoy wide adoption from internet users. Success of P2P architecture is due to its ability to scale and to organize dynamically the traffic according to the user resources and requests. On the contrary, P2P adoption is constrained in non-real time applications, like content distribution and file sharing. The major reason behind this fact is the inability of P2P to deliver content within user-desired bit rates by making optimize use of network resources. In this paper we focus on the solution and the implementation of technical problems towards a complete system implementation that delivers live multimedia streaming through P2P architecture by the use of IMS. The content indexing and discovery, the scalable management and the distributed optimization of the graph that connects participating peers, the distributed scheduling mechanisms for data exchange, a scalable monitoring architecture and a bandwidth control mechanism constitute the major components towards a complete scalable multimedia streaming system offering streaming stability and high performance.

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Christakidis A, Efthymiopoulos N, Fiedler J, Dempsey S, Koutsopoulos K, Denazis S, Tombros S, Garvey S,Koufopavlou O: "VITAL++ a new communication paradigm: embedding P2P technology in next generation networks", IEEE Communications Magazine, January 2011, Vol. 49, No 1, pp. 84-91

This paper describes the major components and their interactions of a novel architecture called VITAL++ that combines the best features of the two seemingly disparate worlds, Peer-to-Peer (P2P) and NGN in particular IMS, which is then used to support multimedia applications and content distribution services. To this end, P2P is enhanced with advanced authentication and DRM mechanisms while NGN have become more scalable, reliable and less centralized by exploiting P2P self-organization properties. We describe novel P2P algorithms for optimizing network resources in order to efficiently distribute content among various users without resorting to laborious management operations required in NGN.

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Efthymiopoulos N. Deploying and Experimenting with new control architectures: "The VITAL++ case." 3rd EU-Japan Symposium on Future Internet and New Generation Networks, 20-22 October 2010 Tampere, Finland.

TEMU 2010 - Workshop: Identifying Enabling Technologies for Future Internet Experimentation.

Nico De Abreu Pereira, Rundfunk Berlin-Brandenburg, "Making Use of VITAL++ - Use Case Scenarios for IMS-based Peer-to-Peer Services"

Nikolaos Efthymiopoulos, University of Patras, "VITAL++ Peer-to-Peer Content Distribution - Architecture and Technical Solutions"

Jens Fiedler, Fraunhofer FOKUS, "Peer-to-Peer Security and Authentication"

Shane Dempsey, TSSG/WIT, "VITAL++ Reference Services Adaptation"

J. Mueller, T. Magedanz, J. Fiedler: "Peer Assist Live Streaming Overlay for Next-Generation-Networks", International Journal of Handheld Computing Research, Vol. 1, No. 4, pages 25-40, October-December, 2010.

 

J. Fiedler, T. Magedanz, J. Mueller: "Extending an IMS Client with Peer-to-peer Content Delivery", pp. 197-207, Second ICST International Conference on MOBILe Wireless MiddleWARE, Operating Systems, and  Applications - MOBILWARE 2009, Berlin, Germany, April 29, 2009, www.mobilware.org

http://www.mobilware.org

The increasing demand for mobile applications implies an increase in service availability and content delivery capacities across the networks. Peer-to-peer technologies have proven to be able to deliver media in an effective way to the end user. In this paper, we analyze and describe the necessary extensions and functionalities, which are needed to enable Peer-to-peer content delivery in an IMS client, namely the MONSTER framework. A special focus is directed to the interoperation between existing functional elements and newly developed peer-to-peer components.

J. Mueller, T. Magedanz, J. Fiedler: "NNodeTree: A Scalable Peer-to-Peer Live Streaming Overlay Architecture for Next-Generation-Networks" in the Volume 1, Issue 2 of the International Journal of Network Protocols and Algorithms (ISSN: 1943-3581)

The rapid evolution of the telecommunication domain increases the performance of different access networks continuously. New services, especially in the domain multimedia content distribution, require higher and higher bandwidth at the user’s and service provider’s side. Multimedia services like Video on Demand, IPTV and live streaming were introduced in the past and are still improved in quality and quantity. Multimedia streams and Peer to Peer (P2P) file sharing dominates the worldwide Internet traffic nowadays and will continue further.

The user acceptance of enjoying multimedia content over the Internet will grow steadily together with the increasing quality of the available multimedia content. Network operators and service providers have to face the growths, by either increasing their service platform with higher performance and bandwidth or introducing a scalable solution.

We present the design and implementation of a scalable Peer-to-Peer live streaming overlay architecture for Next-Generation-Networks (NGN) in this paper that addresses this challenge.

http://www.macrothink.org/journal/index.php/npa/issue/view/32/showToc

Christakidis Athanasios, Efthymiopoulos Nikolaos, Denazis Spyros, Koufopavlou Odysseas: "On the architecture and the design of P2P live streaming system schedulers", ICUMT, International Conference on Ultra Modern Telecommunications 12-14 October 2009, St. Petersburg, Russia

In this paper we analyze the technical objectives that p2p block schedulers have to meet in order to deliver live streaming with p2p architecture. We present an initial attempt towards the development of a p2p live streaming scheduler. We also compare our scheduling approach with other schedulers in the same conditions in order to have a fair and useful comparison.

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Efthymiopoulos Nikolaos, Christakidis Athanasios, Denazis Spyros, Koufopavlou Odysseas : "L-CAN Locality aware structured overlay for P2P live streaming", 11th IFIP/IEEE International Conference on Management of Multimedia and Mobile Networks and Services (MMNS) 22-26 September 2008, Samos, Greece

In this work we propose the exploitation of network locality in order to have a DHT that reflects the underlying network conditions and topology. The DHT that we use is a symmetric graph and so it is suitable for applications that have such a requirement. We also evaluate the performance of it through our simulations.

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Pending papers

Efthymiopoulos N, Christakidis A, Giacomin P, Denazis S, Koufopavlou O. : "QoS - LiquidStream: Scalable monitoring and bandwidth control in P2P live streaming", submitted at Elsevier Communication Networks

There is a lot of research work that has recently focused on P2P live streaming. As a result a lot of algorithms and system architectures have been proposed that achieve high upload bandwidth utilization of the participating peers, low delays during stream diffusion while systems are stable under dynamic network conditions and peer behavior. However, these systems make the assumption that the average upload bandwidth capability of the participating peers is stable and greater than the bandwidth the system requires for the successful delivery of the video stream, an assumption that makes these system impractical. This paper relaxes this assumption by proposing a monitoring mechanism for the total upload bandwidth capabilities of the participating peers, which is scalable, accurate, dynamic and with low overhead. Exploiting this monitoring mechanism, we also present and evaluate a method that allows the accurate and timely estimation of the required (minimal) amount of bandwidth that an external set of resources has to contribute in order to maintain uninterrupted stream delivery at the specified quality, thus making P2P systems practical for use.

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Efthymiopoulos N, Christakidis A, Denazis S, Koufopavlou O. Liquidstream – network dependent dynamic P2P live streaming, Springer Peer-to-Peer Networking and Applications, March 2011, Vol. 4, No 1, pp. 50-62

A successful P2P live streaming system must achieve high uploading bandwidth utilization, fast stream distribution, uniform bandwidth distribution among participating peers, flexibility and adaptation to the underlying network conditions and peer behavior. This paper proposes a novel architecture that meets these requirements. By the use of distributed optimization algorithms we propose a dynamically reconfigurable overlay architecture that organizes its peers according to network locality information and heterogeneous uploading capabilities of them. The benefits of our optimized overlay are fully exploited by our proposed scheduler, which guarantees the complete and fast distribution of the stream. The evaluation of our system under a series of scenarios that take into account the all requirements above reveals the advantages of our proposed system.

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