Change search
Refine search result
1 - 14 of 14
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Live Streaming Performance of Peer-to-Peer Systems2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In peer-to-peer (P2P) live streaming systems peers organize themselves in an overlay and contributewith their resources to help diffuse live content to all peers in a timely manner. The performanceof such systems is usually characterized by the delay-loss curve, which quantifies theplayback delay required for achieving a certain streaming quality, expressed as the chunk missingratio at the peers. The streaming quality is determined by the overlay construction algorithm, theforwarding algorithm, the loss process in the underlying network, the number of peers in the overlayand their bandwidth distribution, the willingness of the peers to contribute with their resourcesand the viewing behavior of the peers (churn). The overlay construction and forwarding algorithmsare inherent characteristics of a P2P protocol, while the remaining factors are artifacts of thedeployment of the P2P system over a best-effort network such as the Internet, as well as the factthat peers act as independent agents. The current thesis addresses the problem of evaluating andimproving the performance of P2P streaming protocols based on models of the network and of thepeers' behavior. The first part of the thesis is devoted to the performance evaluation of P2P overlay constructionand forwarding algorithms and offers three contributions. First, we study the efficiency of datadistribution in multiple tree-based overlays employing forward error correction. We deriveanalytical expressions for the average packet possession probability as well as its asymptoticbounds and verify our results through simulations. Second, we evaluate the performance of astreaming system in the presence of free-riders. We define two admission control policies and studythe streaming feasibility using an analytical model and via simulations. Third, we present ananalytic framework for the evaluation of forwarding algorithms in mesh-based systems. We validate itvia simulations and use it to evaluate and to compare four push-based forwarding algorithms in termsof their delay-loss curves. The second part of the thesis investigates potential improvements to the operation of P2P streamingsystems and offers three contributions in that area. First, we study the impact of selfish peerbehavior on streaming quality in overlays where a fraction of peers has limited contribution due tophysical constraints. We show that selfish peer behavior results in suboptimal streaming quality andwe propose an incentive mechanism that increases the streaming quality by using the server uploadcapacity to reward high contributing peers. Second, we study the problem of building network aware P2P streaming overlays, taking into accountrecent measurement results that indicate that the AS-level topology of the Internet is flattening.Through extensive simulations on regular and measured topologies we show that it is possible tocreate better than random overlays relying on information about the underlying topology. Finally, westudy the problem of playout adaptation in P2P streaming systems under churn. We propose andevaluate two algorithms that tune the playback delay of the peers in such a way that the streamingquality of the peers is maintained within predetermined limits. We use simulations to show thecorrectness of the proposed algorithms and the benefits from their use.

  • 2.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Maximizing streaming quality in heterogeneous overlays through incentives2009In: Proceedings of the 2009 ACM Conference on Emerging Networking Experiments and Technologies, CoNEXT'09 - Co-located Student Workshop, CoNext Student Workshop '09, 2009, p. 35-36Conference paper (Refereed)
    Abstract [en]

    The upload contribution of peers in a peer-to-peer streaming system depends on their willingness to contribute as well as their physical limitation. Several incentive schemes have been proposed to enforce non-willing peers to cooperate. But we find it of great interest to see how physically constrained, with respect to resources, peers can be supported by a streaming application. In this paper we investigate how free-riders, namely non-contributing peers, can be served in a peer-to-peer streaming system. We examine different prioritization schemes that are used by high contributing peers to prioritize other contributing peers over free-riders and show that as the level of prioritization increases, contributing peers receive higher quality but the average quality drops. To avoid this, we propose an incentive mechanism that encourages contributing peers to upload to free-riders so that the average quality experienced by the peers in the overlay is maximized.

  • 3.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    P2P Live Video Streaming2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The ever increasing demand for video content directed the focus of researchfrom traditional server-based schemes to peer-to-peer systems for videodelivery. In such systems, video data is delivered to the users by utilizing theresources of the users themselves, leading to a potentially scalable solution.Users connect to each other, forming a p2p overlay network on top of theInternet and exchange the video segments among themselves. The performanceof a p2p system is characterized by its capability to deliver the videocontent to all peers without errors and with the smallest possible delay. Thisconstitutes a challenge since peers dynamically join and leave the overlay andalso contribute different amounts of resources to the system.The contribution of this thesis lies in two areas. The first area is theperformance evaluation of the most prominent p2p streaming architectures.We study the streaming quality in multiple-tree-based systems. We derivemodels to evaluate the stability of a multiple tree overlay in dynamic scenariosand the efficiency of the data distribution over the multiple trees. Then, westudy the data propagation in mesh-based overlays. We develop a generalframework for the evaluation of forwarding algorithms in such overlays anduse this framework to evaluate the performance of four different algorithms.The second area of the thesis is a study of streaming in heterogeneous p2poverlays. The streaming quality depends on the aggregate resources that peerscontribute to the system: low average contribution leads to low streamingquality. Therefore, maintaining high streaming quality requires mechanismsthat either prohibit non-contributing peers or encourage contribution. In thisthesis we investigate both approaches. For the former, we derive a model tocapture the evolution of available capacity in an overlay and propose simpleadmission control mechanisms to avoid capacity drainage. For the latter, inour last work, we propose a novel incentive mechanism that maximizes thestreaming quality in an overlay by encouraging highly contributing peers tooffer more of their resources.

  • 4.
    Chatzidrossos, Ilias
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dán, György
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Playout Adaptation in Peer-to-Peer Systems Under Churn2012In: 2012 19th International Packet Video Workshop, PV 2012, IEEE , 2012, p. 119-124Conference paper (Refereed)
    Abstract [en]

    We address the problem of playout adaptation in peer-to-peer streaming systems. We propose two algorithms for playout adaptation: one coordinated and one distributed. The algorithms dynamically adapt the playback delay of the peers so that the playout miss ratio is maintained within a predefined interval. We validate the algorithms and evaluate their performance through simulations under various churn models. We show that playout adaptation is essential in peer-to-peer systems when the system size changes. At the same time, our results show that distributed adaptation performs well only if the peers in the overlay have similar playback delays. Thus, some form of coordination among the peers is necessary for distributed playout adaptation in peer-to-peer streaming systems.

  • 5.
    Chatzidrossos, Ilias
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dán, György
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktória
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Delay and playout probability trade-off in mesh-based peer-to-peer streaming with delayed buffer map updates2009In: Peer-to-Peer Networking and Applications, ISSN 1936-6442, E-ISSN 1936-6450, Vol. 3, no 3, p. 208-221Article in journal (Refereed)
    Abstract [en]

    In mesh-based peer-to-peer streaming systemsdata is distributed among the peers according tolocal scheduling decisions. The local decisions affecthow packets get distributed in the mesh, the probabilityof duplicates and consequently, the probabilityof timely data delivery. In this paper we proposean analytic framework that allows the evaluation ofscheduling algorithms. We consider four solutions inwhich scheduling is performed at the forwarding peer,based on the knowledge of the playout buffer contentat the neighbors. We evaluate the effectiveness of thesolutions in terms of the probability that a peer can playout a packet versus the playback delay, the sensitivityof the solutions to the accuracy of the knowledge of theneighbors’ playout buffer contents, and the scalabilityof the solutions with respect to the size of the overlay.We also show how the model can be used to evaluatethe effects of node arrivals and departures on the overlay’sperformance.

  • 6.
    Chatzidrossos, Ilias
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dán, György
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktória
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Server Guaranteed Cap: an incentive mechanism for maximizing streaming quality in heterogeneous overlays2010In: NETWORKING 2010, PROCEEDINGS / [ed] Crovella M; Feeney LM; Rubenstein D; Raghavan SV, 2010, p. 315-326Conference paper (Refereed)
    Abstract [en]

    We address the problem of maximizing the social welfare in a peer-to-peel streaming overlay given a fixed amount of server upload capacity. We show that peers' selfish behavior leads to an equilibrium that is suboptimal in terms of social welfare, because selfish peers are interested in forming clusters and exchanging data among themselves In order to increase the social welfare we propose a novel incentive mechanism: Server Guaranteed Cap (SGC), that uses the server capacity as an incentive for high contributing peers to upload to low contributing ones We prove that SGC is individually rational anti incentive compatible We also show that under very general conditions, there exists exactly one server capacity allocation that maximizes the social welfare under SGC, hence simple gradient based method can be used to find the optimal allocation

  • 7.
    Chatzidrossos, Ilias
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dán, György
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Legout, Arnaud
    INRIA, FRANCE.
    Small-world Streaming: Network-aware Streaming Overlay Construction Policies for a Flat Internet2011Manuscript (preprint) (Other academic)
    Abstract [en]

    Recent measurements indicate that the peering agreements betweenAutonomous Systems (AS) are flattening the AS level topology of theInternet. The transition to a more flat AS topology opens up for newpossibilities for proximity-aware peer-to-peer overlay construction. Inthis paper we consider the problem of the construction of overlays  forlive peer-to-peer streaming  that leverage peering connections tothe maximum extent possible, and investigate how a limited number ofoverlay connections over transit links should be chosen such as tomaximize the streaming performance. We define a set of transit overlaylink establishment policies that leverage topological characteristics ofthe AS graph. We evaluate their performance over regular AS topologiesusing extensive simulations, and show that the performance difference between the policies can be up to an order of magnitude. Thus, it is possible to maximize the system performance by leveraging the characteristics of the AS graph. Based on our results we also argue that the average loss probability is not an adequate measure of the performance of proximity-aware overlays.  We confirm our findings via simulations over a graph of the peering AS topology of over 600 ASs obtained from a large measurement data set.

  • 8.
    Chatzidrossos, Ilias
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktória
    KTH, School of Electrical Engineering (EES), Communication Networks.
    On the effect of free-riders in P2P streaming systems2008In: 2008 4TH INTERNATIONAL TELECOMMUNICATION NETWORKING WORKSHOP ON QOS IN MULTISERVICE IP NETWORKS, 2008, p. 8-13Conference paper (Refereed)
    Abstract [en]

    Peer-to-peer applications exploit the users willingness to contribute with their upload transmission capacity, achieving this way a scalable system where the available transmission capacity increases with the number of participating users. Since not all the users can offer upload capacity with high bitrate and reliability, it is of interest to see how these non-contributing users can be supported by a peer-to-peer application. In this paper we investigate how free-riders, that is, non-contributing users can be served in a peer-to-peer streaming system. We consider different policies of dealing with free-riders and discuss how performance parameters such as blocking and disconnection of free-riders are influenced by these policies, the overlay structure and system parameters as overlay size and source upload capacity. The results show that while the multiple-tree structure may affect the performance free-riders receive, the utilization of the transmission resources is still comparable to that of an optimized overlay.

  • 9.
    Dán, György
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Carlsson, Niklas
    Linköping University.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Efficient and Highly Available Peer Discovery: A Case for Independent Trackers and Gossiping2011In: IEEE Conference on Peer-to-peer Computing, IEEE , 2011, p. 290-299Conference paper (Refereed)
    Abstract [en]

    Abstract—Tracker-based peer-discovery is used in most commercial peer-to-peer content distribution systems, as it provides performance benefits compared to distributed solutions, and facilitates the control and monitoring of the overlay. But a tracker is a central point of failure, and its deployment and maintenance incur costs; hence an important question is how high tracker availability can be achieved at low cost. We investigate highly available, low overhead peer discovery, using independent trackers and a simple gossip protocol. This work is a step towards understanding the trade-off between the overhead and the achievable peer connectivity in highly available distributed overlay-management systems for peer-to-peer content distribution. We propose two protocols that connect peers in different swarms efficiently with a constant, but tunable, overhead. The two protocols, Random Peer Migration (RPM) and Random Multi-Tracking (RMT), employ a small fraction of peers in a torrent to virtually increase the size of swarms. We develop analytical models of the protocols based on renewal theory, and validate the models using both extensive simulations and controlled experiments. We illustrate the potential value of the protocols using large-scale measurement data that contains hundreds of thousands of public torrents with several small swarms, with limited peer connectivity. We estimate the achievable gains to be up to 40% on average for small torrents.

  • 10.
    Dán, György
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Chatzidrossos, Illias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktoria
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Karlsson, Gunnar
    KTH, School of Electrical Engineering (EES), Communication Networks.
    On the performance of error-resilient end-point-based multicast streaming2006In: 2006 14TH IEEE INTERNATIONAL WORKSHOP ON QUALITY OF SERVICE, PROCEEDINGS, 2006, p. 160-168Conference paper (Refereed)
    Abstract [en]

    In this paper we propose an analytical model of a resilient end-node multicast streaming architecture based on multiple minimum-depth-trees that employs path diversity and forward error correction for improved resilience to node churns and packet losses. We study the performance of the architecture in the presence of packet losses and dynamic node behavior. We show that for a given redundancy the probability that an arbitrary node possesses a packet is high as long as the loss probability in the network is below a certain threshold. After reaching the threshold the packet possession probability suddenly drops; the rate decrease gets faster as the number of nodes in the overlay grows. The value of the threshold depends on the ratio of redundancy and on the number of the distribution trees. We study the overlay structure in the presence of node dynamics and conclude that stability can be achieved only if the root node serves a large number of nodes simultaneously.

  • 11.
    Dán, György
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktória
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    On the performance of multiple-tree-based peer-to-peer live streaming2007In: INFOCOM 2007, VOLS 1-5, 2007, p. 2556-2560Conference paper (Refereed)
    Abstract [en]

    In this paper we propose and analyze a generalized multiple-tree-based overlay architecture for peer-to-peer live streaming that employs multipath transmission and forward error correction. We give mathematical models to describe the stability properties of the overlay and evaluate the error recovery in the presence of node dynamics and packet losses. We show how the stability of the overlay improves with the proper allocation of the outgoing bandwidths of the peers among the trees without compromising its error correcting capability.

  • 12.
    Dán, György
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktória
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Streaming performance in multiple-tree-based overlays2007In: NETWORKING 2007: Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet, Proceedings / [ed] Akyildiz, IF; Sivakumar, R; Ekici, E; DeOliveira, JC; McNair, J, 2007, p. 617-627Conference paper (Refereed)
    Abstract [en]

    In this paper we evaluate the data transmission performance of a generalized multiple-tree-based overlay architecture for peer-to-peer live streaming that employs multipath transmission and forward error correction. We give mathematical models to describe the error recovery in the presence of packet losses. We evaluate the data distribution performance of the overlay, its asymptotic behavior, the stability regions for the data transmission, and analyze the system behavior around the stability threshold. We argue that the composed measure of the mean and the variance of the packet possession probability can support adaptive forward error correction.

  • 13.
    Fodor, Viktória
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Communication Networks.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Playback delay in mesh-based peer-to-peer systems with random packet forwarding2008In: NGMAST 2008: SECOND INTERNATIONAL CONFERENCE ON NEXT GENERATION MOBILE APPLICATIONS, SERVICES, AND TECHNOLOGIES, PROCEEDINGS / [ed] AlBegain K; Cuevas A, LOS ALAMITOS: IEEE COMPUTER SOC , 2008, p. 550-555Conference paper (Refereed)
    Abstract [en]

    In meshed-based peer-to-peer streaming systems peers forward packets to their neighbors based on local scheduling decisions. The local decisions affect how packets get distributed in the mesh, the probability of duplicates and the distribution of the transmission delays. In this paper we propose an analytic framework that allows the evaluation of various scheduling algorithms. We consider two solutions where scheduling is performed at the forwarding peer, based on the knowledge of the playout buffer content at the neighbors. We evaluate the effectiveness of the solutions in terms of the probability that a peer can play out a packet versus the playback delay, and the scalability of the solutions with respect to the size of the overlay.

  • 14.
    Fodor, Viktória
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Communication Networks.
    Chatzidrossos, Ilias
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Playback delay in mesh-based peer-to-peer systems with random packet forwarding and transmission capacity limitations2008In: International Journal of Internet Protocol Technology, ISSN 1743-8209, Vol. 3, no 4, p. 257-265Article in journal (Refereed)
    Abstract [en]

    In meshed-based peer-to-peer streaming systems peers forward packets to their neighbours based on local scheduling decisions. The local decisions affect how packets get distributed in the mesh and consequently the distribution of the transmission delays. We propose an analytic framework that allows the evaluation of various scheduling algorithms. Two solutions are considered where scheduling is performed at the forwarding peer. We evaluate the effectiveness of the solutions in terms of the probability that a peer can play out a packet vs. the playback delay, and the scalability of the solutions with respect to the size of the overlay. Finally we discuss the effects of limited download bandwidth on the data dissemination.

1 - 14 of 14
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf