With the development of Internet, more and more people believe that the future telecommunication network will be constructed based on IP technology. Session Initiation Protocol (SIP), which has advantages of simple entrainment method, good scalability and open protocols, is the main research topic on Voice-over-IP (VoIP). Although the client-server architecture currently used by SIP is simple and easy to maintain, it has limitation wherein service quality needs to rely on server performance. To improve this, the Internet Engineering Task Force (IETF) has created a draft to discuss the application of P2P (Peer-to-Peer) architecture in SIP, and we hope that the draft can help to provide good SIP service quality on P2P architecture, such as good fault tolerance and transmission performance. Our research is based on Chord architecture and aims to make P2P SIP architecture in an embedded User Agent. For the SIP internet telephone feature, we adjusts Chord algorithm to meet SIP internet telephone requirements. Furthermore, the adjustment to Chord makes it more applicable to the environment that users continuously join or leave, so that the revised Chord can be implemented with SIP protocol to achieve the P2P SIP goal.

The rapid growth of peer-to-peer (P2P) networks in the past few years has brought with it increases in transit cost to Internet Service Providers (ISPs), as peers exchange large amounts of traffic across ISP boundaries. This ISP oblivious behavior has resulted in misalignment of incentives between P2P networks|that seek to maximize user quality|and ISPs|that would seek to minimize costs. Can we design a P2P overlay that accounts for both ISP costs as well as quality of service, and attains a desired tradeoff between the two? We design a system, which we call MultiTrack, that consists of an overlay of multiple kinds of Trackers whose purpose it is to align these goals. We have mTrackers that form an overlay network among themselves, and split demand from users among different ISP domains while trying to minimize their individual costs (delay plus transit cost) in their ISP domain. We design the signals in this overlay of mTrackers in such a way that potentially competitive individual optimization goals are aligned across the mTrackers. The system could also have a tTracker that acts as a gateway into the system, and ensures that users who are from different ISP domains have a fair chance of being admitted into the system, while keeping costs in check. We prove analytically that our system is stable and achieves maximum utility with minimum cost. We validated our system design using Matlab simulations, and implemented the system on ns-2 in order to conduct more realistic experiments. We showed that our system significantly outperforms two types of systems, one in which user delay is the only control dimension (forwarding traffic without considering the transit prices) and a second system in which transit prices are the only control dimension (localized traffic only). Thus, we conclude that our system, that operates in two dimensions: (1) user delay and (2) transit prices, results in minimum cost and maximum utility for fixed capacity of the system.

Peer-to-peer technologies have shown a lot of promise in sharing the remote resources effectively. The resources shared by peers are information, bandwidth, storage space or the computing power. When used properly, they can prove to be very advantageous as they scale well, are dynamic, autonomous, fully distributed and can exploit the heterogeneity of peers effectively. They provide an efficient infrastructure for an application seeking to distribute numerical computation. In this thesis, we investigate the feasibility of using a peer-to-peer infrastructure to distribute the computational load of Matlab and similar applications to achieve performance benefits and scalability. We also develop a proof of concept application to distribute the computation of a Matlab style application.

Over the last few years, peer-to-peer (P2P) applications have relentlessly grown to represent a formidable component of Internet traffic. In contract to P2P networks witch used well-defined port number, current P2P applications have use of arbitrary ports. As P2P applications continue to evolve, robust and effective methods are methods are needed for P2P traffic identification. Many P2P applications are bandwidth-intensive. Understanding the Internet traffic profile is important for several reasons, including traffic engineering, network service pricing. In this Thesis, we integrated port-based method into original Classifier which is using content-based method only. Therefore, we can improve the recognition rate for Classifier and identify more applications. We also verified our Classifier recognition rate by using the results of Service Control Engine.

In a video-on-demand streaming system, each user watch dufferent video frame according to their arrival time. In the thesis, the concept of multi-source and the forward error correction scheme are implemented to decrease the workload bandwidth of server and reduce the packet loss probability of each peer in the peer-to-peer video-on-demand system. Here, in order to share data to some peers arrive later, each peer must cache part of video data that recently viewed. Each new arrival peer needs to contact multiple sources who have initial part of video data to get video streaming data, and each source transmits different part of video streaming. Once receiving all of these partial stream, the peer will get completely video data. Simulation shows that a suitable preserve time of peers in the system can be used. Thus, the workload bandwidth of server used and memory used by peers can be reduced, too. Furthermore, the packet loss probability is decreased by the sources diversity and the FEC recovery.

Due to the fast growing bandwidth of Internet users, the P2P video streaming on the Internet becomes one of impaortant solutions to release the traffic load. However, the current studies fall short of addressing the video delay issue on live P2P streaming. In this research, we proposed a topology construction method: Smart-Fit, towards minimizing the transmission delay between users and video server. The concept is based on minimizing the hop counts between server and users, in further to reduce the delay. With the bandwidth variety of Internet users, the proppsed method builds a predicted ideal template. Then the users¡¦ joining and leaving behaviors and the system¡¦s topology are constructed according to the template. Simulation results show the proposed method successfully reduces the hop count and the transmission delay between users and server. Moreover, due to the reduction of hop count, the packet loss rate is also reduced.

To provide interactive operations such as fast-forward, slow-forward, switch channel, and jump function for peer-to-peer on demand video streaming is a challenge. In this thesis, we proposed a vEB-tree (van Emde Boas tree) based architecture for interactive VoD services in peer-to-peer networks. The proposed architecture assumes videos can be divided into many segments, and these segments are stored in each peer. In the architecture, it includes vEB-tree based topology, procedure of demand segment search, and a distribution scheme. It not only efficiently provides interactive operations but also reduces the control messages. Additionally, each peer stores segments based on the proposed distribution scheme to reduce the server stress. Experimental results demonstrate that the proposed architecture outperforms Baton, BBTU, and VMesh in terms of jump latency, server stress, and neighbors¡¦ maintenance cost.

<p>Fildelning har på sistone varit ett aktuellt ämne i media där den nya upphovsrättslagen har diskuterats för fullt. När den nya upphovsrättslagen infördes 1 juli 2005 i Sverige, skapades det ett intresse från vår sida att undersöka vilken inverkan den nya lagen skulle få och om den skulle lyckas minska fildelningen.</p><p>Denna teknik går till så att man delar med sig av sina filer (media till andra användare antingen genom Internet eller i ett nätverk. Genom att dela med sig av sina filer kan man själv få tillgång till andras filer. Men för att kunna fildela krävs det att man använder speciella fildelningsprogram som exempelvis Bittorrent, DC och Kazaa. Det som vi strävar efter med denna rapport är att se om lagen har påverkat fildelarnas attityd gentemot fildelning, men också hur den nya upphovsrättslagen har påverkat fildelningen idag.</p><p>I referensramen har vi tagit upp redan befintlig fakta (sekundär data) som vi anser relevant för forskningens syfte. Här vill vi att läsaren ska kunna sätta sig in i arbetet för att lättare förstå och få en överblick över fildelning och dess lag. Intresseorganisationen Antipiratbyrån har beskrivits kortfattat eftersom de är den största organisationen i Sverige som kämpar för att stoppa illegal fildelning men vi har också tagit upp lite om Piratbyrån som är för fildelning och är Antipiratbyråns största rival. Här har vi även tagit upp de två första fildelningsfallen i Sverige.</p><p>Vi har även samlat in primär data från olika tänkbara fildelare. En enkät har utvecklats som besvarades av 92 respondenter i åldrarna 16-35 år. De har delats ut i Jönköpings högskolor, Per Brahe gymnasiet samt på allmänna platser. Enkäten fokuserar på ämnet fildelning, men också på upphovsrättslagen och innehåller mest frågor med bestämda svarsalternativ men också några frågor med öppna svar, där respondenterna får svara med egna ord. Enkätundersökningen är av kvantitativ karaktär medan analysen av enkäterna är av kvalitativ karaktär.</p><p>Utifrån vår referensram, samt våra resultat från enkäten har vi försökt analysera dessa så gott det går och svarat på våra två forskningsfrågor.</p><p>Vi har kommit fram till att upphovsrättslagen inte fungerar tillräckligt bra. Genom enkäten har vi dragit slutsatsen till att ingen reducering av fildelning har skett. Av de många anmälningar som gjorts av Antipiratbyrån har också bara ett fåtal fall gått till domstol. För att upphovsrättslagen ska fungera bättre krävs det mer insatser för att stoppa fildelningen.</p>

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme der Fakultaet fuer Informatik der TU Chemnitz. Anhand des Freenet-Projektes wird erklärt, wie anonymes Filesharing funktioniert. Der Vortrag beschreibt den Aufbau und die Funktion von Freenet und wie man Daten in Freenet einspielt bzw. wiederfinden kann. Es werden Vor und Nachteile von Freenet gegenüber anderen Projekten genannt.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme der Fakultaet fuer Informatik der TU Chemnitz. Es wird ein Konzept zur verteilten Datensicherung auf potentiell unsicheren Klienten beschrieben.