Problemområde: Idag är användandet av peer-to-peer (P2P) - applikationer såsom KaZaa, ICQ och Seti@home utbrett bland privatpersoner. Användningen inom företag är dock ännu i sin linda. Vi kommer därför i den här uppsatsen utreda om ett eventuellt införande av P2P- teknik i ett företagsnätverk ger några fördelar jämfört med en klassisk Client/Server-lösning. Hypotes: Arbetet bygger på hypotesen: ?En P2P-lösning ger fördelar för företaget jämfört med en Client/Server-lösning? Genomförande: För jämförelsen mellan P2P och Client/Server definierades och jämfördes fem områden: Säkerhet, Användbarhet, Tillgänglighet, Bandbredd samt Utrustningskrav. Slutsats: Inom områdena Användbarhet och Tillgänglighet ger en P2P-lösning klara fördelar, däremot inom områdena Säkerhet och Bandbredd visar Client/Server- lösningen istället klara fördelar. Området Utrustningskrav är oavgjort då det inte finns någon märkbar skillnad på lösningarna. Säkerhetsproblemen är P2P-teknologins akilleshäl och det problem som är mest troligt att stoppa stora investeringar i framtiden om det inte löses. Slutsatsen av vår jämförelse blir sålunda: För ett företag som redan har ett existerande Client/Server-nätverk är det inte någon idé att helt byta system, däremot kan det vara av intresse att introducera en applikation som möjliggör skapandet av så kallade Virtuella Nätverk. För ett helt nytt företag kan skapandet av ett P2P-nätverk vara ett väl så intressant alternativ till Client/Server. Detta förutsätter dock att säkerheten inte är så viktig för företaget eller att säkerhetsproblemen lösts.

Peer-to-Peer (P2P) tools are used exclusively when their users are connected to the Internet, thus constituting a good foundation for online commercials to help finance further tool development. Although software that displays ads (adware) is very common, activity monitoring or information collecting software that spies on the users (spyware) may be installed together with the P2P tool. This paper will present a method for examining P2P tool installations and present test results from a few of the most common P2P tools. It will also discuss whether these tools, with their bundled software, make any privacy intrusions. Finally, the method itself will be evaluated and suggestions of refinements will be proposed.

Peer-to-peer (P2P) applications have become a popular method for obtaining digital content. Recent research has shown that the amount of time spent downloading from a poor performing peer effects the total download duration. Current peer selection strategies attempt to limit the amount of time spent downloading from a poor performing peer, but they do not use both advanced knowledge and service capacity after the connection has been made to aid in peer selection. Advanced knowledge has traditionally been obtained from methods that add additional overhead to the P2P network, such as polling peers for service capacity information, using round trip time techniques to calculate the distance between peers, and by using tracker peers. This work investigated the creation of a new download strategy that replaced the random selection of peers with a method that selects server peers based on historic service capacity and ISP in order to further reduce the amount of time needed to complete a download session. Peer-to-peer (P2P) applications have become a popular method for obtaining digital content. Recent research has shown that the amount of time spent downloading from a poor performing peer effects the total download duration. Current peer selection strategies attempt to limit the amount of time spent downloading from a poor performing peer, but they do not use both advanced knowledge and service capacity after the connection has been made to aid in peer selection. Advanced knowledge has traditionally been obtained from methods that add additional overhead to the P2P network, such as polling peers for service capacity information, using round trip time techniques to calculate the distance between peers, and by using tracker peers. This work investigated the creation of a new download strategy that replaced the random selection of peers with a method that selects server peers based on historic service capacity and ISP in order to further reduce the amount of time needed to complete a download session. The results of this new historic based peer selection strategy have shown that there are benefits in using advanced knowledge to select peers and only replacing the worst performing peers. This new approach showed an average download duration improvement of 16.6% in the single client simulation and an average cross ISP traffic reduction of 55.17% when ISPs were participating in cross ISP throttling. In the multiple clients simulation the new approach showed an average download duration improvement of 53.31% and an average cross ISP traffic reduction of 88.83% when ISPs were participating in cross ISP throttling. This new approach also significantly improved the consistency of the download duration between download sessions allowing for the more accurate prediction of download times.

A dissertation presented on distributed Peer-to-Peer (P2P) Internet applications, focusing on distributed resource sharing as a P2P application. The history of Internet applications is researched to point out the roots of P2P applications as well as the dependency between modern technology and legacy technology. P2P applications are compared with traditional client/server applications. A classification system for categorizing P2P applications according to functionality and computing model is devised. The classification system is used to group applications with similar attributes and behavior. Five main mechanisms utilized by all content sharing P2P applications are identified. These mechanisms are node discovery, content discovery, content retrieval, content publishing and content storage. Napster, Gnutella and Freenet are discussed in detail as examples of distributed P2P resource sharing applications which utilize these mechanisms. These applications are then compared to point out similarities and differences. Other P2P initiatives known to the author are briefly presented. Challenges that need to be overcome if P2Papplications are to be widely adopted are identified and discussed. A typical content sharing P2P application is implemented for constraint mobile devices such as cell phones. The unique characteristics, possibilities and challenges of P2P on mobile devices are explored. / Dissertation (MSc)--University of Pretoria, 2005. / Computer Science / unrestricted

When Napster was first launched on the Internet in August of 1999 by young programmer, Shawn Fanning, the intension was that the platform would easily link Internet users with the free MP3 downloads they sought out on the web. By the time an injunction against the platform was granted and upheld by a state then federal court, Napster had made a far bigger impact than simply linking music listeners with free downloads. The proceedings of A & M Records, Inc. v. Napster, Inc. through the District Court Northern District of California then the United States Court of Appeals for the Ninth Circuit acted to test the applicability of copyright protections that had been legislatively heightened throughout the 1990’s and built the framework for specifications for copyright protection on the Internet. Even after fifteen years of being offline, the peer-to-peer platform still remains a household name due to the influence Napster had on shaping music consumers’ expectations of access to digital music as well as distributors’ practices. Through a review of A & M Records, Inc. v. Napster, Inc. in the district and appellate courts I will explore the workings of the Napster platform and the legal issues surrounding it - with an emphasis on vicarious copyright infringement, contributory copyright infringement, the application of the DMCA, and the application of the substantial non-infringing use doctrine to software technologies, as established by Sony Corporation of America v. Universal City Studios, Inc. I conclude that Napster has had a resounding legal, psychological, and technical impact on both the distribution and consumption of music in the digital space.

We present an architecture for a fully decentralized peer-to-peer collaborative computing platform, offering services similar to Cloud Service Provider’s Platform-as-a-Service (PaaS) model, using volunteered resources rather than dedicated resources. This thesis is motivated by three research questions: (1) Is it possible to build a peer-to-peer col- laborative system using a fully decentralized infrastructure relying only on volunteered resources?, (2) How can light virtualization be used to mitigate the complexity inherent to the volunteered resources?, and (3) What are the minimal requirements for a computing platform similar to the PaaS cloud computing platform? We propose an architecture composed of three layers: the Network layer, the Virtual layer, and the Application layer. We also propose to use light virtualization technologies, or containers, to provide a uniform abstraction of the contributing resources and to isolate the host environment from the contributed environment. Then, we propose a minimal API specification for this computing platform, which is also applicable to PaaS computing platforms. The findings of this thesis corroborate the hypothesis that peer-to-peer collaborative systems can be used as a basis for developing volunteer cloud computing infrastructures. We outline the implications of using light virtualization as an integral virtualization primitive in public distributed computing platform. Finally, this thesis lays out a starting point for most volunteer cloud computing infrastructure development effort, because it circumscribes the essential requirements and presents solutions to mitigate the complexities inherent to this paradigm.

Peer-to-Peer-Finanzierungen haben in den letzten Jahren nicht nur aufgrund ihres disruptiven Charakters, sondern auch aufgrund ihres raschen Wachstums und der wachsenden Bandbreite an Dienstleistungen zunehmend Beachtung gefunden. Peer-to-Peer Kreditplattformen versuchen, Banken zu umgehen, um Kreditnehmern eine Alternative und Anlegern eine neue Anlageklasse anzubieten - wird dies zu einem „Banking ohne Banken“ führen? Peer-to-Peer Betreiber müssen darauf achten, dass sie ihre Geschäfte gemäß den geltenden Gesetzen und Vorschriften planen und betreiben, auch wenn sie mit einer Bank zusammenarbeiten, die als Kreditgeber fungiert, da die Nichteinhaltung der geltenden Vorschriften unter anderem zivil- und strafrechtliche Sanktionen, Prozesskosten sowie nachteilige Publizität und im schlimmsten Fall die Beendigung des Geschäfts nach sich ziehen kann. Zusätzliche Schwierigkeiten ergeben sich aufgrund unterschiedlicher Vorschriften in den europäischen Ländern. Infolgedessen muss eine neue Beurteilung des rechtlichen Umfelds vorgenommen werden, bevor ein Peer-to-Peer Betreiber sein Geschäft auf andere Länder ausweiten kann, was häufig zu unterschiedlichen Konfigurationen und Geschäftsmodellen führt. In dieser Dissertation sollen die wichtigsten Bestimmungen für die Vergabe von Peer-to-Peer Krediten herausgearbeitet werden. Der Schwerpunkt liegt auf den rechtlichen Rahmenbedingungen für Peer-to-Peer Kredite in Deutschland, d.h. welche Vorschriften diese Plattformen erfüllen müssen, um ihr Geschäftsmodell zu betreiben, und/ oder welche Vorschriften und Lizenzanforderungen für diese Unternehmen gelten. Zunächst wird erklärt, was Peer-to-Peer Kredite sind, wie sie sich entwickelt haben und wie sie funktionieren. Die rechtlichen Rahmenbedingungen werden sowohl für Deutschland als auch für europäische Länder, nämlich das Vereinigte Königreich, Schweden und die Niederlande, im Vergleich untersucht. Anschließend wird untersucht, warum verschiedene europäische Länder unterschiedliche Regeln anwenden und ob es möglich wäre, solche Regelungen für Peer-to-Peer Kredite in ganz Europa zu harmonisieren und gleichzeitig sicherzustellen, dass die Hauptgründe der Länder erfüllt werden. / Peer-to-peer finance has received increasing attention over the last years, not only because of its disruptive nature, but also because of its rapid growth and expanding breadth of services. Peer-to-peer lending platforms try to circumvent banks to offer borrowers an alternative and investors a new asset class – will this lead to a “Banking without banks”. Peer-to-peer operators need to be careful to plan and operate their business in compliance with applicable laws and regulations, even if they cooperate with a non-affiliated bank that acts as lender of record, since failure to comply with applicable regulations can result in, among others, civil and criminal penalties, litigation expenses as well as adverse publicity and in the worst case the termination of the business. Additional difficulties arise due to different regulations across European countries. Consequently a new assessment of the legal environment needs to be made before a peer-to-peer operator can expand its business into other countries and often leads to differing setups and business models. The dissertation is intended to identify principal regulations that apply to peer-to-peer lending. The focus lies on the legal framework for peer-to-peer lending in Germany, i.e. which regulations such platforms have to comply with in order to operate their business model and/or which regulations are applicable to such businesses and which license requirements apply. First of all it will be explained what peer-to-peer lending is, how it evolved and how it works. The legal framework will be investigated with regards to Germany as well as European countries, namely the United Kingdom, Sweden and the Netherlands, in comparison. It will then be examined why different European countries apply different rules and whether it would be possible to harmonise such regulations for peer-to-peer lending across Europe whilst ensuring that the countries’ main rationales are fulfilled.

In this paper, we consider the peer-to-peer transfer of popular files between devices in a wireless mesh network. We address the problem that occurs when multiple nodes try to access the same file simultaneously, resulting in increased contention on the shared wireless channel. To counteract this problem, we propose a cooperative file transfer protocol which splits a file into fixed-sized pieces and allows simultaneous downloads of such pieces from multiple peers. Opposed to previous approaches, the proposed protocol selects the potential download peers such that the corresponding download paths possess minimum interference among each other. In a performance study where we compare our approach with other download schemes proposed in the literature, we show that our cooperative protocol roughly halves the time required for downloading a file.

In recent years dramatic technology developments have exploited the development of better transmission media and allowed for broad internet penetration. This in turn has fostered the growth of IP telephony calls, i.e., Voice over IP (VoIP). New VoIP products are introduced almost daily, each seeking an opportunity in the market. Some of these products are free - thus putting pressure on other vendors. A good example of a commercial VoIP product is Skype. It is possibly the most important one as it has gained more than 3 millions users in approximately 2 years time. In contrast, Minisip is a non-commercial implementation of SIP developed by students at KTH. These programs are based on different architectures. While Skype is said to be based on a peer-to-peer protocol, Minisip utilized the Session Initiation Protocol (SIP) protocol. The aim of this thesis was to evaluate these two VoIP programs not only in terms of development, but also in terms of the quality of service and user perceived voice quality. The study of efficiency, usability, and installation of both are also in the scope of this thesis. The devices used for the evaluation included a HP iPAQ 5550, two PCs running in RedHat Linux 9, and a laptop running Microsoft Windows XP. / På senare år har den dramatiska teknikutvecklingen exploaterat utvecklingen av bättre överföringsmedia samt möjliggjort för en bred Internetpenetrering. Det i sin tur har gynnat ökningen av telefonsamtal med IP-telefoner, d.v.s. Voice over IP (VoIP). Nya VoIP produkter introduceras nästan dagligen och varje produkt söker sin möjlighet på marknaden. Vissa av dessa produkter är gratis och sätter alltså press på andra försäljarna. Ett bra exempel på en VoIP produkt är Skype. Det är möjligtvis den viktigaste produkten då den har fått tre miljoner användare på ungefär två års tid. I kontrast till detta finns Minisip som är en icke kommersiell implementation av SIP, utvecklad av studenter från KTH. Dessa program är baserade på olika arkitekturer. Medan Skype är baserat på ett peer-to-peer protokoll, utnyttjar Minisip protokollet Session Initiation Protocol (SIP) Protocol. Syftet med denna avhandling var att evaluera dessa två VoIP program, inte bara i termer av utveckling utan också i termer av ”quality of service” och hur användaren uppfattar röstkvaliteten. Studien innefattar också effektivitet, användarvänlighet och installation av de båda programmen. Enheterna som användes under denna evaluering var en HP iPAQ 5550, två pc:s med Linux Red Hat 9 samt en bärbar pc med Windows XP.

IPTV is gaining increasing attention. It is an expanding field where a lot of people are working hard to solve the problems that delay its wide-spread use. One major problem is that the existing IPTV distribution mechanisms do not seem to work well when applied on a large scale. Especially, IP multicast does not seem to meet the requirements of highly demanding IPTV services. In contrast, peer-to-peer architectures for distributing content have been available for a number of years (since the late 1990’s), and their success suggests that this is a promising alternative means of distributing content. Although peer-to-peer architectures are well known for file transfer, this kind of architecture has been used in this thesis for distributing streaming video flows. We combine results from two different approaches - IPTV and peer-to-peer systems - as part of our design and implementation of a new solution for distributing IPTV. Our proposal aims to avoid any weaknesses that the existing solutions have, whilst offering a viable solution for distributing live content. / Intresset kring IPTV ökar hela tiden, och många människor arbetar på att lösa de problem som hindrar området från att växa snabbt. Ett av huvudproblemen är att den existerande IPTV-distributionstekniken inte fungerar bra då den appliceras på stora lösningar. Bland de största problemen är att IP-Multicast inte möter de krav som marknaden ställer på global distribution av material. I motsats till detta har peer-to-peer teknik, som funnits sedan 90-talet, visat sin styrka för fil distribution på en mycket global skala på existerande infrastruktur. I denna uppstats kombinerar vi dessa två områden för att utröna vilka möjligheterna som finns för att optimera kostnaden för distrubition av live-tv samtidigt som vi försöker att undvika de svagheter som normalt associeras med de olika arkitekturerna. Vårt mål är att utnyttja de bästa egenskaperna från de olika teknikerna för att skapa en livsduglig och långsiktig lösning för TV-distribution.