PUBLIC PEER-TO-PEER FILESHARING NETWORKS’ EVALUATION J. Lloret Mauri1, B. Molina Moreno2, C. Palau Salvador3, M. Esteve Domingo4 Department of Communications, Polytechnic University of Valencia Camino Vera s/n, Valencia, Spain [email protected], [email protected], [email protected], [email protected] ABSTRACT • Download speed: some internal P2P network, due to Since the recent appearance of P2P file-sharing networks, its internal behaviour, are optimal for downloading many Internet users have chosen this technology to search files of reduced size. Others, however, use for programs, films, songs, etc. Their number of users is multisplitting mechanisms and permit the download growing every day due to the attractive and interesting from multiple sources, making them suitable for content type that can be found and downloaded over these obtaining larger files. networks. In this article six public architectures are analyzed, Gnutella, FastTrack, Opennap, Edonkey, MP2P These parameters are responsible for an architecture and Soulseek, tracking their evolution during a week in becoming very popular or, on the other hand, terms of connected users, number of files and size of disappearing. The above factors can make a P2P network shared files per hour. The results will be compared and more attractive to users of a specific nation due to the discussed with previous measurements taken a year ago. utilization of a specific language or even social trends [7]. These data can be used to design new network models, to It is also interesting to distinguish between a P2P network calculate their performance or to optimize new network and P2P client, the development of which must not be parameters. necessarily parallel. If a P2P client changes its P2P network, all its community users will remain using it. As KEY WORDS an example, many users have remained ‘loyal’ to the Peer-To-Peer, Evaluation, Filesharing Networks. Morpheus P2P client throughout its evolution. Sometimes the reason for changing to another newly offered P2P 1. Introduction client is its ability to simultaneously contact several networks, such as Shareaza [8] and MLDonkey [9]. Since Internet became accessible to the world, the volume of connected users has been growing up in spectacular Due to the significant social impact of P2P file-sharing fashion. Recently, the number of Internet users is networks, both industry and academia are spending time estimated to be over 580 millions with a steady growth and money analyzing several aspects of these rate of 4% [1]. In the last years, Internet has sufficiently architectures. Probably the first considerations are the matured to catch market’s attention both at home and legality of the files that are being shared [10] and the enterprise level. Besides, the recent transition to potential risks that are running both home users [11] and broadband access networks, with a current amount of 40 industry with workers using their workstations as P2P million of users worldwide [2] allows multimedia clients [12]. Furthermore, most P2P networks have not services. been designed to address security issues (authentication, file permissions and file integrity); some P2P clients even P2P filesharing is one of the P2P variants with a large include addware or spyware. Moreover, as files are often number of supporters. Many users merely interact with downloaded from unknown users, they may include some this P2P network to download files without providing any, viruses or trojans inside the files. but there are many others with the intention to share their files with the whole community without caring about the Some ISPs have observed that their networks became person who is downloading them. Those who share files rapidly congested and sometimes P2P traffic reached often have a broadband always-on connection. There are nearly 60% of the total traffic [13]. Although not so many P2P public architectures; some of them are already striking, Internet2 administrators also computed relatively old, such as Gnutella [3], FastTrack [4] and impressive results on 16 February 2004 where 10.46% of OpenNap [5], whilst others are relatively new as is the the total traffic was originated by P2P file-sharing [14]. case of BitTorrent [6]. The success of a P2P network CAIDA (Cooperative Association for Internet Data inside a user community is determined by several factors: Analysis) also shows that Internet traffic is mainly dominated by P2P file-sharing protocols and HTTP [15]. • Simplicity: a P2P network with a graphical and easy- Some articles show the average number of connected to-use P2P is always welcome. users in some architecture [16] and, sometimes, even the • Language: a P2P client with multilanguage support maximum number of users. For example, Napster reached allows a broader deployment among world wide. the number of 20 million connected users with 1,5 billion of shared files in July 2000 [17]. Other studies focus their random events such as a sudden disconnection of a attention on P2P Instant Messaging and other fields of neighbor node, whose impact is considerable and P2P development. Some papers even study the economic measurable. The total number of on-line Gnutella users cost of downloading a file analyzing the required time has been decreasing continually, from 500.000 users on [18]. The manner in which the number of connected users April 2002 to about 110.000 users on October 2003. Since is calculated is sometimes deceptive if it is solely based that date it has been increasing again to a maximum of on the amount of users that download a certain client 300.000 users in April 2004 [28]. program for a P2P architecture [11, 12]. 2.1.2. FastTrack. This architecture is the one with most In Section 2 the architectures are characterized through users and shared data. As shown on Figure 2, which starts some parameters, such as number of users, shared files on a Friday, it has a waveform whose peaks are located and total size of shared information. These values are between 20:00 and 23:00 this corresponds with USA compared and discussed with those obtained a year ago. afternoon, as it is the country that mostly contributes in the number of users. Low values of the graph are timely 2. Measurements and analysis of the associated to a USA night. The average number of architectures connected users is 3.467.918, with a maximum value of 4.178.674 and a minimum value of 2.728.360, thus In order to measure P2P parameters, we have taken one characterized through a greatest fluctuation of 21,33%. totally decentralized architecture (Gnutella [3]) and four Between February and March 2003 the FastTrack partially decentralized architectures (FastTrack [4], architecture had an average number of connected users of OpenNap [5], eDonkey [19, 20] and MP2P [21]) and a 3.897.015, with a maximum of 4.585.549 and a minimum centralized architecture (SoulSeek [22]). For the purpose of 3.328.813. Hence it follows that the number of users of this article we took measurements between February has decreased about 11%. The possible reason for that is and March 2003 for the Gnutella, FastTrack, OpenNap the creation of new P2P networks that attract users from and eDonkey architectures. Later on, we measured the older architectures. The FastTrack graph does not reveal same parameters between November 2003 and February any significant appreciation between normal working 2004. This time, however, the MP2P and SoulSeek days and weekends. architectures were also analyzed due to the increment in the number of users that they were experiencing. All the 2.1.3. OpenNap. Figure 3 shows the number of on-line Figures correspond to the most significant ones amongst users during a week, starting on a Thursday. The average all obtained data. All time values are GMT+01:00 number of simultaneously connected users is 256.003 timezone. with upper and lower limits of 376.378 and 182.188 respectively, and a highest fluctuation of 42,02%. The To take measurements of the corresponding architectures, obtained graph is very irregular. Taking each day as the most adequate clients have been selected, bearing in independent, we observe that low values of connected mind those that would provide the most information on users are obtained at night (between 0:00 and 4:00) the architecture or the highest update frequency to whereas high values are located between 18:00 and 22:00. measure the parameters. The Gnutella architecture has The main peaks are located on weekends. Comparing the been analyzed with the Limewire client [23], which has above results with those obtained a year before (between been set up with a TTL value of seven. This is the reason February and March 2003) the average number of on-line why the number of users, files and size of shared data is users in the OpenNap architecture was 395.853 with a relatively low. In the FastTrack architecture, the maximum of 463.210 and a minimum of 357.382. We can measurements have been taken with the KaZaA Lite note a decrease of 35 %. The main reason is probably that client [24]. In order to analyze OpenNap architecture, the some users have migrated to other P2P networks. Napigator client [25] has been used. The eMule client [26] has been utilized to analyze the Edonkey 2.1.4. eDonkey. Figure 4 illustrates the number of architecture. The MP2P architecture has been analyzed by connected users during a week, starting on a Monday. The means of the Blubster client [21]. Finally it has been used average number of on-line users has a value of 1.428.175 the Nicotine [27] client in order to analyze the SoulSeek and the upper and low variation margins are 1.718.201 architecture.