I Know Where You are and What You are Sharing: Exploiting P2P Communications to Invade Users' Privacy

In this paper, we show how to exploit real-time communication applications to determine the IP address of a targeted user. We focus our study on Skype, although other real-time communication applications may have similar privacy issues. We first design a scheme that calls an identified targeted user inconspicuously to find his IP address, which can be done even if he is behind a NAT. By calling the user periodically, we can then observe the mobility of the user. We show how to scale the scheme to observe the mobility patterns of tens of thousands of users. We also consider the linkability threat, in which the identified user is linked to his Internet usage. We illustrate this threat by combining Skype and BitTorrent to show that it is possible to determine the file-sharing usage of identified users. We devise a scheme based on the identification field of the IP datagrams to verify with high accuracy whether the identified user is participating in specific torrents. We conclude that any Internet user can leverage Skype, and potentially other real-time communication systems, to observe the mobility and file-sharing usage of tens of millions of identified users.Comment: This is the authors' version of the ACM/USENIX Internet Measurement Conference (IMC) 2011 pape

CLOSER: A Collaborative Locality-aware Overlay SERvice

Current Peer-to-Peer (P2P) file sharing systems make use of a considerable percentage of Internet Service Providers (ISPs) bandwidth. This paper presents the Collaborative Locality-aware Overlay SERvice (CLOSER), an architecture that aims at lessening the usage of expensive international links by exploiting traffic locality (i.e., a resource is downloaded from the inside of the ISP whenever possible). The paper proves the effectiveness of CLOSER by analysis and simulation, also comparing this architecture with existing solutions for traffic locality in P2P systems. While savings on international links can be attractive for ISPs, it is necessary to offer some features that can be of interest for users to favor a wide adoption of the application. For this reason, CLOSER also introduces a privacy module that may arouse the users' interest and encourage them to switch to the new architectur

Study of Negative effects of Traffic Localization

Català: Les xarxes P2P s'han convertit en una important xarxa per usuaris i ISP. Els usuaris volen compartir i aprofitar aquestes noves xarxes. D'altra banda, els ISP no volen que els usuaris utilitzin de manera tan intensa les seves connexions a Internet. Això causa que els seus beneficis es redueixin. La localització de tràfic ha estat anunciat com una solució per als inconvenients del P2P. Redueix el tràfic intercanviat entre els usuaris fent clúster. Només uns pocs usuaris d'un cluster intercanviaren dades amb altres xarxes. Hi ha diversos estudis que mostren els beneficis d'aquesta mesura, però no hi ha massa estudis sobre els efectes negatius. En el nostre treball hem tractat de simular una xarxa BitTorrent. Un cop tinguem aquesta xarxa preparada simularem una xarxa que utilitzi tècniques de localització de trànsit. Fent diverses simulacions volem demostrar com la localització de trànsit afecta l'experiència dels usuaris.Castellano: Las redes P2P se han convertido en una importante red para usuarios e ISP. Los usuarios quieren compartir y aprovechar estas nuevas redes. Por otra parte, los ISP no les interesa que los usuarios utilicen de manera tan intensa sus conexiones. Esto es debido a que sus beneficios se ven reducidos. La localización de tráfico ha sido anunciada como una de las mejores soluciones para los inconvenientes del P2P. Reduce el tráfico intercambiado entre los usuarios lejanos o de diferentes redes haciendo clúster. Sólo unos pocos usuarios de un clúster van a intercambiar datos con otros usuarios de otras redes. Hay varios estudios que indican los beneficios de esta medida, pero no hay demasiados estudios acerca de los efectos negativos. En nuestro trabajo hemos tratado de simular una red BitTorrent. Una vez que tengamos esta red lista simularemos una red P2P con alguna técnica de localización de tráfico. Haciendo varias simulaciones queremos demostrar cómo la localización de tráfico afecta a la experiencia de los usuarios.English: P2P networks has become one important network for users and ISP. Users wants to share and take profit of this new networks. On the other hand, ISP don not want users' to use so intensively their internet connections because their profits are being reduced. Traffic Localization has been announced as a solution for P2P disadvantages. It reduces the traffic exchanged between users making cluster. Only a few users from one cluster are going to change data to other networks. There are several studies that indicates the benefits of this measure but there are not too much studies about negative effects. In our work we tried to simulate a BitTorrent network. Once we have this network ready we constructed it making clusters simulating some Traffic Localization technique. Making several simulations we want to prove how traffic localization affects users' experience

Design and implementation of locality-aware P2P system

One of the most relevant problem for an Internet Service Provider is the large bandwidth usage on international links, mainly due to peer-to-peer applications adopted for file-sharing. The Collaborative Locality-aware Overlay SERvice (CLOSER) technology has been recently proposed to solve this issue by properly modifying the behavior of peer-to-peer application. The technology is also covered in two recent patent applications. This paper presents possible design guidelines to actually implement CLOSER in a DHT-based peer-to-peer system and describe a real implementation based on the popular aMule applicatio

Reducing BitTorrent Download Time via Handshake-Based Switching

Peer-to-peer networking overcomes the single point of failure and bandwidth limitations inherent to the centralized server model of file-sharing. It is both a popular means of sharing digital content and a major consumer of internet traffic, with BitTorrent being the most-used protocol. As such, significant research has gone into improving peer-to-peer performance in order to reduce both download times and networking costs. One aspect that can affect performance is the client’s selection of peers to download from, as the time spent downloading from even a single poor-performing peer can impact the overall download duration. A recent peer selection strategy explored having a client use historical knowledge acquired through third-party sources, as well as its own first-hand experience with previously visited peers, as a means of selecting likely good-performers, coupled with a peer switching strategy that replaced peers whose post-selection downloads exhibited poor performance contrary to what historical knowledge suggested in order to limit the time spent downloading from said poor-performers Though this tactic demonstrated reduced download times compared to various past works, it still suffered from poor peer selection due to its historical knowledge not necessarily reflecting the current state of the peers. This work introduced and examined an enhancement to this hybrid peer selection and switching strategy by adding current intelligence regarding a peer’s available bandwidth, all the while avoiding the additional network costs associated with performing on-the-fly probing or querying techniques utilized by other peer selection strategies to benchmark prospective peers. With such on-the-fly knowledge about a peer’s current bandwidth availability, this new enhanced strategy quickly replaced poor performers without waiting for downloads to be performed and subsequently benchmarked, resulting in reduced overall peer-to-peer download times. The results of adding this pre-download peer switching enhancement demonstrated improved download performance, particularly in early file transfer runs. However, as more runs occurred and the benefits of the original strategy’s historical knowledge became more pronounced, the time savings gained from this new enhancement diminished

Study of Negative Effects of Traffic Localization

P2P networks has become one important network for users and ISP. Users wants to share and take profit of this new networks. On the other hand, ISP don not want users to use so intensively their internet connections because their profits are being reduced. Traffic Localization has been announced as a solution for P2P disadvantages. It reduces the traffic exchanged between users making cluster. Only a few users from one cluster are going to change data to other networks. There are several studies that indicates the benefits of this measure but there are not too much studies about negative effects. In our work we tried to simulate a BitTorrent network. Once we have this network ready we constructed it making clusters simulating some Traffic Localization technique. Making several simulations we want to prove how traffic localization affects users experience. /Kir1

Study of Negative effects of Traffic Localization

Català: Les xarxes P2P s'han convertit en una important xarxa per usuaris i ISP. Els usuaris volen compartir i aprofitar aquestes noves xarxes. D'altra banda, els ISP no volen que els usuaris utilitzin de manera tan intensa les seves connexions a Internet. Això causa que els seus beneficis es redueixin. La localització de tràfic ha estat anunciat com una solució per als inconvenients del P2P. Redueix el tràfic intercanviat entre els usuaris fent clúster. Només uns pocs usuaris d'un cluster intercanviaren dades amb altres xarxes. Hi ha diversos estudis que mostren els beneficis d'aquesta mesura, però no hi ha massa estudis sobre els efectes negatius. En el nostre treball hem tractat de simular una xarxa BitTorrent. Un cop tinguem aquesta xarxa preparada simularem una xarxa que utilitzi tècniques de localització de trànsit. Fent diverses simulacions volem demostrar com la localització de trànsit afecta l'experiència dels usuaris.Castellano: Las redes P2P se han convertido en una importante red para usuarios e ISP. Los usuarios quieren compartir y aprovechar estas nuevas redes. Por otra parte, los ISP no les interesa que los usuarios utilicen de manera tan intensa sus conexiones. Esto es debido a que sus beneficios se ven reducidos. La localización de tráfico ha sido anunciada como una de las mejores soluciones para los inconvenientes del P2P. Reduce el tráfico intercambiado entre los usuarios lejanos o de diferentes redes haciendo clúster. Sólo unos pocos usuarios de un clúster van a intercambiar datos con otros usuarios de otras redes. Hay varios estudios que indican los beneficios de esta medida, pero no hay demasiados estudios acerca de los efectos negativos. En nuestro trabajo hemos tratado de simular una red BitTorrent. Una vez que tengamos esta red lista simularemos una red P2P con alguna técnica de localización de tráfico. Haciendo varias simulaciones queremos demostrar cómo la localización de tráfico afecta a la experiencia de los usuarios.English: P2P networks has become one important network for users and ISP. Users wants to share and take profit of this new networks. On the other hand, ISP don not want users' to use so intensively their internet connections because their profits are being reduced. Traffic Localization has been announced as a solution for P2P disadvantages. It reduces the traffic exchanged between users making cluster. Only a few users from one cluster are going to change data to other networks. There are several studies that indicates the benefits of this measure but there are not too much studies about negative effects. In our work we tried to simulate a BitTorrent network. Once we have this network ready we constructed it making clusters simulating some Traffic Localization technique. Making several simulations we want to prove how traffic localization affects users' experience