tailieunhanh - File-sharing in the Internet: A characterization of P2P traffic in the backbone

Since the outbreak of peer-to-peer (P2P) networking with Napster during the late ’90s, P2P applications have multiplied, become sophisticated and emerged as a significant fraction of Internet traffic. At first, P2P traffic was easily recognizable since P2P protocols used specific application TCP or UDP port numbers. However, current P2P applications have the ability to use arbitrary ports to “camouflage” their existence. Thus only a portion of P2P traffic is clearly identifiable. As a result, estimates and statistics regarding P2P traffic are unreliable. In this paper we present a characterization of P2P traffic in the Internet. We develop several heuristics that allow us to recognize P2P traffic at nonstandard ports. We find that. | File-sharing in the Internet A characterization of P2P traffic in the backbone. Thomas Karagiannis Andre Broido Nevil Brownlee k claffy Michalis Faloutsos UC Riverside CAIDA SDSC UCSD UC Riverside Abstract Since the outbreak of peer-to-peer P2P networking with Napster during the late 90s P2P applications have multiplied become sophisticated and emerged as a significant fraction of Internet traffic. At first P2P traffic was easily recognizable since P2P protocols used specific application TCP or UDP port numbers. However current P2P applications have the ability to use arbitrary ports to camouflage their existence. Thus only a portion of P2P traffic is clearly identifiable. As a result estimates and statistics regarding P2P traffic are unreliable. In this paper we present a characterization of P2P traffic in the Internet. We develop several heuristics that allow us to recognize P2P traffic at nonstandard ports. We find that depending on the protocol and metric used approximately 30 -70 of traffic related to P2P applications cannot be identified using well-known ports. In addition we present several characteristics for various P2P networks such as eDonkey2000 Fasttrack Gnutella BitTorrent Napster and Direct Connect as seen in traffic samples from two Tier1 commercial backbones in 2002 and 2003. I. Introduction Over the last two years peer-to-peer P2P activity has been a significant and growing component of Internet traffic. P2P applications are among the most popular applications the top 5 downloads at SourceForge 39 4 August 2003 were P2P applications. However documentation of characteristics of P2P traffic has been limited. P2P networking refers to virtual networks of computers that replace the distinct notions of server and client nodes with the the notion of peers. Despite huge differences among peers with respect to processing connection speed local network configuration or operating system each member of the P2P network has the same functionality at the .