Modeling BitTorrent-like systems with many classes of users

Abstract

BitTorrent is one of the most successful peer-to-peer systems. Researchers have studied a number of aspects of the system, including its scalability, performance, efficiency and fairness. However, the complexity of the system has forced most prior analytical work to make a number of simplifying assumptions, for example, user homogeneity, or even ignore some central aspects of the protocol altogether, for example, the rate-based Tit-for-Tat (TFT) unchoking scheme, in order to keep the analysis tractable.Motivated by this, in this article we propose two analytical models that accurately predict the performance of the system while considering the central details of the BitTorrent protocol. Our first model is a steady-state one, in the sense that it is valid during periods of time where the number of users remains fixed. Freed by the complications of user time-dynamics, we account for many of the central details of the BitTorrent protocol and accurately predict a number of performance metrics. Our second model combines prior work on fluid models with our first model to capture the transient behavior as new users join or old users leave, while modelling many major aspects of BitTorrent. To the best of our knowledge, this is the first model that attempts to capture the transient behavior of many classes of heterogeneous users. Finally, we use our analytical methodology to introduce and study the performance of a flexible token-based scheme for BitTorrent, show how this scheme can be used to block freeriders and tradeoff between higher-bandwidth and lower-bandwidth users performance, and evaluate the scheme's parameters that achieve a target operational point.

Time-Critical Data Dissemination Under Flash Crowd Traffic

“…The local rarest first strategy is proposed in BitTorrent [7], and it can prevent the last block problem and increase the file availability in a BitTorrent system. The main advantage of the local rarest first strategy is to overcome the last block problem [26] by favoring rare blocks. This strategy equalizes the file block distribution to minimize the risk that some rare blocks are lost when peers owning them fail or depart the system.…”

Characterisation, design and simulation of an efficient peer-to-peer content distribution system for enterprise networks

“…Table 2 summarizes our findings with respect to P2P systems and attributes primitives; notice the focus on general P2P content distribution, and not on audio or video such as [34,35] since streaming must be treated in a different manner. From this analysis, BitTorrent [23] is selected as a suitable solution to this problem, however, we will see that in enterprise networks there are some issues that must be fixed in order to maximize connectivity and efficiency. Regarding performance, in Section 4 more information is presented with simulation experiments.…”

“…BitTorrent [23,27] is a P2P system used for content distribution; in this approach the source file is broken, sent to different hosts, then the destination has to recover it from the different sources. BitTorrent distinguishes two types of peers: seeds and downloaders.…”

Analysis and modelling of resources shared in the BitTorrent network

“…In fact, the community is nowadays still implementing modules to simulate the BitTorrent network . In the same line, there exist more theoretical works focused on modelling the network, as in the case of Liao et al . Jia et al analyse in the performance of BitTorrent communities from both the system‐level and the user‐level perspectives.…”