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Unveiling the Incentives for Content Publishing in Popular BitTorrent Portals
Get PDFBitTorrent is the most popular peer-to-peer (P2P) content delivery application where individual users share various
types of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from the required resources, publishing valuable (and often copyrighted) content has serious legal implications for the users who publish the material. This raises the question that whether (at least major) content publishers behave in an altruistic fashion or have other motives such as financial incentives. In this paper, we identify the content publishers of more than 55 K torrents in two major BitTorrent portals and examine their characteristics. We discover that around 100 publishers are responsible for publishing 67% of the content, which corresponds to 75% of the downloads. Our investigation reveals several key insights about major publishers. First, antipiracy agencies and malicious users publish “fake” files to protect copyrighted content and spread malware, respectively. Second, excluding the fake publishers, ontent publishing in major BitTorrent portals appears to be largely driven by companies that try to attract consumers to
their own Web sites for financial gain. Finally, we demonstrate that profit-driven publishers attract more loyal consumers than altruistic top publishers, whereas the latter have a larger fraction of loyal consumers with a higher degree of loyalty than the former.TRUEpu
Energy reduction in small cell networks by a random on/off strategy
No full texthttp://dx.doi.org/10.1109/GLOCOMW.2013.6824982Data applications can tolerate an initial delay before packet transmission begins. It is possible to take advantage of this initial delay to reduce the energy required to operate the small access points (SAPs) and decrease transmission power in small cell networks. To demonstrate the trade-off between delay and transmit power, we consider a simple access scheme and analyze the distribution of the user equipment's (UE's) transmit distance. In the demonstration, there are a sufficient number of small cells to handle the peak traffic load. In order to reduce average power consumption, a number of SAPs are turned off during lower demands. The power consumption can be reduced further by turning all of the SAPs on and off, rather than selecting a subset and leaving them off. Since many SAPs are turned off at low traffic profile, UEs may be able to save energy by delaying their transmissions and waiting for a closer SAP to become available, thereby reducing transmission power. We analyze energy-efficiency versus delay trade-off, investigate optimality conditions for UE's transmit power and verify our analytical results via simulations. Results show that i) Instead of turning SAPs off for a long period, turning them on and off continuously and taking advantage of initial delay to connect a c yield an order of magnitude reductions in the transmit power, and ii) reduces the mean power consumption of SAP.TRUEpu
Quid Pro Quo: A Mechanism for Fair Collaboration in Networked Systems
Get PDFCollaboration may be understood as the execution of coordinated tasks (in the most general sense) by groups of users, who cooperate for achieving a common goal. Collaboration is a fundamental assumption and requirement for the correct operation of many communication systems. The main challenge when creating collaborative systems in a decentralized manner is dealing with the fact that users may behave in selfish ways, trying to obtain the benefits of the tasks but without participating in their execution. In this context, Game Theory has been instrumental to model collaborative systems and to design mechanisms for optimal allocation of tasks. In this paper, we revise the classical assumptions of these models and propose a new approach to this problem. First, we establish a system model based on heterogenous nodes (users, players), and propose a basic distributed mechanism so that, when a new task appears, it is assigned to the most suitable node. The classical technique for compensating a node that executes a task is the use of payments (which in most networks are hard or impossible to implement). Instead, we propose a distributed mechanism for the optimal allocation of tasks without payments. We prove this mechanism to be robust even in the presence of independent selfish or rationally limited players. Additionally, our model is based on weak assumptions, which makes the proposed mechanisms susceptible to be implemented in networked
systems (e.g., the Internet).pu
A Simple Approximate Analysis of Floating Content for Context-Aware Applications
Get PDFContext-awareness is a peculiar characteristic of an expanding set of applications that make use of a combination
of restricted spatio-temporal locality and mobile communications, to deliver a variety of services. Opportunistic communications satisfy well the communication requirements of these applications, because they naturally incorporate context. Recently, an opportunistic communication paradigm called "Floating Content" (FC) was proposed, to support infrastructure-less, distributed content sharing. But how good is floating content in supporting context-aware applications? In this work, we present a simple approximate analytical model for the performance analysis of context-aware applications that use
floating content. We estimate the "success probability" for a representative category of context-aware applications, and show how the system can be configured to achieve the application's target QoS. We validate our model using extensive simulations under different settings and mobility patterns, showing that our model-based predictions are highly accurate under a wide range of conditions.TRUEpu
Experimental Assessment of Benchmark-oriented Network Traffic Generators
Get PDFThe burstiness of network traffic has a profound impact on the performance on many network protocols in areas such as, congestion control (eg. TCP), multiple-access (eg.CSMA/CA), routing (eg. BGP), switching and multiplexing in general. Network measurement performance tools, have been widely used to exploit vulnerabilities, monitoring reports and
testing newly, under development protocols. Network Traffic
Generators (NTG), are capable of tracing burden from real-life traffic and replicate it offline, generating load under predefined traffic profiles such as, CBR, VBR and traffic according to well known probability distributions (Poisson process and Poissonianarrival). Though, it is not clear how accurately these tools are performing, as little study has been done. A traffic generator is required to satisfy hard real time requirements; time sensitive applications (eg. VoIP, Video), replication/emulation could lead to different than the expected experimental outcome, mainly because of the intrinsic limitations of the PC architecture and NTG’s design. Processes are competing each other for CPU attention,rising up uncertainties possibility and higher kernel overhead. The accuracy of timers , the network socket family and the policy of process scheduling should be consider as main sources of fluctuations and eventually bursty traffic generation. In this work, we use several well known statistical tools for capturing anomalies in frame generation process. Developers should take into account the rising limitations for better NTG design and implementation.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Interval scheduling to maximize bandwidth provision
Get PDFWe study an interval scheduling problem in which each job j is associated with a time interval Ij, a minimum aj and maximum bj required bandwidths, and a weight wj. We are given W colors. We need to assign to each job j between aj and bj colors, such that each color is assigned at each time to at most one interval. The weighted bandwidth allocated to job j is the number of colors allocated to it times |Ij|, and the weighted bandwidth of a coloring is the sum of the weighted bandwidth of all jobs. The objective is to find a coloring with maximum weighted bandwidth. A coloring is (circularly) contiguous if the set of colors for each job forms an (circular) interval.TRUEpu
Control Theoretic Optimization of 802.11 WLANs: Implementation and Experimental Evaluation
Get PDFIn 802.11 WLANs, adapting the contention parameters to network conditions results in substantial performance improvements. Even though the ability to change these parameters has been available in standard devices for years, so far no adaptive mechanism using this functionality has been validated in a realistic deployment. In this paper we report our experiences with implementing and evaluating two adaptive algorithms based on control theory, one centralized and one distributed, in a large-scale testbed consisting of 18 commercial off-the-shelf devices. We conduct extensive measurements, considering different network conditions in terms of number of active nodes, link qualities and traffic generated. We show that both algorithms significantly outperform the standard configuration in terms of total throughput. We also identify the limitations inherent in distributed schemes, and demonstrate that the centralized approach substantially improves performance under a large variety of scenarios, which confirms its suitability for real deployments.TRUEpu
