Optimization flow control -- I: Basic algorithm and convergence

We propose an optimization approach to flow control where the objective is to maximize the aggregate source utility over their transmission rates. We view network links and sources as processors of a distributed computation system to solve the dual problem using a gradient projection algorithm. In this system, sources select transmission rates that maximize their own benefits, utility minus bandwidth cost, and network links adjust bandwidth prices to coordinate the sources' decisions. We allow feedback delays to be different, substantial, and time varying, and links and sources to update at different times and with different frequencies. We provide asynchronous distributed algorithms and prove their convergence in a static environment. We present measurements obtained from a preliminary prototype to illustrate the convergence of the algorithm in a slowly time-varying environment. We discuss its fairness property

Application-Oriented Flow Control: Fundamentals, Algorithms and Fairness

This paper is concerned with flow control and resource allocation problems in computer networks in which real-time applications may have hard quality of service (QoS) requirements. Recent optimal flow control approaches are unable to deal with these problems since QoS utility functions generally do not satisfy the strict concavity condition in real-time applications. For elastic traffic, we show that bandwidth allocations using the existing optimal flow control strategy can be quite unfair. If we consider different QoS requirements among network users, it may be undesirable to allocate bandwidth simply according to the traditional max-min fairness or proportional fairness. Instead, a network should have the ability to allocate bandwidth resources to various users, addressing their real utility requirements. For these reasons, this paper proposes a new distributed flow control algorithm for multiservice networks, where the application's utility is only assumed to be continuously increasing over the available bandwidth. In this, we show that the algorithm converges, and that at convergence, the utility achieved by each application is well balanced in a proportionally (or max-min) fair manner

Throughput and fairness of multiple TCP connections in wireless networks

TCP suffers from poor throughput performance in wireless networks. Furthermore, when multiple TCP connections compete at the base station, link errors and congestion lead to serious unfairness among the connections. Although the issue of TCP performance in wireless networks has attracted significant attention, most reports focus only on TCP throughput and assume that there is only a single connection in a congestion-free network. This paper studies the throughput and fairness of popular improvement mechanisms (the Snoop [8] and ELN [5]) and TCP variants with multiple TCP connections. Simulation results show that the improvement mechanisms under investigation are effective to improve TCP throughput in a wireless network. However, they cannot provide fairness among multiple TCP connections. From the studies presented, it is concluded that mechanisms to enhance TCP fairness are needed in wireless network

All or nothing: this is the question? The application of article 3(2) Data Protection Directive 95/46/EC to the Internet

The Data Protection Directive 95/46/EC (hereinafter the “Directive”) was passed in 1995 to harmonise the national data protection laws within the European Community with the aim of protecting the fundamental rights and freedoms of individuals including their privacy as set out under Art. 1 of the Data Protection Directive. The rules governing the processing of personal data are deemed to be inapplicable in the two instances outlined by Art.3(2). Processing of personal data taking place as part of activities falling outside of Community law are excluded from the DPD. The Directive is also deemed to be inapplicable if the processing of personal data is undertaken by a natural person in the course of a purely personal or household activity. It is the second part of Art. 3(2), which is examined in more detail. The ruling by the European Court of Justice in Lindqvist provides us with a fresh opportunity to re-examine whether the policy justifications for the exclusion under Art 3(2) continue to remain relevant in the light of widespread use of new technologies such as blogs, podcasts and web pages for processing and distributing information. Greater clarity regarding the implication of new communication technologies for DPD policy is necessary if the laws on data protection are to evolve in a coherent and principled manner