Issues in the design of switched linear systems : a benchmark study

In this paper we present a tutorial overview of some of the issues that arise in the design of switched linear control systems. Particular emphasis is given to issues relating to stability and control system realisation. A benchmark regulation problem is then presented. This problem is most naturally solved by means of a switched control design. The challenge to the community is to design a control system that meets the required performance specifications and permits the application of rigorous analysis techniques. A simple design solution is presented and the limitations of currently available analysis techniques are illustrated with reference to this example

Positive matrices associated with synchronised communication networks

AbstractWe study the spectrum of a positive matrix that arises in the study of certain communication networks. Bounds are given on the rate of convergence of the networks to the equilibrium condition

Next generation TCP: open questions.

While there has been significant progress in recent years in the development of TCP congestion control algorithms for high BDP paths, consensus remains lacking with regard to a number of basic issues. The aim of the present paper is to highlight some of these key bottleneck issues and present a number of new results with a view to promoting discussion and fostering progress. Issues highlighted include: impact of shape of cwnd evolution (concave, convex etc), increased variability in throughputs in unsynchronised environments when more aggressive algorithms are used, impact of proposed changes on convergence rates and network responsiveness and the associated impact on user experience

Impact of Drop Synchronisation on TCP Fairness in High Bandwidth-Delay Product Networks.

In this paper we consider the performance of several well known high speed protocols in environments where individual flows experience different probabilities of seeing a drop in drop-tail buffers. Our initial results suggest the properties of networks in which these protocols are deployed can be sensitive to changes in these probabilities. Our results also suggest that AQM protocol co-design may be helpful in mitigating this sensitivity

Partitioning and Invariance of AIMD Dynamics in Synchronised Networks.

In this paper we present new results on the dynamics of networks of AIMD flows. The results reveal an invariance and partitioning property that indicates potential for the design of soundly-based adaptive AIMD strategies

Experimental evaluation of Cubic-TCP

In this paper we present an initial experimental evaluation of the recently proposed Cubic-TCP algorithm. Results are presented using a suite of benchmark tests that have been recently proposed in the literature [12], and a number of issues are of practical concern highlighted

Experimental evaluation of Cubic-TCP

In this paper we present an initial experimental evaluation of the recently proposed Cubic-TCP algorithm. Results are presented using a suite of benchmark tests that have been recently proposed in the literature [12], and a number of issues are of practical concern highlighted

Modelling TCP congestion control dynamics in drop-tail environments

In this paper we study communication networks that employ drop-tail queueing and additive-increase multiplicative-decrease (AIMD) congestion control algorithms. We show that the theory of non-negative matrices may be employed to model such networks and to derive basic theorems concerning their behaviour

Experimental Evaluation of delay/loss-based TCP congestion control algorithms.

We present initial experimental results for TCP Illinois and Compound TCP. These tests are for relatively simple scenarios yet they are sufficient to highlight several interesting issues. We observe that both TCP Illinois and Compound TCP can exhibit poor scaling behaviour as path BDP increases. As a result, link utilisation can be low and network responsiveness can become sluggish as BDP increases. We also document a number of important implementation issues observed during our tests