89 research outputs found
The risk of transmission of a viral haemorrhagic fever infection in a United Kingdom laboratory
No abstract available
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
A Result On Implicit Consensus with Application to Emissions Control
This paper is concerned with a class of decentralised
control problems that arise in contemporary applications
where agents cooperate to control and regulate a global
quantity, are limited in the manner in which they communicate
with each other, and are required to reach consensus on some
implicit variable (for instance, CO2 emissions). An algorithm
is presented for achieving this goal. A simplified application of
the algorithm to emissions control for a fleet of Plug-in Hybrid
Electric Vehicles (PHEVs) is given
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
A non-invasive method for link upgrade planning using coarse-grained measurements
A basic problem faced by network operators concerns
the provisioning of bandwidth to meet quality of service
(QoS) requirements. In the network core, the preferred solution is simply to overprovision link bandwidth. We propose a new approach to making link upgrade decisions based only on readily available coarse SNMP measurements
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
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