267 research outputs found
Adaptive Active Queue Management based on Queue Ratio of Set-point Weighting
Presently, active queue management (AQM) is one of the important considerations in communication networks. The challenge is to make it simple and robust in bursty traffic and uncertain network conditions. This paper proposes a new AQM scheme, an adaptive ratio proportional integral (ARPI), for adaptively controlling network congestion in dynamic network traffic conditions. First, AQM was designed by adding a set-point weighting structure to a proportional integral (PI) controller to reduce the burstiness of network traffic. Second, an adaptive set-point weighting based on the ratio of instantaneous queue length to the set-point queue and the buffer size was proposed to improve the robustness of a non-linear network. The proposed design integrates the aforementioned expectations into one function and needs only one parameter change to adapt to fluctuating network condition. Hence, this scheme provides lightweight computation and simple software and hardware implementation. This approach was analyzed and compared with the PI AQM scheme. Evaluation results demonstrated that our proposed AQM can regulate queue length with a fast response, good stability under any traffic conditions, and small queuing delay
GA-PSO-Optimized Neural-Based Control Scheme for Adaptive Congestion Control to Improve Performance in Multimedia Applications
Active queue control aims to improve the overall communication network
throughput while providing lower delay and small packet loss rate. The basic
idea is to actively trigger packet dropping (or marking provided by explicit
congestion notification (ECN)) before buffer overflow. In this paper, two
artificial neural networks (ANN)-based control schemes are proposed for
adaptive queue control in TCP communication networks. The structure of these
controllers is optimized using genetic algorithm (GA) and the output weights of
ANNs are optimized using particle swarm optimization (PSO) algorithm. The
controllers are radial bias function (RBF)-based, but to improve the robustness
of RBF controller, an error-integral term is added to RBF equation in the
second scheme. Experimental results show that GA- PSO-optimized improved RBF
(I-RBF) model controls network congestion effectively in terms of link
utilization with a low packet loss rate and outperform Drop Tail,
proportional-integral (PI), random exponential marking (REM), and adaptive
random early detection (ARED) controllers.Comment: arXiv admin note: text overlap with arXiv:1711.0635
On Designing Lyapunov-Krasovskii Based AQM for Routers Supporting TCP Flows
For the last few years, we assist to a growing interest of designing AQM
(Active Queue Management) using control theory. In this paper, we focus on the
synthesis of an AQM based on the Lyapunov theory for time delay systems. With
the help of a recently developed Lyapunov-Krasovskii functional and using a
state space representation of a linearized fluid model of TCP, two robust AQMs
stabilizing the TCP model are constructed. Notice that our results are
constructive and the synthesis problem is reduced to a convex optimization
scheme expressed in terms of linear matrix inequalities (LMIs). Finally, an
example extracted from the literature and simulations via {\it NS simulator}
support our study
Active Queue Management via Event-Driven Feedback Control
Active queue management (AQM) is investigated to avoid incipient congestion in gateways to complement congestion control run by the transport layer protocol such as the TCP. Most existing work on AQM can be categorized as (1) ad-hoc event-driven control and (2) time-driven feedback control approaches based on control theory. Ad hoc event-driven approaches for congestion control, such as RED (random early detection), lack a mathematical model. Thus, it is hard to analyze their dynamics and tune the parameters. Time-driven control theoretic approaches based on solid mathematical models have drawbacks too. As they sample the queue length and run AQM algorithm at every fixed time interval, they may not be adaptive enough to an abrupt load surge. Further, they can be executed unnecessarily often under light loads due to the time-driven nature. To seamlessly integrate the advantages of both event-driven and control-theoretic time-driven approaches, we present an event-driven feedback control approach based on formal control theory. As our approach is based on a mathematical model, its performance is more analyzable and predictable than ad hoc event-driven approaches are. Also, it is more reactive to dynamic load changes due to its event-driven nature. Our simulation results show that our event-driven controller effectively maintains the queue length around the specified set-point. It achieves shorter E2E (end-to-end) delays and smaller E2E delay fluctuations than several existing AQM approaches, which are ad hoc event-driven and based on time-driven control theory, while achieving almost the same E2E delays and E2E delay fluctuations as the two other advanced control theoretic AQM approaches. Further, our AQM algorithm is invoked much less frequently than the tested baseline
Proportional-integral genetic algorithm controller for stability of TCP network
The life development and increase the number of internet users imposed an increase in data circulating on the internet network and then make the network more congestion. As a result of all this, some problems arose such as time delay in packets delivery, loss of packets, and exceed the buffer capacity for the middle routers. To overcome those problems, transmission control protocol and active queue management (TCP/AQM) have been used. AQM is the main approach used to control congestion and overcome those problems to improve network performance. This work proposes to use the proportional-integral (PI) controller with a genetic algorithm (GA) as an active queue manager for routers of the Internet. The simulation results show a good performance for managing the congestion with using proportional-integral genetic algorithm (GA-PI) controller better than the PI controller
Congestion Control for Streaming Media
The Internet has assumed the role of the underlying communication network for applications such as file transfer, electronic mail, Web browsing and multimedia streaming. Multimedia streaming, in particular, is growing with the growth in power and connectivity of today\u27s computers. These Internet applications have a variety of network service requirements and traffic characteristics, which presents new challenges to the single best-effort service of today\u27s Internet. TCP, the de facto Internet transport protocol, has been successful in satisfying the needs of traditional Internet applications, but fails to satisfy the increasingly popular delay sensitive multimedia applications. Streaming applications often use UDP without a proper congestion avoidance mechanisms, threatening the well-being of the Internet. This dissertation presents an IP router traffic management mechanism, referred to as Crimson, that can be seamlessly deployed in the current Internet to protect well-behaving traffic from misbehaving traffic and support Quality of Service (QoS) requirements of delay sensitive multimedia applications as well as traditional Internet applications. In addition, as a means to enhance Internet support for multimedia streaming, this dissertation report presents design and evaluation of a TCP-Friendly and streaming-friendly transport protocol called the Multimedia Transport Protocol (MTP). Through a simulation study this report shows the Crimson network efficiently handles network congestion and minimizes queuing delay while providing affordable fairness protection from misbehaving flows over a wide range of traffic conditions. In addition, our results show that MTP offers streaming performance comparable to that provided by UDP, while doing so under a TCP-Friendly rate
Switching resilient PI controllers for active queue management of TCP flows
Active Queue Management (AQM) is used in computer networks to increase link utilization with less queueing delays. The fluid flow model or TCP based on delay differential equations supplies the mathematical background for modelling the AQM as a feedback system. Recently various PI and PID controllers arr designed for this feedback system, [7], [18]. In this paper, we consider the case for which the Round Trip Time (RTT) is time varying and we propose switching resilient PI controllers using the design method introduced in [18]. © 2007 IEEE
A new PI and PID control design method and its application to active queue management of TCP flows
Cataloged from PDF version of article.PID controllers are continuing to be used in many control applications due to
their simple structures. Design of such controllers for unstable systems with time
delays is an active research area. Recently, stabilizing PI and PD controllers for
a class of unstable MIMO (multi-input multi-output) systems with input/output
delays have been investigated and allowable controller gain intervals for such
controllers have been maximized. Motivated by these studies, this thesis proposes
a new method for tuning the parameters of PI, PD and PID controllers for
integrating processes with time delays. The method is based on selecting the
centers of the maximized gain intervals as the controller gains for the purpose
of obtaining optimal controllers. As an application of this method, controllers
for AQM (Active Queue Management) of TCP (Transmission Control Protocol)
flows have been designed. AQM is a congestion control method used in computer
networks to increase link utilization with less queueing delays. The fluid flow
model of TCP’s congestion avoidance mode based on delay differential equations
supplies the mathematical background for modelling the AQM as a feedback
control system and designing different control schemes accordingly. Firstly, the
proposed controller design method has been applied to AQM for the case of
time invariant time delay and secondly the method has been supported with
switching control technique to obtain optimum system performance in the case
of time varying time delay. The performance of the designed controllers for both
cases has been illustrated by packet level simulations in ns-2.Ăśstebay, DenizM.S
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