Download or read book Combined Queue Rate Active Queue Management for Internet Congestion Control written by Ramin Nikaeen and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The 'Combined Queue-Rate Active Queue Management' (' QR-AQM') algorithm randomly drops the arriving packets, before the buffer overflows, to effectively control the: (1) 'Actual Queue Size' below a 'Desired Optimum Queue Size' (' Qopt') to limit queueing delay and avoid buffer overflows; (2) 'Buffer's Average Traffic Arrival Rate' in the vicinity of the 'Outgoing Link Capacity' to enable the control of congestion and queue size. QR-AQM combines the 'Actual Queue Size' and queue's 'Average Traffic Arrival Rate', in computing the ' Packet Drop Probability' upon each packet's arrival, by comparing the 'Expected' and 'Desired'/'Allowed ' changes in the queue level over a tunable 'Control Time Constant ' ('Tm') period, to achieve a better performance compared to schemes that use only the 'Average Queue Size' such as ' Random Early Detection' ('RED'). The performance comparisons of 'Linear' and 'Quadratic' QR-AQM to RED reveal that QR-AQM achieves its intended goals with a superior performance.

Download or read book Combined Queue Rate Active Queue Management for Internet Congestion Control written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving Internet Congestion Control and Queue Management Algorithms written by Wu-Chang Feng and published by . This book was released on 1999 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Modelling and Evaluation of Active Queue Management Techniques in Communication Networks written by Hussein F. Abdel-Jaber and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the field of computer networks has rapidly grown in the last two decades, congestion control of traffic loads within networks has become a high priority. Congestion occurs in network routers when the number of incoming packets exceeds the available network resources, such as buffer space and bandwidth allocation. This may result in a poor network performance with reference to average packet queueing delay, packet loss rate and throughput. To enhance the performance when the network becomes congested, several different active queue management (AQM) methods have been proposed and some of these are discussed in this thesis. Specifically, these AQM methods are surveyed in detail and their strengths and limitations are highlighted. A comparison is conducted between five known AQM methods, Random Early Detection (RED), Gentle Random Early Detection (GRED), Adaptive Random Early Detection (ARED), Dynamic Random Early Drop (DRED) and BLUE, based on several performance measures, including mean queue length, throughput, average queueing delay, overflow packet loss probability, packet dropping probability and the total of overflow loss and dropping probabilities for packets, with the aim of identifying which AQM method gives the most satisfactory results of the performance measures. This thesis presents a new AQM approach based on the RED algorithm that determines and controls the congested router buffers in an early stage. This approach is called Dynamic RED (REDD), which stabilises the average queue length between minimum and maximum threshold positions at a certain level called the target level to prevent building up the queues in the router buffers. A comparison is made between the proposed REDD, RED and ARED approaches regarding the above performance measures. Moreover, three methods based on RED and fuzzy logic are proposed to control the congested router buffers incipiently. These methods are named REDD1, REDD2, and REDD3 and their performances are also compared with RED using the above performance measures to identify which method achieves the most satisfactory results. Furthermore, a set of discrete-time queue analytical models are developed based on the following approaches: RED, GRED, DRED and BLUE, to detect the congestion at router buffers in an early stage. The proposed analytical models use the instantaneous queue length as a congestion measure to capture short term changes in the input and prevent packet loss due to overflow. The proposed analytical models are experimentally compared with their corresponding AQM simulations with reference to the above performance measures to identify which approach gives the most satisfactory results. The simulations for RED, GRED, ARED, DRED, BLUE, REDD, REDD1, REDD2 and REDD3 are run ten times, each time with a change of seed and the results of each run are used to obtain mean values, variance, standard deviation and 95% confidence intervals. The performance measures are calculated based on data collected only after the system has reached a steady state. After extensive experimentation, the results show that the proposed REDD, REDD1, REDD2 and REDD3 algorithms and some of the proposed analytical models such as DRED-Alpha, RED and GRED models offer somewhat better results of mean queue length and average queueing delay than these achieved by RED and its variants when the values of packet arrival probability are greater than the value of packet departure probability, i.e. in a congestion situation. This suggests that when traffic is largely of a non bursty nature, instantaneous queue length might be a better congestion measure to use rather than the average queue length as in the more traditional models.

Download or read book Network Queue Management and Congestion Control in Internet and Wireless Networks written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Network Routing written by and published by Elsevier. This book was released on 2010-07-19 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt: Network routing can be broadly categorized into Internet routing, PSTN routing, and telecommunication transport network routing. This book systematically considers these routing paradigms, as well as their interoperability. The authors discuss how algorithms, protocols, analysis, and operational deployment impact these approaches. A unique feature of the book is consideration of both macro-state and micro-state in routing; that is, how routing is accomplished at the level of networks and how routers or switches are designed to enable efficient routing. In reading this book, one will learn about 1) the evolution of network routing, 2) the role of IP and E.164 addressing in routing, 3) the impact on router and switching architectures and their design, 4) deployment of network routing protocols, 5) the role of traffic engineering in routing, and 6) lessons learned from implementation and operational experience. This book explores the strengths and weaknesses that should be considered during deployment of future routing schemes as well as actual implementation of these schemes. It allows the reader to understand how different routing strategies work and are employed and the connection between them. This is accomplished in part by the authors' use of numerous real-world examples to bring the material alive. Bridges the gap between theory and practice in network routing, including the fine points of implementation and operational experience Routing in a multitude of technologies discussed in practical detail, including, IP/MPLS, PSTN, and optical networking Routing protocols such as OSPF, IS-IS, BGP presented in detail A detailed coverage of various router and switch architectures A comprehensive discussion about algorithms on IP-lookup and packet classification Accessible to a wide audience due to its vendor-neutral approach

Download or read book An Active Queue Management for Internet Congestion and Its Application to Differentiated Service written by Ling Su and published by . This book was released on 1999 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Internet Congestion Control written by Subir Varma and published by Morgan Kaufmann. This book was released on 2015-08-18 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internet Congestion Control provides a description of some of the most important topics in the area of congestion control in computer networks, with special emphasis on the analytical modeling of congestion control algorithms. The field of congestion control has seen many notable advances in recent years and the purpose of this book, which is targeted towards the advanced and intermediate reader, is to inform about the most important developments in this area. The book should enable the reader to gain a good understanding of the application of congestion control theory to a number of application domains such as Data Center Networks, Video Streaming, High Speed Links and Broadband Wireless Networks. When seen through the lens of analytical modeling, there are a number of common threads that run through the design and analysis of congestion control protocols in all these different areas, which are emphasized in this book. The book also cuts a path through the profusion of algorithms in the literature, and puts the topic on a systematic and logical footing. Internet Congestion Control provides practicing network engineers and researchers with a comprehensive and accessible coverage of analytical models of congestion control algorithms, and gives readers everything needed to understand the latest developments and research in this area. - Examines and synthesizes the most important developments in internet congestion control from the last 20 years. - Provides detailed description on the congestion control protocols used in four key areas; broadband wireless networks, high speed networks with large latencies, video transmission networks, and data center networks. - Offers accessible coverage of advanced topics such as Optimization and Control Theory as applied to congestion control systems.

Download or read book Network Congestion Control written by Michael Welzl and published by John Wiley & Sons. This book was released on 2005-12-13 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the Internet becomes increasingly heterogeneous, the issue of congestion control becomes ever more important. In order to maintain good network performance, mechanisms must be provided to prevent the network from being congested for any significant period of time. Michael Welzl describes the background and concepts of Internet congestion control, in an accessible and easily comprehensible format. Throughout the book, not just the how, but the why of complex technologies including the Transmission Control Protocol (TCP) and Active Queue Management are explained. The text also gives an overview of the state-of-the-art in congestion control research and an insight into the future. Network Congestion Control: Presents comprehensive, easy-to-read documentation on the advanced topic of congestion control without heavy maths. Aims to give a thorough understanding of the evolution of Internet congestion control: how TCP works, why it works the way it does, and why some congestion control concepts failed for the Internet. Explains the Chiu/Jain vector diagrams and introduces a new method of using these diagrams for analysis, teaching & design. Elaborates on how the theory of congestion control impacts on the practicalities of service delivery. Includes an appendix with examples/problems to assist learning. Provides an accompanying website with Java tools for teaching congestion control, as well as examples, links to code and projects/bibliography. This invaluable text will provide academics and researchers in computer science, electrical engineering and communications networking, as well as students on advanced networking and Internet courses, with a thorough understanding of the current state and future evolution of Internet congestion control. Network administrators and Internet service and applications providers will also find Network Congestion Control a comprehensive, accessible self-teach tool.

Download or read book NetBump written by George Porter and published by . This book was released on 2012 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineering large-scale data center applications built from thousands of commodity nodes requires both an underlying network that supports a wide variety of traffic demands, and low latency at microsecond timescales. Many ideas for adding innovative functionality to networks, especially active queue management strategies, require either modifying packets or performing alternative queuing to packets in-flight on the data plane. However, configuring packet queuing, marking, and dropping is challenging, since buffering in commercial switches and routers is not programmable. In this work, we present NetBump, a platform for experimenting with, evaluating, and deploying a wide variety of active queue management strategies to network data planes with minimal intrusiveness and at low latency. NetBump leaves existing switches and endhosts unmodified by acting as a ``bump on the wire, '' examining, marking, and forwarding packets at line rate in tens of microseconds to implement a variety of virtual active queuing disciplines and congestion control mechanisms. We describe the design of NetBump, and use it to implement several network functions and congestion control protocols including DCTCP and 802.1Qau quantized congestion notification.

Download or read book Mobile Computing and Sustainable Informatics written by Subarna Shakya and published by Springer Nature. This book was released on 2021-07-22 with total page 875 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers selected high-quality research papers presented at International Conference on Mobile Computing and Sustainable Informatics (ICMCSI 2021) organized by Pulchowk Campus, Institute of Engineering, Tribhuvan University, Nepal, during 29–30 January 2021. The book discusses recent developments in mobile communication technologies ranging from mobile edge computing devices, to personalized, embedded and sustainable applications. The book covers vital topics like mobile networks, computing models, algorithms, sustainable models and advanced informatics that supports the symbiosis of mobile computing and sustainable informatics.

Download or read book The Effects of Active Queue Management on Tcp Application Performance written by Long Le and published by LAP Lambert Academic Publishing. This book was released on 2009-11 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Active queue management (AQM) has been proposed by networking researchers and the Internet Engineering Task Force as a measure to preserve and improve Internet performance but has not been thoroughly evaluated under realistic conditions. This book investigates the effects of several AQM algorithms on the performance of TCP applications under realistic conditions. Our primary results are that many existing AQM algorithms do not perform as well as expected when they are used with packet dropping. However, when combined with packet marking, AQM algorithms significantly improve network and application performance over conventional drop-tail queues. Moreover, AQM enables network operators to run their networks near saturation levels with only modest increases in average response times. If packet marking is unavailable, the book presents a new form of differential treatment of flows that can be used with packet dropping and achieves a similar positive performance improvement. The book also develops a new AQM algorithm that can balance between loss rate and queuing delay to improve the overall system performance.

Download or read book Delay oriented Active Queue Management in TCP IP Networks written by Bo Yu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Internet-based applications and services are pervading everyday life. Moreover, the growing popularity of real-time, time-critical and mission-critical applications set new challenges to the Internet community. The requirement for reducing response time, and therefore latency control is increasingly emphasized. This thesis seeks to reduce queueing delay through active queue management. While mathematical studies and research simulations reveal that complex trade-off relationships exist among performance indices such as throughput, packet loss ratio and delay, etc., this thesis intends to find an improved active queue management algorithm which emphasizes delay control without trading much on other performance indices such as throughput and packet loss ratio. The thesis observes that in TCP/IP network, packet loss ratio is a major reflection of congestion severity or load. With a properly functioning active queue management algorithm, traffic load will in general push the feedback system to an equilibrium point in terms of packet loss ratio and throughput. On the other hand, queue length is a determinant factor on system delay performance while has only a slight influence on the equilibrium. This observation suggests the possibility of reducing delay while maintaining throughput and packet loss ratio relatively unchanged. The thesis also observes that queue length fluctuation is a reflection of both load changes and natural fluctuation in arriving bit rate. Monitoring queue length fluctuation alone cannot distinguish the difference and identify congestion status; and yet identifying this difference is crucial in finding out situations where average queue size and hence queueing delay can be properly controlled and reasonably reduced. However, many existing active queue management algorithms only monitor queue length, and their control policies are solely based on this measurement. In our studies, our novel finding is that the arriving bit rate distribution of all sources contains information which can be a better indication of congestion status and has a correlation with traffic burstiness. And this thesis develops a simple and scalable way to measure its two most important characteristics, namely the mean ii and the variance of the arriving rate distribution. The measuring mechanism is based on a Zombie List mechanism originally proposed and deployed in Stabilized RED to estimate the number of flows and identify misbehaving flows. This thesis modifies the original zombie list measuring mechanism, makes it capable of measuring additional variables. Based on these additional measurements, this thesis proposes a novel modification to the RED algorithm. It utilizes a robust adaptive mechanism to ensure that the system reaches proper equilibrium operating points in terms of packet loss ratio and queueing delay under various loads. Furthermore, it identifies different congestion status where traffic is less bursty and adapts RED parameters in order to reduce average queue size and hence queueing delay accordingly. Using ns-2 simulation platform, this thesis runs simulations of a single bottleneck link scenario which represents an important and popular application scenario such as home access network or SoHo. Simulation results indicate that there are complex trade-off relationships among throughput, packet loss ratio and delay; and in these relationships delay can be substantially reduced whereas trade-offs on throughput and packet loss ratio are negligible. Simulation results show that our proposed active queue management algorithm can identify circumstances where traffic is less bursty and actively reduce queueing delay with hardly noticeable sacrifice on throughput and packet loss ratio performances. In conclusion, our novel approach enables the application of adaptive techniques to more RED parameters including those affecting queue occupancy and hence queueing delay. The new modification to RED algorithm is a scalable approach and does not introduce additional protocol overhead. In general it brings the benefit of substantially reduced delay at the cost of limited processing overhead and negligible degradation in throughput and packet loss ratio. However, our new algorithm is only tested on responsive flows and a single bottleneck scenario. Its effectiveness on a combination of responsive and non-responsive flows as well as in more complicated network topology scenarios is left for future work.

Download or read book Delay oriented Active Queue Management in TCP written by Bo Yu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Internet-based applications and services are pervading everyday life. Moreover, the growing popularity of real-time, time-critical and mission-critical applications set new challenges to the Internet community. The requirement for reducing response time, and therefore latency control is increasingly emphasized. This thesis seeks to reduce queueing delay through active queue management. While mathematical studies and research simulations reveal that complex trade-off relationships exist among performance indices such as throughput, packet loss ratio and delay, etc., this thesis intends to find an improved active queue management algorithm which emphasizes delay control without trading much on other performance indices such as throughput and packet loss ratio. The thesis observes that in TCP/IP network, packet loss ratio is a major reflection of congestion severity or load. With a properly functioning active queue management algorithm, traffic load will in general push the feedback system to an equilibrium point in terms of packet loss ratio and throughput. On the other hand, queue length is a determinant factor on system delay performance while has only a slight influence on the equilibrium. This observation suggests the possibility of reducing delay while maintaining throughput and packet loss ratio relatively unchanged. The thesis also observes that queue length fluctuation is a reflection of both load changes and natural fluctuation in arriving bit rate. Monitoring queue length fluctuation alone cannot distinguish the difference and identify congestion status; and yet identifying this difference is crucial in finding out situations where average queue size and hence queueing delay can be properly controlled and reasonably reduced. However, many existing active queue management algorithms only monitor queue length, and their control policies are solely based on this measurement. In our studies, our novel finding is that the arriving bit rate distribution of all sources contains information which can be a better indication of congestion status and has a correlation with traffic burstiness. And this thesis develops a simple and scalable way to measure its two most important characteristics, namely the mean ii and the variance of the arriving rate distribution. The measuring mechanism is based on a Zombie List mechanism originally proposed and deployed in Stabilized RED to estimate the number of flows and identify misbehaving flows. This thesis modifies the original zombie list measuring mechanism, makes it capable of measuring additional variables. Based on these additional measurements, this thesis proposes a novel modification to the RED algorithm. It utilizes a robust adaptive mechanism to ensure that the system reaches proper equilibrium operating points in terms of packet loss ratio and queueing delay under various loads. Furthermore, it identifies different congestion status where traffic is less bursty and adapts RED parameters in order to reduce average queue size and hence queueing delay accordingly. Using ns-2 simulation platform, this thesis runs simulations of a single bottleneck link scenario which represents an important and popular application scenario such as home access network or SoHo. Simulation results indicate that there are complex trade-off relationships among throughput, packet loss ratio and delay; and in these relationships delay can be substantially reduced whereas trade-offs on throughput and packet loss ratio are negligible. Simulation results show that our proposed active queue management algorithm can identify circumstances where traffic is less bursty and actively reduce queueing delay with hardly noticeable sacrifice on throughput and packet loss ratio performances. In conclusion, our novel approach enables the application of adaptive techniques to more RED parameters including those affecting queue occupancy and hence queueing delay. The new modification to RED algorithm is a scalable approach and does not introduce additional protocol overhead. In general it brings the benefit of substantially reduced delay at the cost of limited processing overhead and negligible degradation in throughput and packet loss ratio. However, our new algorithm is only tested on responsive flows and a single bottleneck scenario. Its effectiveness on a combination of responsive and non-responsive flows as well as in more complicated network topology scenarios is left for future work.

Download or read book Parameter Self tuning in Internet Congestion Control written by Wu Chen and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Active Queue Management (AQM) aims to achieve high link utilization, low queuing delay and low loss rate in routers. However, it is difficult to adapt AQM parameters to constantly provide desirable transient and steady-state performance under highly dynamic network scenarios. They need to be a trade-off made between queuing delay and utilization. The queue size would become unstable when round-trip time or link capacity increases, or would be unnecessarily large when round-trip time or link capacity decreases. Effective ways of adapting AQM parameters to obtain good performance have remained a critical unsolved problem during the last fifteen years. This thesis firstly investigates existing AQM algorithms and their performance. Based on a previously developed dynamic model of TCP behaviour and a linear feedback model of TCP/RED, Auto-Parameterization RED (AP-RED) is proposed which unveils the mechanism of adapting RED parameters according to measurable networkconditions. Another algorithm of Statistical Tuning RED (ST-RED) is developed forsystematically tuning four key RED parameters to control the local stability in response to the detected change in the variance of the queue size. Under variable network scenarios like round-trip time, link capacity and traffic load, no manual parameter configuration is needed. The proposed ST-RED can adjust correspondingparameters rapidly to maintain stable performance and keep queuing delay as low as possible. Thus the sensitivity of RED?s performance to different network scenarios is removed. This Statistical Tuning algorithm can be applied to a PI controller for AQM and a Statistical Tuning PI (ST-PI) controller is also developed. The implementation of ST-RED and ST-PI is relatively straightforward. Simulation results demonstrate the feasibility of ST-RED and ST-PI and their capabilities to provide desirable transientand steady-state performance under extensively varying network conditions.

Download or read book Efficient Control of Non cooperative Traffic Using Sending Rate Estimate based Queue Management Schemes written by Venkatesh Ramaswamy and published by . This book was released on 2006 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we develop router-based queue management schemes with the ability to support quality of service (QoS) objectives in terms of bandwidth guarantees for traffic flows in the Internet. We develop simple packet dropping schemes that are inexpensively implementable at high speeds and that can achieve max-min fair bandwidth allocations to all the users. In short, we develop schemes that can approximate fair queueing using a single FIFO queue and a light-weight queue management algorithm. First, we review the state-of-the-art congestion control algorithms and argue that router-based schemes are an inescapable necessity. Router-based congestion control call be performed either by scheduling algorithms or by queue management algorithms. Scheduling algorithms employ complex per-flow queueing, and can guarantee strict QoS requirements of users. They are often considered too complex for high speed implementation and do not scale. Queue management algorithms, on the other hand, employ a FIFO queue to be shared by all flows and a simple packet dropping mechanism. This simple design makes them amenable to high speed implementations. Queue management schemes are often criticized for their lack of QoS support and their inability to protect well-behaved sources from ill-behaved sources. Second, we argue that in order to provide QoS using queue management schemes, we should make packet dropping decision a compound function of the sending rate of each flow and the instantaneous queue length, instead of just the average queue length. To pursue this idea further, we devise a novel, highly efficient algorithm that can estimate the relative sending rate of flows with a high degree of accuracy. We use this algorithm to design a family of queue management schemes called sending rate estimate based queue management (SREQM) schemes. We present different versions of SREQM optimized for memory and processing with techniques employing sampling and Bloom filters to further reduce the amount of state variables and memory required to make dropping decisions. We complement the designs with detailed simulations and analyses to show that SREQM is robust and can guarantee fairness in a wide variety of operating conditions. We also study the interaction between sources and queue management schemes using game theory, and show that SREQM can achieve Nash equilibrium, which indicates a stable operating condition. Finally, we present techniques to estimate buffer requirements with the constraint of maximizing the link utilization, and show that SREQM requires lower buffer space than other queue management schemes such as RED. We argue that high link utilization and low buffer requirements are due to the desynchronization of flows by SREQM.

Download or read book Performance Modeling of Congestion Control and Resource Allocation Under Heterogeneous Network Traffic written by Lan Wang and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: