The ERICA switch algorithm for ABR traffic management in ATM networks
TL;DR: In this article, an explicit rate indication for congestion avoidance (ERICA) scheme for rate-based feedback from asynchronous transfer mode (ATM) switches is described. But the scheme is designed to achieve high link utilization with low delays and fast transient response and is also fair and robust to measurement errors caused by the variations in ABR demand and capacity.
Abstract: This paper describes the "explicit rate indication for congestion avoidance" (ERICA) scheme for rate-based feedback from asynchronous transfer mode (ATM) switches. In ERICA, the switches monitor their load on each link and determine a load factor, the available capacity, and the number of currently active virtual channels. This information is used to advise the sources about the rates at which they should transmit. The algorithm is designed to achieve high link utilization with low delays and fast transient response. It is also fair and robust to measurement errors caused by the variations in ABR demand and capacity. We present performance analysis of the scheme using both analytical arguments and simulation results. The scheme is being considered for implementation by several ATM switch manufacturers.
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TL;DR: This work transcoding of pre-encoded MPEG-1, 2 video into lower bit rates is realized through altering the coding algorithm into H.261/H.263 standards with lower spatio-temporal resolutions through heterogeneous transcoding.
Abstract: In this work, transcoding of pre-encoded MPEG-1, 2 video into lower bit rates is realized through altering the coding algorithm into H.261/H.263 standards with lower spatio-temporal resolutions. For this heterogeneous transcoding, we extract and compose a set of candidate motion vectors, from the incoming bit stream, to comply with the encoding format of the output bit stream. For the spatial resolution reduction we generate one motion vector out of a set of input motion vectors operating on the higher spatial resolution image. Finally, for the temporal resolution reduction we compose new motion vectors from the dropped frames motion vectors. Throughout the paper, we discuss the impact of motion estimation refinement on the new motion vectors and show that for all cases a simple half-pixel refinement is sufficient for near-optimum results.
359 citations
Posted Content•
TL;DR: An asynchronous distributed algorithm is presented for optimal rate calculation across the network, where optimality is understood in the maxmin sense and the algorithm quickly converges to the optimal rates and is shown to be well-behaved in transience.
Abstract: As the speed and the dynamic range of computer networks evolve, the issue of efficient traffic management becomes increasingly important. This work describes an approach to traffic management using explicit rate information provided to the source by the network. We present an asynchronous distributed algorithm for optimal rate calculation across the network, where optimality is understood in the maxmin sense. The algorithm quickly converges to the optimal rates and is shown to be well-behaved in transience.
262 citations
21 Jun 2005
TL;DR: This paper explores how a new congestion control algorithm — Rate Control Protocol (RCP) — comes much closer to emulating PS over a broad range of operating conditions, and shows that under a wide range of traffic characteristics and network conditions, RCP’s performance is very close to ideal processor sharing.
Abstract: Most congestion control algorithms try to emulate processor sharing (PS) by giving each competing flow an equal share of a bottleneck link. This approach leads to fairness, and prevents long flows from hogging resources. For example, if a set of flows with the same round trip time share a bottleneck link, TCP’s congestion control mechanism tries to achieve PS; so do most of the proposed alternatives, such as eXplicit Control Protocol (XCP). But although they emulate PS well in a static scenario when all flows are long-lived, they do not come close to PS when new flows arrive randomly and have a finite amount of data to send, as is the case in today’s Internet. Typically, flows take an order of magnitude longer to complete with TCP or XCP than with PS, suggesting large room for improvement. And so in this paper, we explore how a new congestion control algorithm — Rate Control Protocol (RCP) — comes much closer to emulating PS over a broad range of operating conditions. In RCP, a router assigns a single rate to all flows that pass through it. The router does not keep flow-state, and does no per-packet calculations. Yet we are able to show that under a wide range of traffic characteristics and network conditions, RCP’s performance is very close to ideal processor sharing.
236 citations
TL;DR: A simple, low-complexity protocol, called variable-structure congestion control protocol (VCP), that leverages only the existing two ECN bits for network congestion feedback, and yet achieves comparable performance to XCP, i.e., high utilization, negligible packet loss rate, low persistent queue length, and reasonable fairness.
Abstract: Achieving efficient and fair bandwidth allocation while minimizing packet loss and bottleneck queue in high bandwidth-delay product networks has long been a daunting challenge. Existing end-to-end congestion control (e.g., TCP) and traditional congestion notification schemes (e.g., TCP+AQM/ECN) have significant limitations in achieving this goal. While the XCP protocol addresses this challenge, it requires multiple bits to encode the congestion-related information exchanged between routers and end-hosts. Unfortunately, there is no space in the IP header for these bits, and solving this problem involves a non-trivial and time-consuming standardization process. In this paper, we design and implement a simple, low-complexity protocol, called variable-structure congestion control protocol (VCP), that leverages only the existing two ECN bits for network congestion feedback, and yet achieves comparable performance to XCP, i.e., high utilization, negligible packet loss rate, low persistent queue length, and reasonable fairness. On the downside, VCP converges significantly slower to a fair allocation than XCP. We evaluate the performance of VCP using extensive ns2 simulations over a wide range of network scenarios and find that it significantly outperforms many recently-proposed TCP variants, such as HSTCP, FAST, CUBIC, etc. To gain insight into the behavior of VCP, we analyze a simplified fluid model and prove its global stability for the case of a single bottleneck shared by synchronous flows with identical round-trip times.
204 citations
22 Aug 2005
TL;DR: A simple, low-complexity protocol, called Variable-structure congestion Control Protocol (VCP), is designed and implemented that leverages only the existing two ECN bits for network congestion feedback, and yet achieves comparable performance to XCP, ie high utilization, low persistent queue length, negligible packet loss rate, and reasonable fairness.
Abstract: Achieving efficient and fair bandwidth allocation while minimizing packet loss in high bandwidth-delay product networks has long been a daunting challenge. Existing end-to-end congestion control (eg TCP) and traditional congestion notification schemes (eg TCP+AQM/ECN) have significant limitations in achieving this goal. While the recently proposed XCP protocol addresses this challenge, XCP requires multiple bits to encode the congestion-related information exchanged between routers and end-hosts. Unfortunately, there is no space in the IP header for these bits, and solving this problem involves a non-trivial and time-consuming standardization process.In this paper, we design and implement a simple, low-complexity protocol, called Variable-structure congestion Control Protocol (VCP), that leverages only the existing two ECN bits for network congestion feedback, and yet achieves comparable performance to XCP, ie high utilization, low persistent queue length, negligible packet loss rate, and reasonable fairness. On the downside, VCP converges significantly slower to a fair allocation than XCP. We evaluate the performance of VCP using extensive ns2 simulations over a wide range of network scenarios. To gain insight into the behavior of VCP, we analyze a simple fluid model, and prove a global stability result for the case of a single bottleneck link shared by flows with identical round-trip times.
143 citations
References
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01 Jan 1991
TL;DR: The art of computer systems performance analysis by is one of the most effective vendor publications worldwide as discussed by the authors. But have you had it? Not at all? Ridiculous of you.
Abstract: the art of computer systems performance analysis by is one of the most effective vendor publications worldwide? Have you had it? Not at all? Ridiculous of you. Currently, you can get this impressive book simply here. Locate them is layout of ppt, kindle, pdf, word, txt, rar, as well as zip. Just how? Merely download and even read online in this site. Now, never ever late to read this the art of computer systems performance analysis. Whatever our proffesion, the art of computer systems performance analysis can be good source for reading. Find the existing reports of word, txt, kindle, ppt, zip, pdf, and also rar in this website. You can absolutely read online or download this book by right here. Currently, never miss it. Our goal is always to offer you an assortment of cost-free ebooks too as aid resolve your troubles. We have got a considerable collection of totally free of expense Book for people from every single stroll of life. We have got tried our finest to gather a sizable library of preferred cost-free as well as paid files. GO TO THE TECHNICAL WRITING FOR AN EXPANDED TYPE OF THIS THE ART OF COMPUTER SYSTEMS PERFORMANCE ANALYSIS, ALONG WITH A CORRECTLY FORMATTED VERSION OF THE INSTANCE MANUAL PAGE ABOVE.
2,424 citations
TL;DR: In this article, the authors present the selection criterion for selection between rate-based and credit-based approach and the key points of the debate between these two approaches are presented. And several other schemes that were considered are described.
Abstract: Congestion control mechanisms for ATM networks as selected by the ATM Forum traffic management group are described. Reasons behind these selections are explained. In particular, selection criterion for selection between rate-based and credit-based approach and the key points of the debate between these two approaches are presented. The approach that was finally selected and several other schemes that were considered are described.
520 citations
TL;DR: The authors investigate two packet-discard strategies that alleviate the effects of fragmentation and introduce early packet discard, a strategy in which the switch drops whole packets prior to buffer overflow that prevents fragmentation and restores throughput to maximal levels.
Abstract: Investigates the performance of transport control protocol (TCP) connections over ATM networks without ATM-level congestion control and compares it to the performance of TCP over packet-based networks. For simulations of congested networks, the effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. The low throughput is due to wasted bandwidth as the congested link transmits cells from "corrupted" packets, i.e., packets in which at least one cell is dropped by the switch. The authors investigate two packet-discard strategies that alleviate the effects of fragmentation. Partial packet discard, in which remaining cells are discarded after one cell has been dropped from a packet, somewhat improves throughput. They introduce early packet discard, a strategy in which the switch drops whole packets prior to buffer overflow. This mechanism prevents fragmentation and restores throughput to maximal levels. >
432 citations
TL;DR: The results show that, under appropriately selected control gains, a stable (nonoscillatory) operation of store-and-forward packet switching networks with feedback congestion control is possible.
Abstract: Addresses a rate-based feedback approach to congestion control in packet switching networks where sources adjust their transmission rate in response to feedback information from the network nodes. Specifically, a controller structure and system architecture are introduced and the analysis of the resulting closed loop system is presented. Conditions for asymptotic stability are derived. A design technique for the controller gains is developed and an illustrative example is considered. The results show that, under appropriately selected control gains, a stable (nonoscillatory) operation of store-and-forward packet switching networks with feedback congestion control is possible. >
357 citations
TL;DR: The authors formally define what it means for a system to tolerate a class of faults and obtains a simple classification of fault-tolerant systems.
Abstract: The authors formally define what it means for a system to tolerate a class of faults. The definition consists of two conditions. The first is that if a fault occurs when the system state is within the set of legal states, the resulting state is within some larger set and, if faults continue to occur, the system state remains within that larger set (closure). The second is that if faults stop occurring, the system eventually reaches a state within the legal set (convergence). The applicability of the definition for specifying and verifying the fault-tolerance properties of a variety of digital and computer systems is demonstrated. Using the definition, the authors obtain a simple classification of fault-tolerant systems. Methods for the systematic design of such systems are discussed. >
306 citations