Results 1  10
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29
Modeling TCP latency
 in IEEE INFOCOM
, 2000
"... Abstract—Several analytic models describe the steadystate throughput of bulk transfer TCP flows as a function of round trip time and packet loss rate. These models describe flows based on the assumption that they are long enough to sustain many packet losses. However, most TCP transfers across toda ..."
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Cited by 188 (8 self)
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Abstract—Several analytic models describe the steadystate throughput of bulk transfer TCP flows as a function of round trip time and packet loss rate. These models describe flows based on the assumption that they are long enough to sustain many packet losses. However, most TCP transfers across today’s Internet are short enough to see few, if any, losses and consequently their performance is dominated by startup effects such as connection establishment and slow start. This paper extends the steadystate model proposed in [34] in order to capture these startup effects. The extended model characterizes the expected value and distribution of TCP connection establishment and data transfer latency as a function of transfer size, round trip time, and packet loss rate. Using simulations, controlled measurements of TCP transfers, and live Web measurements we show that, unlike earlier steadystate models for TCP performance, our extended model describes connection establishment and data transfer latency under a range of packet loss conditions, including no loss. I.
An Integrated Model for the Latency and SteadyState Throughput of TCP Connections
 PERFORMANCE EVALUATION
, 2000
"... While almost all of the existing models for TCP performance focus on the steadystate throughput of infinite flows, most TCP connections in today's Internet are very short and spend most of their time in the slow start phase, making steadystate models inappropriate. This paper focuses on two of the ..."
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Cited by 28 (1 self)
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While almost all of the existing models for TCP performance focus on the steadystate throughput of infinite flows, most TCP connections in today's Internet are very short and spend most of their time in the slow start phase, making steadystate models inappropriate. This paper focuses on two of the most important shortcomings of current models. Firstly, we present models for the latency of TCP Reno with independent losses for which currently no models exist. Secondly, we investigate the effects of network and protocol factors on TCP performance and quantify and isolate their contribution to TCP latency using an empirical model. Our analytic model gives a more accurate estimation of TCP latencies in Internet measurements than those predicted by [3], which extends the steady state analysis of [14] to model finite flows with correlated losses. The main features of our work are the modeling of timeouts and slow start phases which occur anywhere during the transfer and a more accurate model for the evolution of the cwnd in the slow start phase. The proposed model can also estimate the steadystate throughput of long flows. We also introduce empirical models for TCP Reno which allow a better "feel" of TCP latency and the nature of its dependence on loss probabilities and window limitation along with a sensitivity analysis of the effects of delayed acknowledgments (ACKs), window limitation and packet size on TCP latency.
TCP/IP Modeling and Validation
, 2001
"... We discuss in this article the different issues to be considered when modeling the TCP protocol in a real environment. The discussion is based on measurements we made over the Internet. We show that the Internet is so heterogeneous that a simplistic assumption about TCP congestion control or the ..."
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Cited by 18 (7 self)
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We discuss in this article the different issues to be considered when modeling the TCP protocol in a real environment. The discussion is based on measurements we made over the Internet. We show that the Internet is so heterogeneous that a simplistic assumption about TCP congestion control or the network may lead to erroneous results.
A Stochastic Model of TCP and Fair Video Transmission
, 2003
"... A stochastic model of TCP is developed. Unlike many other models, this model accounts for variations in latency and loss probability. A major strength of this model is that it easily produces the probability distribution of the congestion window. Thus, the mean as well as the median and percentiles ..."
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Cited by 16 (5 self)
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A stochastic model of TCP is developed. Unlike many other models, this model accounts for variations in latency and loss probability. A major strength of this model is that it easily produces the probability distribution of the congestion window. Thus, the mean as well as the median and percentiles can be found. It is shown that the mean congestion window can be far larger than the median. Other new insights include the effect of the rate of change of the latency on the performance of TCP. Specifically, this model predicts the wellknown TCPfriendly formula only if the roundtrip time rapidly varies. However, if the roundtrip time does not vary quickly, then the TCPfriendly formula may not hold. Both rapidly and slowly varying roundtrip times have been observed in real networks. As an application of the model, the question as to when a video can be fairly transmitted is addressed. If it is possible to transmit the video, the model yields the distribution of the size of the receiving buffer required to avoid underflow. Since the distribution can be found, it is possible to select a buffer size so that a specified percentage of users will view the video without interruption.
Stochastic Differential Equation for TCP Window Size: Analysis and Experimental Validation
 Prob. in the Engg. and Informational Sciences
"... The dominant transport protocol for the Internet is TCP (Transmission Control Protocol). The applications using this protocol range from simple email exchanges to web browsing and live audio or video streaming. Approximately 90 % of the data carried by the Internet are governed by TCP. TCP provides ..."
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Cited by 11 (2 self)
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The dominant transport protocol for the Internet is TCP (Transmission Control Protocol). The applications using this protocol range from simple email exchanges to web browsing and live audio or video streaming. Approximately 90 % of the data carried by the Internet are governed by TCP. TCP provides an endtoend (applicationtoapplication) service that ensures the
TCP is Competitive against a Limited Adversary
 SPAA, ACM Symp. of Parallelism in Algorithms and Achitectures
, 2003
"... While the wellknown Transport Control Protocol (TCP) is a de facto standard for reliable communication on the Internet, and performs well in practice, the question "how good is the TCP/IP congestion control algorithm?" is not completely resolved. In this paper, we provide some answers to this qu ..."
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Cited by 10 (4 self)
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While the wellknown Transport Control Protocol (TCP) is a de facto standard for reliable communication on the Internet, and performs well in practice, the question "how good is the TCP/IP congestion control algorithm?" is not completely resolved. In this paper, we provide some answers to this question using the competitive analysis framework. First, we prove that for networks with a single bottleneck (or point of congestion), TCP is competitive to the optimal global algorithm in minimizing the userperceived latency or flow time of the sessions. Specifically, we show that with O(1) times as much bandwidth and O(1) extra time per job, TCP is O(1)competitive against the optimal global algorithm. We observe that existing lower bounds for nonclairvoyant scheduling algorithms imply that no online, distributed, nonclairvoyant algorithm can be competitive with the optimal offline algorithm if both algorithms were given the same resources. Second, we show that TCP is fair by proving that it converges quickly to allocations where every session gets its fair share of network bandwidth.
Limit results for Markovian models of TCP
, 2001
"... We study in this paper the throughput of a TCP connection performing ideal congestion avoidance. With respect to existing studies published on the same topic, we determine upper and lower bounds for the throughput of a TCP connection experiencing an arbitrary constant loss. We then derive exact conv ..."
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Cited by 8 (1 self)
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We study in this paper the throughput of a TCP connection performing ideal congestion avoidance. With respect to existing studies published on the same topic, we determine upper and lower bounds for the throughput of a TCP connection experiencing an arbitrary constant loss. We then derive exact convergence results when the loss probability becomes arbitrarily small. A remarkable property of the results obtained in this paper is that they justify a posteriori constants, which appear in the approximation of the throughput and which has been observed earlier via simulation or experiments. The analysis is performed by assuming a finite and infinite maximum congestion window size.
TCP NewReno: SlowbutSteady or Impatient
 In Proceedings of IEEE International Conference on Communications (ICC
, 2006
"... Abstract — In this paper, we compare the throughputs of two different TCP NewReno variants, namely SlowbutSteady and Impatient. We develop analytic throughput models of these variants as a function of roundtrip time, loss event rate, and the burstiness of packet drops within a loss event. Our mod ..."
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Cited by 7 (1 self)
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Abstract — In this paper, we compare the throughputs of two different TCP NewReno variants, namely SlowbutSteady and Impatient. We develop analytic throughput models of these variants as a function of roundtrip time, loss event rate, and the burstiness of packet drops within a loss event. Our models build upon prior work on TCP Reno throughput modeling, but extend this work to provide an analytical characterization of the NewReno fast recovery algorithms. We validated our models using the ns2 simulator. Our models accurately predict the steadystate NewReno throughput for a wide range of loss rates. Based on these models, we analytically determine the preferred operating regions for each TCP variant. Our results show that the SlowbutSteady variant is comparable to or superior to the Impatient variant in all but the most extreme scenarios for network packet loss.
On the Competitiveness of AIMDTCP within a General Network Submitted to Journal Theoretical Computer
 Science Lecture Notes in Computer Science, Volume 2976/2004. LATIN, Latin American Theoretical Informatics
, 2004
"... This paper presents a new mathematical model of AIMD (Additive Increase Multiplicative Decrease) TCP for general networks that we believe is better than those previously used when it is driven by bottleneck capacities. Extending the paper by Edmonds, Datta, and Dymond that solves the single bottlene ..."
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Cited by 4 (3 self)
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This paper presents a new mathematical model of AIMD (Additive Increase Multiplicative Decrease) TCP for general networks that we believe is better than those previously used when it is driven by bottleneck capacities. Extending the paper by Edmonds, Datta, and Dymond that solves the single bottleneck case, we view AIMD as a distributed scheduling algorithm and prove that with extra resources, it is competitive against the optimal global algorithm in minimizing the average flow time of the jobs.
An Active Queue Management Scheme for Internet Congestion Control and Its Application to Differentiated Services
 In: Proceedings of IEEE ICCCN. (2000) 62–68
, 2000
"... In this paper, we propose a new active queue management algorithm, called Average Rate Early Detection (ARED). An ARED gateway measures/uses the average packet enqueue rate as a congestion indicator, and judiciously signals end hosts of incipient congestion, with the objective of reducing packet los ..."
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Cited by 3 (0 self)
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In this paper, we propose a new active queue management algorithm, called Average Rate Early Detection (ARED). An ARED gateway measures/uses the average packet enqueue rate as a congestion indicator, and judiciously signals end hosts of incipient congestion, with the objective of reducing packet loss ratio and improving link utilization. We show (via simulation in ns2) that the performance of ARED is better than RED and comparable to BLUE in terms of packet loss rate and link utilization. We also explore the use of ARED in the context of Differentiated Services architecture. We first show analytically that the widely referenced queue management mechanism, RED with in and out (RIO) cannot achieve throughput assurance and proportional bandwidth sharing. We then extend ARED and propose a new queue management mechanism, called ARED with in and out (AIO), in the assured services architecture. To share surplus bandwidth in a rateproportional manner, we incorporate into AIO the derived ana...