AFStart: An adaptive fast TCP slow start for wide area networks
Nirwan Ansari2012, 2012 IEEE International Conference on Communications (ICC)
Sign up for access to the world's latest research
checkGet notified about relevant papers
checkSave papers to use in your research
checkJoin the discussion with peers
checkTrack your impact
Abstract
Transmission Control Protocol (TCP) slow start degrades TCP performance under conditions of long-distance and high end-to-end latency, i.e., inherent characteristics of wide area networks (WANs). In this paper, we propose a new TCP slow start algorithm for WANs, called Adaptive Fast Start (AFStart), which incorporates an inline available bandwidth measurement over TCP technique into TCP slow start to set the slow start threshold adaptively and adjusts the congestion window intelligently. The performance of AFStart is evaluated through simulations using the dumb-bell topology and parking-lot topology by applying AFStart to Fast TCP. The simulation results show that AFStart can ramp up the congestion window from its initial value to the slow start threshold more quickly and smoothly than standard slow start, and AFStart achieves higher network link utilization and TCP throughput during the slow start than Fast TCP.
Related papers
CapStart: An Adaptive TCP Slow Start for High Speed Networks
2009 First International Conference on Evolving Internet, 2009
In this document, we introduce Cap Start TCP, an adaptive Slow Start scheme that consistently achieves fast TCP file transfer times regardless of high speed network scenario. Once the TCP session is established, we estimate TCP session path capacity scenario, and tune the transport protocol to deliver fast transfer times. We demonstrate significant transaction performance improvements, of as much as three times faster completion times in transcontinental high speed network experiments for various capacity scenarios.
TCP Window Based Congestion Control -Slow-Start Approach
Communications and Network, 2011
Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tends to reduce speed in the face of congestion thereby penalizing itself. In this group are the window based congestion control algorithms that use the size of congestion window to determine transmission speed. The two main algorithm of window based congestion control are the congestion avoidance and the slow start. The aim of this study is to survey the various modifications of window based congestion control. Much work has been done on congestion avoidance hence specific attention is placed on the slow start in order to motivate a new direction of research in network utility maximization. Mathematical modeling of the internet is discussed and proposals to improve TCP startup were reviewed. There are three lines of research on the improvement of slow start. A group uses the estimation of certain parameters to determine initial speed. The second group uses bandwidth estimation while the last group uses explicit request for network assistance to determine initial startup speed. The problems of each proposal are analyzed and a multiple startup for TCP is proposed. Multiple startups for TCP specify that startup speed is selectable from an n-arry set of algorithms. We then introduced the e-speed start which uses the prevailing network condition to determine a suitable starting speed.
Enhanced Congestion Control Algorithm for High-Speed TCP
Lecture Notes in Computer Science, 2005
Current TCP congestion control can be inefficient and unstable in high-speed wide area networks due to its slow response with a large congestion window. Several congestion control proposals have already been suggested to solve these problems. In this paper, we propose a new variant of TCP for a high-speed network, which combines delay-based congestion control with loss-based congestion control. Our simulation results show that the proposed scheme performs better than the existing high-speed TCP protocols in terms of fairness, stability, and scalability, while providing TCP friendliness at the same time.
Restricted Slow-Start for TCP
2005 IEEE International Conference on Cluster Computing, 2005
In network protocol research a common goal is optimal bandwidth utilization, while still being network friendly. The drawback of TCP in networks with large bandwidth-delay products due to its AIMD based congestion control mechanism is well known. The congestion control algorithm of TCP has two phases namely slow-start phase and congestion-avoidance phase. Many researchers have focused on modifying the congestion avoidance phase of the algorithm. In this work, we propose a modification to the slow-start phase of the algorithm to achieve better performance. Restricted slow-start algorithm is a simple sender side alteration to the TCP congestion window update algorithm.
Performance Analysis of TCP Congestion Control Algorithms
The demand for fast transfer of large volumes of data, and the deployment of the network infrastructures is ever increasing. However, the dominant transport protocol of today, TCP, does not meet this demand because it favors reliability over timeliness and fails to fully utilize the network capacity due to limitations of its conservative congestion control algorithm. The slow response of TCP in fast long distance networks leaves sizeable unused bandwidth in such networks. A large variety of TCP variants have been proposed to improve the connection's throughput by adopting more aggressive congestion control algorithms. Some of the flavors of TCP congestion control are loss-based, high-speed TCP congestion control algorithms that uses packet losses as an indication of congestion; delay-based TCP congestion control that emphasizes packet delay rather than packet loss as a signal to determine the rate at which to send packets. Some efforts combine the features of loss-based and delay-based algorithms to achieve fair bandwidth allocation and fairness among flows. A comparative analysis between different flavors of TCP congestion control namely Standard TCP congestion control (TCP Reno), loss-based TCP congestion control (HighSpeed TCP, Scalable TCP, CUBIC TCP), delay-based TCP congestion control (TCP Vegas) and mixed loss-delay based TCP congestion control (Compound TCP) is presented here in terns of congestion window verses elapsed time after the connection is established.
Comparative performance analysis of TCP-based congestion control algorithms
International Journal of Communication Networks and Distributed Systems, 2016
In order to curtail the escalating packet loss rates caused by an exponential increase in network traffic, active queue management techniques such as Random Early Detection (RED) have come into picture. Flow Random Early Drop (FRED) keeps state based on instantaneous queue occupancy of a given flow. FRED protects fragile flows by deterministically accepting flows from low bandwidth connections and fixes several shortcomings of RED by computing queue length during both arrival and departure of the packet. Stochastic Fair Queuing (SFQ) ensures fair access to network resources and prevents a busty flow from consuming more than its fair share. In case of (Random Exponential Marking) REM, the key idea is to decouple congestion measure from performance measure (loss, queue length or delay). Stabilized RED (SRED) is another approach of detecting nonresponsive flows. In this paper, we have shown a comparative analysis of throughput, delay and queue length for the various congestion control algorithms RED, SFQ and REM. We also included the comparative analysis of loss rate having different bandwidth for these algorithms.
Analysis of TCP Congestion Control Queuing Mechanism and Investigation for High Throughput and Low Queuing Delay
2020
A protocol is a set of rules that governs data communication which decides when to communicate, how to communicate and where to communicate and also what to communicate. One of them is Transmission Control Protocol (TCP) that is the most popular and known protocol for controlling of the data transmission from source to destination or from one node to another node. It gives the best results in offline streaming of the data as compared to User Datagram Protocol (UDP). Congestion is the mechanism in networking that takes place in the time of communication when the data exceeds from its actual limit and it becomes overhead then congestion problem occurs. It usually occurs on the network like if there exist a router then the overhead occurs on router when there is limited time-baud buffer due to which the data may loss or overhead occurs. For this solution TCP is the best option to control and avoid from this problem. In this paper, an analysis has been made with the help of TCP for examining the congestion control queuing mechanism. Along with that, some parameters have been taken into account take are throughput and delay. These parameters have been tested under different settings and have been showed that by utilizing TCP congestion control queuing approach high throughput and low delay of queuing has encountered. From OPNET simulation results it has been concluded that TCP have shown remarkable and outstanding performance for controlling congestion issue with the help of other existing schemes that has shown poor performance.
Fair TCP: A Novel TCP Congestion Control Algorithm to Tackle TCP's Challenges
asiafi.net
The Transport Control Protocol (TCP) has contributed to the tremendous success of the Internet but it also includes many problems which are becoming more and more significant as the network grows. Although numerous congestion algorithms have been proposed to improve the performance of TCP in heterogeneous networks, designing a congestion algorithm that could achieve high utilization, ensure fairness and maintain stability remains a great challenge. In this paper, we propose a novel congestion control algorithm named FTCP to tackle these challenges. FTCP is trying to solve TCP's challenges by adjusting its initial congestion window (cwnd) and cwnd updating rate with the aids of measuring the bottleneck queue length. To evaluate the performance of our algorithm, extensive experiments have been performed using network simulation tool. Experimental results prove that FTCP has obvious advantages in efficiency, fairness, TCP friendliness and stability comparing to the existing stateof-the-art congestion control algorithms.
Enhanced TCP Westwood Slow Start Phase
Transactions on Networks and Communications, 2014
Many end-to-end TCP implementations have been presented in the past decade. Despite that they used different methods to improve transport protocols over wireless networks; they mostly shared the same original TCP principles. TCP Westwood introduced a novel end-to-end bandwidth estimation mechanism. Nevertheless, it maintains the same slow start phase presented in TCP Reno. For the initial slow start phase, there is no safe slow start threshold value. In this paper, we propose to use the bandwidth estimation to calculate the initial slow start threshold value after the second round trip time. Furthermore, we introduce a faster state in which TCP increases the transmission rate once the link is underutilizing. As a result, the new proposed method shows better performance comparing to TCP Westwood, and TCP NewReno techniques.
A Sender-Side TCP Enhancement for Startup Performance in High-Speed Long-Delay Networks
Many previous studies have shown that traditional TCP slow-start algorithm suffers performance degradation in high-speed and long-delay networks. This paper presents a sender-side enhancement, which makes use of TCP Vegas congestion-detecting scheme to monitor the router queue, and accordingly refines slow-start window evolution by introducing a two-phase approach to probe bandwidth more efficiently. Moreover, it achieves good fairness of bandwidth utilization in coexistence of multiple connections. Simulation results show that, compared with traditional slow-start and many other enhancements, it is able to significantly improve the startup performance without adversely affecting coexisting TCP connections.
Related topics
Related papers
Improving TCP Start-Up Behavior In High-Speed Networks
Workshop on High- …, 2003
Enhancing TCP Congestion Control Via Connection Bandwidth Estimation, A Performance Study
We present performance studies of TCP Westwood (TCPW), a sender-side modification of the congestion window control scheme in TCP. TCP Westwood relies on end-to-end rate estimation. The key innovative idea is to continuously measure at the TCP sender the packet rate of the connection by monitoring the rate of returning ACKs. The estimate is then used to compute congestion window and slow start threshold after a congestion episode, that is, after three duplicate acknowledgments or a timeout. The rationale of this strategy is simple: in contrast with TCP Reno, which "blindly" halves the congestion window after three duplicate ACKs, TCP Westwood attempts to select a slow start threshold and a congestion window which are consistent with the effective connection rate at the time congestion is experienced. The proposed faster recovery mechanism is particularly effective over wireless links where sporadic losses due to radio link problems are often misinterpreted as a symptom of congestion by current TCP schemes, and thus lead to unnecessary window reduction. Experimental studies reveal improvements in throughput performance, as well as in fairness. In addition, friendliness with TCP Reno was confirmed in a set of experiments. TCP Reno connections are not starved by TCPW connections; on the contrary, the TCP Reno connections continue to make satisfactory progress. TCPW is shown here to be extremely effective in mixed wired and wireless networks and in high speed networks. Throughput improvements of up to 615 % are observed. Internet measurements using a Linux TCPW implementation are also reported in this paper, providing further evidence of the gains achievable via TCPW.
VFAST TCP: A delay-based enhanced version of FAST TCP
This paper is aimed at describing a delay-based endto-end (e2e) congestion control algorithm, called Very FAST TCP (VFAST), which is an enhanced version of FAST TCP. The main idea behind this enhancement is to smoothly estimate the Round-Trip Time (RTT) based on a nonlinear filter, which eliminates throughput and queue oscillation when RTT fluctuates. In this context, an evaluation of the suggested scheme through simulation is introduced, by comparing our VFAST prototype with FAST in terms of throughput, queue behavior, fairness, stability, RTT and adaptivity to changes in network. The achieved simulation results indicate that the suggested protocol offer better performance than FAST TCP in terms of RTT estimation and throughput.
Improving TCP Startup Performance using Active Measurements: Algorithm and Evaluation
TCP Slow Start exponentially increases the congestion window size to detect the proper congestion window for a network path. This often results in significant packet loss, while breaking off Slow Start using a limited slow start threshold may lead to an overly conservative congestion window size. This problem is especially severe in high speed networks. In this paper we present a new TCP startup algorithm, called Paced Start, that incorporates an available bandwidth probing technique into the TCP startup algorithm. Paced Start is based on the observation that when we view the TCP startup sequence as a sequence of packet trains, the difference between the data packet spacing and the acknowledgement spacing can yield valuable information about the available bandwidth. Slow Start ignores this information, while Paced Start uses it to quickly estimate the proper congestion window for the path. For most flows, Paced Start transitions into congestion avoidance mode faster than Slow Start, has a significantly lower packet loss rate, and avoids the timeout that is often associated with Slow Start. This paper describes the Paced Start algorithm and uses simulation and real system experiments to characterize its properties.
A New Scheme for TCP Congestion Control: Smooth-Start and Dynamic Recovery
Modeling, Analysis and Simulation of …, 1998
This paper presents a new approach to TCP congestion control. The new scheme includes two parts: (1) the Smooth-Start algorithm, which replaces the Slow-Start algorithm at the start of a TCP connection or after a retransmission timeout, and (2) the Dynamic Recovery algorithm, which replaces the Fast Recovery algorithm to recover packet losses when a TCP connection is congested. Both algorithms require modifications only to the sender side of the TCP implementation. Simulation is used to evaluate the performance of the algorithms. The simulation experiments are conducted using the ns simulator, to facilitate comparisons with Tahoe, Reno, New-Reno, SACK, and FACK TCP. The simulation results show that the new scheme performs at least as well as SACK and FACK TCP, which in turn consistently outperform TCP Tahoe and Reno. Furthermore, the implementation of the new scheme is simpler than that of SACK and FACK.
Experimental Evaluation of TCP Congestion Contorl Mechanisms in Short and Long Distance Networks
Originally TCP was designed for early, low bandwidth, short distance networks, so Standard TCP did not utilize the maximum bandwidth in today's high bandwidth network environments. Therefore a lot of TCP congestion control mechanisms also known as TCP variants have been developed for today's long distance high bandwidth networks. In this paper the experimental results evaluating the performance of TCP Reno, HighSpeed TCP, BIC TCP, TCP CUBIC and Compound TCP in short and long distance high bandwidth networks are presented. Results show that TCP CUBIC shows the highest performance in goodput whereas TCP Compound shows the highest performance in protocol fairness and TCP friendliness as compared to the other stat of the art congestion control mechanisms.
Enhancement of TCP congestion control based on relative delay and Bandwidth Estimation
Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology, 2012
The traditional TCP assumes that all packet losses result from the congestion even in networks with high bit error rates (BER), and this causes a significant performance degradation. In this paper, we propose a novel end-to-end congestion control mechanism called TCP VenoDB, which joins the relative delay and bandwidth estimation together as a judgment condition to distinguish the network states, and refines the traditional fast retransmit and fast recovery phase with partial ACK mechanism. Simulation results by NS-2 show that TCP VenoDB provides more significant performance improvement in throughput, bandwidth utilization and fairness than TCP Veno, TCP Westwood and TCP NewReno in networks with high BER, and has minimal influence of reverse link congestion. Furthermore, TCP VenoDB is friendly towards TCP NewReno for practical purpose.
Exploration and evaluation of traditional TCP congestion control techniques
TCP or Transmission Control Protocol represents one of the prevailing ''languages'' of the Internet Protocol Suite, complementing the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP. TCP provides reliability to data transferring in all end-to-end data stream services on the internet. This protocol is utilized by major internet applications such as the e-mail, file transfer, remote administration and world-wide-web. Other applications which do not require reliable data stream service may use the User Datagram Protocol (UDP), which provides a datagram service that emphasizes reduced latency over reliability. The task of determining the available bandwidth of TCP packets flow is in fact, very tedious and complicated. The complexity arises due to the effects of congestion control of both the network dynamics and TCP. Congestion control is an approved mechanism used to detect the optimum bandwidth in which the packets are to be sent by TCP sender. The understanding of TCP behaviour and the approaches used to enhance the performance of TCP in fact, still remain a major challenge. In conjunction to this, a considerable amount of researches has been made, in view of developing a good mechanism to raise the efficiency of TCP performance. The article analyses and investigates the congestion control technique applied by TCP, and indicates the main parameters and requirements required to design and develop a new congestion control mechanism.
Hybrid slow start for high-bandwidth and long-distance networks
2008
Slow Start is a technique to probe for unknown and time-varying available bandwidth of a network path. A sender increases its congestion window by one for each ACK received (when ACKs are not delayed), which effectively doubles its congestion window when receiving ACKs for all the packets within a congestion window. Even if an exponential increase of congestion window during Slow Start grabs unused bandwidth quite well, a large number of packet losses within an RTT is inevitable because of its overshooting. Furthermore, for fast and long distance networks, a large number of packet losses would result in unnecessarily long timeouts and create system performance bottlenecks related to handling the recovery of lost packets. We propose a new algorithm, called Hybrid Slow Start that maintains the existing Slow Start mechanism of TCP-NewReno but provides trustworthy signals to Slow Start for safely switching to Congestion Avoidance without incurring an extremely large number of packet losses. Hybrid Slow Start uses two pieces of information-ACK train length and increase in packet delays. By measuring ACK train length, a TCP sender roughly infers the maximum number of packets in flight which is typically smaller than the Bandwidth Delay Product (BDP) of the path if taken into account cross traffic and routing delays along the path. Increase in delays for the first few packets in each RTT round during Slow Start strongly indicates the path is getting congested by other traffic. Hybrid Slow Start is easy to implement using a only very small set of TCP state variables available in standard TCP. We validate our claims by applying Hybrid Slow Start to CUBIC and testing it under a realistic mix of background traffic with TCP receivers implemented in FreeBSD, Windows and Linux.
TCP Window Based Congestion Control Mechanism
Journal of Network and Information Security, 2020
As we know Transmission Control Protocol (TCP) is improving itself with the help of many researchers working in this area all over the World. Many papers and proposals have been submitted by the different researchers to improve the performance of TCP by the congestion control mechanism. In this concern paper, we are able to improve the transmission speed through the window size congestion control technique which is playing an important role in the field of communication. As we already know there are two main important techniques to overcome the congestion and these are the Avoidance algorithm and Slow start mechanism. Now to specify the TCP there are multiple start-ups are existing to specify that start-up speed is selectable from an n-array set of algorithms. If well work and implement these algorithms we can improve our performance and control the congestion. This paper provide the depth analysis of the existing congestion control techniques and provide the model which is helpful to control congestion.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.