• Title, Summary, Keyword: TCP Congestion Control

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Performance Improvement of Wireless Mesh Networks using TCP Congestion Control Algorithm (TCP 혼잡제어 알고리즘을 이용한 무선 메쉬 네트워크의 성능 개선)

  • Lee, Hye-Rim;Moon, Il-Young
    • Journal of Advanced Navigation Technology
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    • v.14 no.2
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    • pp.253-259
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    • 2010
  • Wireless mesh network is flexible network like Ad hoc network or bluetooth together based on base station. But, wireless mesh network shows high packet loss and when TCP was created, however as it was design based on wired link, wireless link made more transmission error than wired link. It is existent problem of TCP congestion control algorithm that TCP unfairness and congestion collapse over wireless mesh network. When TCP operation occurs with the packet loss where is not the congestion loss, it brings the performance degradation which is serious. In this paper, in order to improve efficient TCP congestion control algorithm in wireless mesh network, we proposed that TCP can adaptively regulate the congestion window in wireless link.

A TCP-Friendly Congestion Control Scheme using Hybrid Approach for Reduction of Transmission Delay for Real-Time Video Stream (실시간 비디오 스트림의 전송지연 축소를 위한 TCP 친화적 하이브리드 혼잡제어 기법)

  • 김형진;조정현;나인호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.2
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    • pp.304-309
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    • 2004
  • Recently, the needs for multimedia stream such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic thorough the Internet, does not apply any congestion control mechanism to regulate the data flow thorough the shared network And it leads to congestion collapse of the Internet and results in long-term transmission delay. To avoid any adverse effect on the current Internet functionality, a now protocol of modification or addition of some functionality to perform congestion control and to reduce huge transmission delay in transmitting of multimedia stream are in study. TCP-friendly congestion control mechanism is classified into two : one is window-based congestion control scheme using general window management functionalities, the other is rate-based congestion control scheme using TCP modeling equation. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and late-based congestion control for multimedia stream. And we also simulate the performance of improved TEAR implementation using NS. With He simulation results, we show that the improved TEAR can provide better fairness and lower rate fluctuations than TCP.

A Study on TCP-friendly Congestion Control Scheme using Hybrid Approach for Multimedia Streaming in the Internet (인터넷에서 멀티미디어 스트리밍을 위한 하이브리드형 TCP-friendly 혼잡제어기법에 관한 연구)

  • 조정현;나인호
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.837-840
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    • 2003
  • Recently the multimedia streaming traffic such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic through the Internet, does not apply any congestion control mechanism to regulate the data flow through the shared network. If this trend is let go unchecked, these traffic will effect the performance of TCP, which is used to transport data traffic, and may lead to congestion collapse of the Internet. To avoid any adverse effort on the current Internet functionality, A study on a new protocol of modification or addition of some functionality to existing transport protocol for transmitting streaming traffic in the Internet is needed. TCP-frienly congestion control mechanism is classified with window-based congestion control scheme and rate-based congestion control scheme. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and rate-based congestion control for multimedia streaming in the internet.

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Window-based Congestion Control for Wireless TCP

  • Byun, Hee-Jung;Lim, Jong-Tae
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2405-2407
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    • 2003
  • We propose a feedback-based congestion control algorithm for the wireless TCP network. In this paper, we present a new TCP protocol to control the congestion window size. In particular, the asymptotic analysis of the wireless TCP is presented. Through simulations, our algorithm shows an improvement of TCP’s performance in wireless networks.

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Congestion Control to Improve QoS with TCP Traffic (TCP트래픽에 대한 QoS를 향상시키기 위한 폭주제어)

  • 양진영;이팔진;김종화
    • Proceedings of the IEEK Conference
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    • pp.21-24
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    • 2000
  • End-to-end congestion control mechanism have been critical to the robustness and stability of the Internet. Most of today's Internet traffic is TCP, and we expect this to remain so in the future. TCP/IP is the intermediate transport layer candidate for today's applications. TCP uses an adaptive window-based flow control. The congestion avoidance and control algorithms deployed by TCP aims at using the available network bandwidth. This paper compares different congestion control policies, and proposes the new design mechanism for future public networks

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Enhancing TCP Performance over Wireless Network with Variable Segment Size

  • Park, Keuntae;Park, Sangho;Park, Daeyeon
    • Journal of Communications and Networks
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    • v.4 no.2
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    • pp.108-117
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    • 2002
  • TCP, which was developed on the basis of wired links, supposes that packet losses are caused by network congestion. In a wireless network, however, packet losses due to data corruption occur frequently. Since TCP does not distinguish loss types, it applies its congestion control mechanism to non-congestion losses as well as congestion losses. As a result, the throughput of TCP is degraded. To solve this problem of TCP over wireless links, previous researches, such as split-connection and end-to-end schemes, tried to distinguish the loss types and applied the congestion control to only congestion losses; yet they do nothing for non-congestion losses. We propose a novel transport protocol for wireless networks. The protocol called VS-TCP (Variable Segment size Transmission Control Protocol) has a reaction mechanism for a non-congestion loss. VS-TCP varies a segment size according to a non-congestion loss rate, and therefore enhances the performance. If packet losses due to data corruption occur frequently, VS-TCP decreases a segment size in order to reduce both the retransmission overhead and packet corruption probability. If packets are rarely lost, it increases the size so as to lower the header overhead. Via simulations, we compared VS-TCP and other schemes. Our results show that the segment-size variation mechanism of VS-TCP achieves a substantial performance enhancement.

Modified TCP Congestion Control Algorithm to Improve Network Efficiency (네트워크 효율 향상을 위한 개선된 TCP 혼잡제어 알고리즘)

  • 최지현;김대영;김관웅;정경택;전병실
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.8
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    • pp.331-339
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    • 2003
  • In this paper, we propose an modified TCP congestion control algorithm using estimated RTT with congestion window parameter CWnd. Congestion window size is controlled with memorized RTT value on the congestion status. It can avoid occurrence of frequent congestion and reduce CWnd fluctuation. From simulation results, proposed algorithm shows great improvement on network efficiency and buffer utilization compared with original TCP algorithm.

A New Congestion Control Algorithm for Improving Fairness in TCP Vegas (TCP Vegas에서 공정성 향상을 위한 혼잡제어 알고리즘)

  • Lee, Sun-Hun;Song, Byung-Hoon;Chung, Kwang-Sue
    • Journal of KIISE:Information Networking
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    • v.32 no.5
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    • pp.583-592
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    • 2005
  • An important factor influencing the robustness of the Internet is the end-to-end TCP congestion control. However, the congestion control scheme of TCP Reno, the most popular TCP version on the Internet, employs passive congestion indication. It makes the network congestion worse. Brakmo and Peterson proposed a congestion control algorithm, TCP Vegas, by modifying the congestion avoidance scheme of TCP Reno. Many studies indicate that Vegas is able to achieve better throughput and higher stability than Reno. But there are three unfairness problems in Vegas. These problems hinder the spread of Vegas in the current Internet. In this paper, in order to solve these unfairness problems, we propose a new congestion control algorithm called TCP NewVegas. The proposed NewVegas is able to solve these unfairness problems effectively by using the variation of the number of queued packets in a bottleneck router. To evaluate the proposed approach, we compare the performance among NewVegas, Reno and Vegas. Through the simulation, NewVegas is shown to be able to achieve throughput and better fairness than Vegas.

Measurement of RTT for TCP Congestion Control (TCP 혼잡제어를 위한 RTT(Round trip time) 측정)

  • Kim, Eun-Gi
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.5
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    • pp.1520-1524
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    • 2000
  • TCP congestion control algorithm prevents network congestion through the control of outgoing traffic size. The network, therefore, should monitor the incoming traffic size of a TCP to determine whether or not a TCP follows standard congestion control algorithms. Some TCP friendly test algorithms are proposed, But, these algorithms cannot be used in real environments because a router in a network does not know the RTT of a TCP flow. In this study, we propose a new RTT determination algorithm that can be used in a router. Our proposed algorithms is validated through the simulation studies.

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Design of MPTCP Congestion Control based on BW measurement for Wireless Networks (무선 환경에서 MPTCP 성능 개선을 위한 대역폭 측정 기반 혼잡 제어 설계)

  • Kim, Min Sub;Lee, Jae Yong;Kim, Byung Chul
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.6
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    • pp.1127-1136
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    • 2017
  • In wireless networks, the packet loss due to the bit error is misinterpreted as loss due to the congestion state, so TCP congestion control occurs frequently and performance degradation occurs. This degradation also occurs in MPTCP(Multipath TCP), which is an extension protocol of original TCP. In MPTCP, the overall performance of the multipath is degraded. In this paper, we propose a congestion control scheme which measures the bandwidth on each path of MPTCP and reduces the congestion window size by the measured bandwidth when packet loss occurs, in order to solve the MPTCP performance degradation in the wireless environment. We also implemented the proposed congestion control in the Linux kernel and compared it with the original MPTCP in the testbed and real wireless networks. Experimental results show that the proposed congestion control has better throughput performance than original MPTCP congestion control in the wireless environment.