The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Jon W. Mark - One of the best experts on this subject based on the ideXlab platform.
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Robust Cross-layer Design of Wireless Profiled TCP Mobile Receiver for Vertical Handover
2008Co-Authors: Humphrey Rutagemwa, Jon W. Mark, Sangheon Pack, Xuemin Shen, Student Member, Senior Member, Life FellowAbstract:Abstract—In this paper, we consider downward and upward vertical handovers in integrated wireless LAN and cellular networks, and address Wireless Profiled TCP (WP-TCP) premature Timeouts due to step increase of round-trip time and false fast retransmit due to packet reordering. Specifically, we develop a mobile receiver centric loosely coupled cross-layer design, which is easy to implement and deploy, backward compatible with the Wireless Application Protocol version 2 (WAP 2.0) architecture, and robust in the absence of perfect cross-layer information. We propose two proactive schemes called RTT Inflation and RTT Equalization. The RTT Inflation scheme suppresses premature Timeouts by carefully inflating retransmission timeout time and the RTT Equalization scheme prevents false fast retransmit by equalizing the round-trip delay experienced by all packets. We conduct extensive simulations to evaluate the performance in downward and upward vertical handovers. It is demonstrated that the proposed schemes significantly improve the performance in a wide range of network conditions. Index Terms — Cross-layer design, wireless profiled TCP, vertical handover, integrated wireless networks
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Robust Cross-Layer Design of Wireless-Profiled TCP Mobile Receiver for Vertical Handover
IEEE Transactions on Vehicular Technology, 2007Co-Authors: Humphrey Rutagemwa, Sangheon Pack, Xuemin Shen, Jon W. MarkAbstract:In this paper, we consider downward and upward vertical handovers in integrated wireless LAN and cellular networks and address wireless-profiled Transmission Control Protocol premature Timeouts due to step increase of round-trip time (RTT) and false fast retransmit due to packet reordering. Specifically, we develop a mobile-receiver centric loosely coupled cross-layer design, which is easy to implement and deploy, backward compatible with the Wireless Application Protocol version 2 architecture, and robust in the absence of perfect cross-layer information. We propose two proactive schemes, called RTT Inflation and RTT Equalization. The RTT Inflation scheme suppresses premature Timeouts by carefully inflating retransmission timeout time, and the RTT Equalization scheme prevents false fast retransmit by equalizing the round-trip delay experienced by all packets. We conduct extensive simulations to evaluate the performance in downward and upward vertical handovers. It is demonstrated that the proposed schemes significantly improve the performance in a wide range of network conditions.
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ICC - Cross-layer Design and Analysis of Wireless Profiled TCP for Vertical Handover
2007 IEEE International Conference on Communications, 2007Co-Authors: Humphrey Rutagemwa, Sangheon Pack, Xuemin Shen, Jon W. MarkAbstract:In this paper, we consider downward and upward vertical handovers in integrated wireless LAN and cellular networks, and address wireless profiled TCP premature Timeouts due to steep increase of round-trip time and false fast retransmit due to packet reordering. Specifically, we develop a mobile receiver centric loosely coupled cross-layer design, which is easy to implement and deploy, backward compatible with the wireless application protocol version 2 (WAP 2.0) architecture, and robust in the absence of cross-layer information. We propose two proactive schemes which prevent false fast retransmit by equalizing the round-trip delay experienced by all packets and suppress the premature Timeouts by carefully inflating retransmission timeout time. We conduct extensive simulations to evaluate the performance in downward and upward vertical handovers. It is demonstrated that the proposed schemes significantly improve the performance in a wide range of network conditions.
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TCP Performance and Behaviors with Local Retransmissions
The Journal of Supercomputing, 2002Co-Authors: Jon W. Mark, Sherman X. ShenAbstract:TCP has been the dominant transport protocol over the global Internet, and its performance over a hybrid wireless/wireline network has attracted much attention in recent years. This paper investigates the end-to-end TCP performance, in terms of normalized throughput, effective goodput, and packet delay, over wireless lossy links with local retransmissions. The results reveal that local retransmissions can increase the normalized TCP throughput in different wireless bandwidth, delay, and error settings, at the cost of a decrease in effective goodput and an increased packet delay. The performance observation is explained by the explored TCP endpoint behaviors, including the spurious timeout and duplicated acknowledgment. Analysis shows that spurious Timeouts with local retransmissions are rare due to the conservative TCP timeout algorithm. However, spurious duplicated acknowledgments have negative impact and a further improvement with the D-SACK proposal is evaluated.
Pasi Sarolahti - One of the best experts on this subject based on the ideXlab platform.
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forward rto recovery f rto an algorithm for detecting spurious retransmission Timeouts with tcp
RFC, 2009Co-Authors: Pasi Sarolahti, Markku Kojo, Kazunori Yamamoto, Max HataAbstract:Spurious retransmission Timeouts cause suboptimal TCP performance because they often result in unnecessary retransmission of the last window of data. This document describes the F-RTO detection algorithm for detecting spurious TCP retransmission Timeouts. F-RTO is a TCP sender-only algorithm that does not require any TCP options to operate. After retransmitting the first unacknowledged segment triggered by a timeout, the F-RTO algorithm of the TCP sender monitors the incoming acknowledgments to determine whether the timeout was spurious. It then decides whether to send new segments or retransmit unacknowledged segments. The algorithm effectively helps to avoid additional unnecessary retransmissions and thereby improves TCP performance in the case of a spurious timeout.
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forward rto recovery f rto an algorithm for detecting spurious retransmission Timeouts with tcp and the stream control transmission protocol sctp
RFC, 2005Co-Authors: Markku Kojo, Pasi SarolahtiAbstract:Spurious retransmission Timeouts cause suboptimal TCP performance because they often result in unnecessary retransmission of the last window of data. This document describes the F-RTO detection algorithm for detecting spurious TCP retransmission Timeouts. F-RTO is a TCP sender-only algorithm that does not require any TCP options to operate. After retransmitting the first unacknowledged segment triggered by a timeout, the F-RTO algorithm of the TCP sender monitors the incoming acknowledgments to determine whether the timeout was spurious. It then decides whether to send new segments or retransmit unacknowledged segments. The algorithm effectively helps to avoid additional unnecessary retransmissions and thereby improves TCP performance in the case of a spurious timeout. The F-RTO algorithm can also be applied to the Stream Control Transmission Protocol (SCTP). This memo defines an Experimental Protocol for the Internet community.
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f rto an enhanced recovery algorithm for tcp retransmission Timeouts
ACM Special Interest Group on Data Communication, 2003Co-Authors: Pasi Sarolahti, Markku Kojo, Kimmo RaatikainenAbstract:Spurious TCP retransmission Timeouts (RTOs) have been reported to be a problem on network paths involving links that are prone to sudden delays due to various reasons. Especially many wireless network technologies contain such links. Spurious retransmission Timeouts often cause unnecessary retransmission of several segments, which is harmful for TCP performance. Recent proposals for avoiding unnecessary retransmissions after a spurious RTO require use of TCP options which must be implemented and enabled at both ends of teh connection. We introduce a new TCP sender algorithm for recovery after a retransmission timeout and show that unnecessary retransmissions after a spurious retransmission timeout, improving the TCP performance considerably. The algorithm is friendly towards other TCP connections, because it follows the congestion control principles and injects packets to the network at same rate as a conventional TCP sender. We implemented the algorithm and compared its performance to conventional TCP and Eifel TCP when RTOs occurred either due to sudden delays or due to packet losses. The results show that our algorithm either improves performance or gives similar througput as the other TCP variants evaluated in different test cases.
Kimmo Raatikainen - One of the best experts on this subject based on the ideXlab platform.
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f rto an enhanced recovery algorithm for tcp retransmission Timeouts
ACM Special Interest Group on Data Communication, 2003Co-Authors: Pasi Sarolahti, Markku Kojo, Kimmo RaatikainenAbstract:Spurious TCP retransmission Timeouts (RTOs) have been reported to be a problem on network paths involving links that are prone to sudden delays due to various reasons. Especially many wireless network technologies contain such links. Spurious retransmission Timeouts often cause unnecessary retransmission of several segments, which is harmful for TCP performance. Recent proposals for avoiding unnecessary retransmissions after a spurious RTO require use of TCP options which must be implemented and enabled at both ends of teh connection. We introduce a new TCP sender algorithm for recovery after a retransmission timeout and show that unnecessary retransmissions after a spurious retransmission timeout, improving the TCP performance considerably. The algorithm is friendly towards other TCP connections, because it follows the congestion control principles and injects packets to the network at same rate as a conventional TCP sender. We implemented the algorithm and compared its performance to conventional TCP and Eifel TCP when RTOs occurred either due to sudden delays or due to packet losses. The results show that our algorithm either improves performance or gives similar througput as the other TCP variants evaluated in different test cases.
Markku Kojo - One of the best experts on this subject based on the ideXlab platform.
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forward rto recovery f rto an algorithm for detecting spurious retransmission Timeouts with tcp
RFC, 2009Co-Authors: Pasi Sarolahti, Markku Kojo, Kazunori Yamamoto, Max HataAbstract:Spurious retransmission Timeouts cause suboptimal TCP performance because they often result in unnecessary retransmission of the last window of data. This document describes the F-RTO detection algorithm for detecting spurious TCP retransmission Timeouts. F-RTO is a TCP sender-only algorithm that does not require any TCP options to operate. After retransmitting the first unacknowledged segment triggered by a timeout, the F-RTO algorithm of the TCP sender monitors the incoming acknowledgments to determine whether the timeout was spurious. It then decides whether to send new segments or retransmit unacknowledged segments. The algorithm effectively helps to avoid additional unnecessary retransmissions and thereby improves TCP performance in the case of a spurious timeout.
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forward rto recovery f rto an algorithm for detecting spurious retransmission Timeouts with tcp and the stream control transmission protocol sctp
RFC, 2005Co-Authors: Markku Kojo, Pasi SarolahtiAbstract:Spurious retransmission Timeouts cause suboptimal TCP performance because they often result in unnecessary retransmission of the last window of data. This document describes the F-RTO detection algorithm for detecting spurious TCP retransmission Timeouts. F-RTO is a TCP sender-only algorithm that does not require any TCP options to operate. After retransmitting the first unacknowledged segment triggered by a timeout, the F-RTO algorithm of the TCP sender monitors the incoming acknowledgments to determine whether the timeout was spurious. It then decides whether to send new segments or retransmit unacknowledged segments. The algorithm effectively helps to avoid additional unnecessary retransmissions and thereby improves TCP performance in the case of a spurious timeout. The F-RTO algorithm can also be applied to the Stream Control Transmission Protocol (SCTP). This memo defines an Experimental Protocol for the Internet community.
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f rto an enhanced recovery algorithm for tcp retransmission Timeouts
ACM Special Interest Group on Data Communication, 2003Co-Authors: Pasi Sarolahti, Markku Kojo, Kimmo RaatikainenAbstract:Spurious TCP retransmission Timeouts (RTOs) have been reported to be a problem on network paths involving links that are prone to sudden delays due to various reasons. Especially many wireless network technologies contain such links. Spurious retransmission Timeouts often cause unnecessary retransmission of several segments, which is harmful for TCP performance. Recent proposals for avoiding unnecessary retransmissions after a spurious RTO require use of TCP options which must be implemented and enabled at both ends of teh connection. We introduce a new TCP sender algorithm for recovery after a retransmission timeout and show that unnecessary retransmissions after a spurious retransmission timeout, improving the TCP performance considerably. The algorithm is friendly towards other TCP connections, because it follows the congestion control principles and injects packets to the network at same rate as a conventional TCP sender. We implemented the algorithm and compared its performance to conventional TCP and Eifel TCP when RTOs occurred either due to sudden delays or due to packet losses. The results show that our algorithm either improves performance or gives similar througput as the other TCP variants evaluated in different test cases.
Wuxu Peng - One of the best experts on this subject based on the ideXlab platform.
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Improving Retransmission Performance of IP-Based Transport Protocols
2015Co-Authors: Stan Mcclellan, Wuxu PengAbstract:Abstract—This paper analyzes the algorithm used for es-timating retransmission Timeouts in connection-oriented IP-based transport protocols, such as the Transmission Control Protocol (TCP) and the Stream Control Transmission Protocol (SCTP). The estimation algorithm uses historical values of the round-trip time to estimate future round-trip delays, and so creates a maximum waiting time before triggering retransmission attempts. The purpose of the analysis is to question / validate some of the fundamental assumptions used in the estimation algorithm. The conclusion of the analysis is that the algorithm is somewhat mismatched to the dynamics of the current Internet. Alternative algorithms are discussed, and potential modifications are presented. Impact of the suggested alternative algorithm on the well-known selective acknowledge-ment and fast retransmit mechanisms is discussed. Keywords-SCTP; retransmission timeout; round-trip time; RTT; RTO; selective acknowledgment; fast retransmits; Ja-cobson algorithm; Chebyshev approximation; parameter esti-mation; upper bound. I
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RTOmin as a balancing parameter between fast retransmissions and Timeouts within stream control transmission protocol (SCTP)
The 2014 2nd International Conference on Systems and Informatics (ICSAI 2014), 2014Co-Authors: Eduardo González, Stan Mcclellan, Wuxu PengAbstract:The Stream Control Transmission Protocol (SCTP) is a transport layer protocol introduced to complement the well known User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP). The current implementation of SCTP heavily leverages some existing mature techniques from TCP. This paper studies the effect that RTOmin (retransmission timeout minimum) has on the selective acknowledgement (SACK), fast retransmission, and timeout mechanisms. We show that there are optimization opportunities in the manipulation of RTOmin while not significantly affecting timeout values and number of fast retransmissions. We demonstrate that RTOmin plays a balancing role in the trigger of Timeouts and fast retransmissions and conclude that a dynamically set RTOmin would yield significant time-to-complete (throughput) improvements for SCTP based applications.
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ICSAI - RTOmin as a balancing parameter between fast retransmissions and Timeouts within stream control transmission protocol (SCTP)
The 2014 2nd International Conference on Systems and Informatics (ICSAI 2014), 2014Co-Authors: Eduardo González, Stan Mcclellan, Wuxu PengAbstract:The Stream Control Transmission Protocol (SCTP) is a transport layer protocol introduced to complement the well known User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP). The current implementation of SCTP heavily leverages some existing mature techniques from TCP. This paper studies the effect that RTOmin (retransmission timeout minimum) has on the selective acknowledgement (SACK), fast retransmission, and timeout mechanisms. We show that there are optimization opportunities in the manipulation of RTOmin while not significantly affecting timeout values and number of fast retransmissions. We demonstrate that RTOmin plays a balancing role in the trigger of Timeouts and fast retransmissions and conclude that a dynamically set RTOmin would yield significant time-to-complete (throughput) improvements for SCTP based applications.
