| 1. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
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A Taxonomy and Survey of Retransmission Based Partially Reliable Transport Protocols
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The mismatch between the services offered by the two standard transport protocols inthe Internet, TCP and UDP, and the services required by distributed multimedia applicationshas led to the development of a large number of partially reliable transportprotocols. That is, protocols which in terms of reliability places themselves betweenTCP and UDP. This paper presents a taxonomy for retransmission based, partially reliabletransport protocols, i.e., the subclass of partially reliable transport protocols thatperforms error recovery through retransmissions. The taxonomy comprises two classificationschemes: one that classifies retransmission based, partially reliable transportprotocols with respect to the reliability service they offer and one that classifies themwith respect to their error control scheme. The objective of our taxonomy is fourfold:to introduce a unified terminology; to provide a framework in which retransmissionbased, partially reliable transport protocols can be examined, compared, and contrasted;to make explicit the error control schemes used by these protocols; and, finally, to gainnew insights into these protocols and thereby suggest avenues for future research. Basedon our taxonomy, a survey was made of existing retransmission based, partially reliabletransport protocols. The survey shows how protocols are categorized according to ourtaxonomy, and exemplifies the majority of reliability services and error control schemesdetailed in our taxonomy.
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| 2. |
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| 3. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
-
A Simulation Based Performance Analysis of a TCP Extension for Best Effort Multimedia Applications
- 2002
-
Ingår i: Proceedings. - : IEEE. - 0769515525 ; , s. 327-336
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Konferensbidrag (refereegranskat)abstract
- Since TCP is considered unsuitable for the majority of the emerging multimedia applications, these applications primarily use UDP transport together with proprietary congestion control schemes that have better jitter and throughput characteristics. A common problem with these congestion control schemes is that they often exhibit a TCP-unfriendly and unfair behavior. As the number of applications that uses this kind of schemes increases, this could become a serious threat to the stability and performance of the Internet. In an attempt to make TCP a viable alternative to some best-effort multimedia applications, we have proposed an extension to TCP - PRTP-ECN. The performance of PRTP-ECN has been compared with TCP in an extensive factorial simulation experiment. This paper gives a detailed description of this simulation experiment with an emphasis on its statistical design and analysis. The analysis of the experiment includes, among other things, a series of ANOVA tests. These tests indicate that PRTP-ECN gives significant reductions in average interarrival jitter, while at the same time leads to improvements in average throughput and goodput, and better link utilization. In addition, the analysis suggests that PRTP-ECN is almost as fair as TCP and exhibits a TCP-friendly behavior
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| 4. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
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A Simulation Based Performance Evaluation of PRTP
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- PRTP is proposed to address the need of a transport service that is more suitable forapplications with soft real-time requirements, e.g., video broadcasting. It is an extensionfor partial reliability to TCP. The main idea behind PRTP is to exploit the fact thatmany soft real-time applications tolerate a limited amount of packet loss. In particular,PRTP enables an application to trade some of the reliability offered by TCP for improvedthroughput and interarrival jitter. This paper describes the design of PRTP andgives a detailed description of a simulation based performance evaluation. The performanceevaluation involved the performance of PRTP compared to TCP in long- as wellas in short-lived connections and showed that PRTP probably would give significantimprovements in performance, both in terms of throughput and interarrival jitter, for awide range of applications. The performance evaluation also suggested that PRTP is notTCP-friendly and altogether fair against competing flows and thus is not suitable for usein an environment where the main reason for packet loss is congestion, e.g., in a fixedInternet environment. We believe, however, that PRTP could be a viable alternative forwireless applications in error prone environments.
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| 5. |
- Grinnemo, Karl-Johan, 1968-
(författare)
-
A Study of Partially Reliable Transport Protocols for Soft Real-Time Applications
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The profileration of multimedia applications, such as streaming video, teleconferencing,and interactive gaming has created a tremendous challenge for the traditional transportprotocols of the Internet – UDP and TCP. Specifically, many multimedia applicationsare examples of soft real-time applications. They have often relatively stringent requirementsin terms of delay and delay jitter, but typically tolerate a limited packet loss rate.In recognition of the transport service requirements of soft real-time applications,this thesis studies the feasibility of using retransmission based, partially reliable transportprotocols for these applications. The thesis studies ways of designing retransmissionbased, partially reliable transport protocols that are congestion aware and TCP compatible.Furthermore, the transport protocols should provide a service that, in terms ofperformance metrics such as throughput, delay, and delay jitter, are suitable for soft realtimeapplications. The thesis work comprises the design, analysis, and evaluation oftwo retransmission based, partially reliable transport protocols: PRTP and PRTP-ECN.Extensive simulations have been carried out on PRTP as well as PRTP-ECN. These simulationshave in part been complemented by some theoretical analysis. The results ofthe simulations and the analysis suggest that substantial reductions in delay jitter andimprovements in throughput can indeed be obtained with both PRTP and PRTP-ECN ascompared to TCP. While PRTP reacted too slowly to congestion to be TCP-friendly andaltogether fair, PRTP-ECN was found to be both TCP-friendly and reasonably fair.The thesis work also comprises an extensive survey on retransmission based, partiallyreliable transport protocols. Based on this survey, we have proposed a taxonomyfor these protocols. The taxonomy considers two dimensions of retransmission based,partially reliable transport protocols: the transport service, and the error control scheme.
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| 6. |
- Grinnemo, Karl-Johan, 1968-
(författare)
-
A Study of Partially Reliable Transport Protocols for Soft Real-Time Applications
- 2002
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The profileration of multimedia applications, such as streaming video, teleconferencing, and interactive gaming has created a tremendous challenge for the traditional transport protocols of the Internet – UDP and TCP. Specifically, many multimedia applications are examples of soft real-time applications. They have often relatively stringent require- ments in terms of delay and delay jitter, but typically tolerate a limited packet loss rate.In recognition of the transport service requirements of soft real-time applications, this thesis studies the feasibility of using retransmission based, partially reliable trans- port protocols for these applications. The thesis studies ways of designing retransmis- sion based, partially reliable transport protocols that are congestion aware and TCP com- patible. Furthermore, the transport protocols should provide a service that, in terms of performance metrics such as throughput, delay, and delay jitter, are suitable for soft real- time applications. The thesis work comprises the design, analysis, and evaluation of two retransmission based, partially reliable transport protocols: PRTP and PRTP-ECN. Extensive simulations have been carried out on PRTP as well as PRTP-ECN. These sim- ulations have in part been complemented by some theoretical analysis. The results of the simulations and the analysis suggest that substantial reductions in delay jitter and improvements in throughput can indeed be obtained with both PRTP and PRTP-ECN as compared to TCP. While PRTP reacted too slowly to congestion to be TCP-friendly and altogether fair, PRTP-ECN was found to be both TCP-friendly and reasonably fair.The thesis work also comprises an extensive survey on retransmission based, par- tially reliable transport protocols. Based on this survey, we have proposed a taxonomy for these protocols. The taxonomy considers two dimensions of retransmission based, partially reliable transport protocols: the transport service, and the error control scheme.
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| 7. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
-
A Survey of TCP-Friendly Congestion Control Mechanisms for Multimedia Traffic
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The stability and performance of the Internet to date have in a large part been due tothe congestion control mechanism employed by TCP. However, while the TCP congestioncontrol is appropriate for traditional applications such as bulk data transfer, it hasbeen found less than ideal for multimedia applications. In particular, audio and videostreaming applications have difficulties managing the rate halving performed by TCP inresponse to congestion. To this end, the majority of multimedia applications use eithera congestion control scheme which reacts less drastic to congestion and therefore oftenis more aggressive than TCP, or, worse yet, no congestion control whatsoever. Sincethe Internet community strongly fears that a rapid deployment of multimedia applicationswhich do not behave in a fair and TCP-friendly manner could endanger the currentstability and performance of the Internet, a broad spectrum of TCP-friendly congestioncontrol schemes have been proposed. In this report, a survey over contemporary proposalsof TCP-friendly congestion control mechanisms for multimedia traffic in the Internetis presented. A classification scheme is outlined which shows how the majority of theproposed congestion control schemes emanate from a relatively small number of designprinciples. Furthermore, we illustrate how these design principles have been applied ina selection of congestion control scheme proposals and actual transport protocols.
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| 8. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
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Enhancing TCP for Applications with Soft Real-Time Constraints
- 2001
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Ingår i: Multimedia systems and applications IV. - Bellingham : SPIE. - 0819442429 ; , s. 18-31
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Konferensbidrag (refereegranskat)abstract
- Experiences in the use of the Internet as a delivery medium for multimedia-based applications have revealed serious deficiencies in its ability to provide the QoS of Multimedia Applications. We propose an extension to TCP that addresses the QoS requirements of applications with soft real-time constraints. Although, TCP has been found unsuitable for real-time applications, it can with minor modifications be adjusted to better comply with the QoS needs of applications with soft real-time requirements. Enhancing TCP with support for this group of applications is important since the congestion control mechanism of TCP assures stability of the Internet. In contrast, specialized multimedia protocols that lack appropriate congestion control can never be deployed on a large scale basis. Two factors of great importance for applications with soft real time constraints are jitter and throughput. By relaxing the reliability offered by TCP, the extension gives better jitter characteristics and an improved throughput. The extension only needs to be implemented at the receiving side. The reliability provided is controlled by the receiving application, thereby allowing a flexible tradeoff between different QoS parameters. In this paper, our TCP extension is presented and analyzed. The analysis investigates how the different application-controlled parameters influence performance. Our analysis is supported by a simulation study that investigates the tradeoff between interarrival jitter, throughput, and reliability. The simulation results also confirm that the extended version of TCP still behaves in a TCP-friendly manner
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| 9. |
- Grinnemo, Karl-Johan, 1968-, et al.
(författare)
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Evaluation of the QoS Offered by PRTP-ECN : A TCP Compliant Partially Reliable Transport Protocol
- 2001
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Ingår i: Proceedings. - London : Springer. - 9783540422174 ; , s. 217-234
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Konferensbidrag (refereegranskat)abstract
- The introduction of multimedia in the Internet imposes new QoS requirements on existing transport protocols. Since neither TCP nor UDP comply with these requirements, a common approach today is to use RTP/UDP and to relegate the QoS responsibility to the application. Even though this approach has many advantages, it also entails leaving the responsibility for congestion control to the application. Considering the importance of efficient and reliable congestion control for maintaining stability in the Internet, this approach may prove dangerous. Improved support at the transport layer is therefore needed. In this paper, a partially reliable transport protocol, PRTP-ECN, is presented. PRTP-ECN is a protocol designed to be both TCP-friendly and to better comply with the QoS requirements of applications with soft real-time constraints. This is achieved by trading reliability for better jitter characteristics and improved throughput. A simulation study of PRTP-ECN has been conducted. The outcome of this evaluation suggests that PRTPECN can give applications that tolerate a limited amount of packet loss significant reductions in interarrival jitter and improvements in throughput as compared to TCP. The simulations also verified the TCP-friendly behavior of PRTP-ECN
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| 10. |
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