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Traffic shaping techniques to enable applications to dynamically control their traffic loading on ATM and local area networks

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dc.contributor.author Roberts-Baxter GJ en
dc.date.accessioned 2016-09-22T11:26:45Z
dc.date.available 2016-09-22T11:26:45Z
dc.date.submitted 1996 en
dc.identifier.uri http://hdl.handle.net/20.500.11892/121892
dc.description.abstract This research presents a study into optimising performance characteristics of typical sources using the services of ATM Public networks. The main distinction between traffic types that ATM networks carry is made between delay-sensitive and delay- insensitive traffic. Broadly speaking, this can be characterised into real-time traffic such as voice and video, and data traffic such as computer information exchange. Each traffic type can be subdivided into different classes of traffic, each with their own specific characteristics and service requirements. The need for optimising the flow of traffic from different sources generating traffic which enters ATM networks thus arises. Data traffic presents a class of traffic which has vastly different characteristics as compared to time sensitive traffic, since it exhibits a unique network wasted-bandwidth/performance trade- off. Data users can tolerate longer delays in data transfer, whereas real-time traffic sources cannot, thus making the wasted-bandwidth/performance trade-off controllable for data traffic. The study presents an evaluation of two methods of optimising data traffic flow. Both traffic on local area networks, as well as traffic intended to enter ATM public networks are optimised. Optimisation has been approached and performed from two distinct viewpoints. <br><br> Firstly, optimising user performance of LANs connected to an ATM WAN, when the LANs are interconnected using SVCs. It is shown that network designers can optimise the connection process by selecting the number of users that share a SVC, and performance can be improved by holding the SVC open a time period after a transaction has been serviced. This time is called the release-time, and improves performance by reducing the number of times the SVC is set-up, since there is the probability that the next arrival will occur within the release-time. <br><br> Secondly, feedback is used to shape data traffic at the source under congestion episodes in a network. In doing so, the amount of load that the network carries which has been resent by the source is minimised. The resent load occurs when sources retransmit data that has been assumed lost due to protocol time-outs or due to frame errors resulting from congestion. By applying load control at the source, based on feedback information from the network, sources dynamically control their loads under congestion conditions. It is shown that a feedback mechanism can shorten congestion episodes and decrease peak congestion level. The algorithm expedites congestion abatement by reducing the peak congestion level, and once the congestion episode has passed, returns the system performance to normal sooner. <br><br> Through the initial phases of wide-scale ATM deployment, data traffic performance issues such as addressed in this study are likely to surface. Simulations have shown that performance can be increased through reduction of .total connection set-up time when using SVCs, and by shaping traffic at the source. The performance increases benefit both network users and improve network utilisation and efficiency for network service providers. en
dc.language English en
dc.title Traffic shaping techniques to enable applications to dynamically control their traffic loading on ATM and local area networks en
dc.type Masters degree en
dc.description.degree MSc(Eng) en

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