A Rational Approximation Method for Efficient Calculation of QoS measures in High Speed Networks

未来的宽带综合业务数字网络（b - isdn）将需要承载广泛的流量类别，从突发的可变速率源，如语音和可变速率编码视频，到平滑的恒定比特率源。此外，这些网络必须在为这些流量类提供有保证的服务质量（QoS）的同时这样做。表征这种网络性能的问题因此特别重要，因为这不仅在网络设计期间（以离线方式）必须完成，而且在联机控制目的（例如呼叫接纳控制）也必须完成。在本提案中，我们描述了一种基于使用全局有理近似（GRA）来评估网络性能的新技术，该技术具有在各种网络设置中为各种性能度量（如丢包概率）提供准确估计的潜力。我们概述了GRAs的研究，其目的是为所提出的算法提供坚实的理论基础，并开发在设计阶段和实时设置中估计网络性能的实用技术。具体来说，我们建议建立一个完整的理论基础，在此基础上开发算法，以获得各种服务质量（QoS）指标（如丢包概率和包延迟超过特定值的概率）的准确全局合理近似，并开发可用于评估大型B isdn的实用算法。

Coming Broadband Integrated Services Digital Networks (B-ISDNs) will be required to carry a broad range of traffic classes ranging from bursty, variable-rate sources, such as voice and variable-rate coded video, to smooth constant bit rate sources. Moreover, these networks will have to do so while providing a guaranteed quality-of-service (QoS) to these traffic classes. The problem of characterizing the performance of such networks is thus particularly important since this must be done, not only during the network design (in an off-line manner) but also for on-line control purposes such as call admission control. In this proposal we describe a novel technique for evaluating network performance based on the use of Global Rational Approximations (GRA) which has the potential of providing accurate estimates for a variety of performance measures such as packet loss probability in a wide variety of network settings. We outline research on GRAs whose aim is to develop a solid theoretical foundation on which the proposed algorithms can rest and to develop practical techniques for estimating network performance both during the design phase and in a real-time setting. Specifically, we propose to develop a complete theoretical foundation on which to develop algorithms for obtaining accurate global rational approximations for a variety of quality-of-service (QoS) metrics such as packet loss probability and probability that packet delay exceeds a particular value and to develop practical algorithms which can be used to evaluate large B ISDNs.