A Research on Internet QoS Information Sharing Environment

我们研究了一种新的机制，共享和使用信息的应用级和网络级的服务质量（QoS）的流量管理和控制在互联网上，我们已经取得了以下成果。(1)我们确认，基于时间的QoS以及echoping为基础的QoS有一个合理的相关性，从镜像服务器的实际文件下载时间。我们在几周内每隔五分钟使用timeit和echoping对一组Web镜像服务器测量一次QoS样本。QoS值是通过在timeit和echoping的每种情况下对一天中的每个时间段和一周中的每一天的QoS样本进行平均来获得的。一天中的同一时间段和一周中的同一天的QoS值的相关性被评估。结果表明，基于时间的QoS值有更强的相关性比基于回声。我们比较了几种服务器选择算法，发现使用QoS统计（过去几周QoS值的平均值）和真实的实时QoS预测可以提高服务器选择的性能 关于我们 兵.具体地，基于一天中的给定时间段和一周中的某一天的QoS统计信息来选择一组候选服务器。然后，基于使用echoping的真实的实时QoS测量，在预先选择的候选服务器中选择目标服务器。(2)我们提出了一种新的VoIP网络的QoS管理架构。语音质量，特别是MOS（平均意见分数），是通过使用客观的语音质量评估工具，定期生成的测试呼叫携带人工语音信号，连续和自动监测。基于边缘到边缘测量的接纳控制用于在各种业务条件下将两个定向语音流的分组丢失率维持在预定值以下。给出了满足目标阻塞率和丢包率的网络设计方法。仿真被用来评估网络的性能，如阻塞概率和丢包率的网络与边缘到边缘测量为基础的准入控制。结果表明，在各种网络条件下，接纳控制都能很好地控制丢包率。少

We study a new mechanism to share and use information on application-level and network-level Quality of Service (QoS) for traffic management and control in the Internet We have obtained the following results.(1) We confirm that timeit-based QoS as well as echoping-based QoS have a reasonable correlation with actual document download time from mirror servers. We measure QoS samples every five minutes during several weeks using timeit and echoping for a set of Web mirror servers. QoS value is obtained by averaging QoS samples for each time section of the day and each day of the week in each case of timeit and echoping. Correlation in QoS values of the same time section of the day and the same day of the week is evaluated. It is shown that timeit-based QoS values have stronger correlation than echoping-based ones. We compared several server algorithms and found that performance of sever selection can be improved using QoS statistics (average of past weeks QoS values) and real time QoS pro … More bing. Specifically, a set of candidate servers are selected based on QoS statistics for a given time section of the day and day of the week. A target server is, then, selected among the pre-selected candidate servers based on real time QoS measurement using echoping.(2) We propose a new QoS management architecture for VoIP networks. Voice quality, specifically MOS (Mean Opinion Score), is continuously and automatically monitored by using objective voice quality evaluation tool for periodically generated test calls carrying artificial voice signals. Edge-to-edge measurement based admission control is used to maintain packet loss ratse for both directional voice flows below a pre-determined value under various traffic conditions. Network design method is given to meet target blocking probability and packet loss rate. Simulation is used to evaluate network performance such as blocking probabilities and packet loss rates for the network with edge-to-edge measurement based admission control. It is shown that admission control works well to control packet loss rate under various network conditions. Less