A Research on Internet QoS Information Sharing Environment

我们研究了一种新的机制来共享和使用应用级和网络级的服务质量（QoS）信息，用于互联网的流量管理和控制。(1)我们确认基于时间的QoS以及基于回声的QoS与镜像服务器的实际文档下载时间具有合理的相关性。在几周的时间里，我们使用timeit和echope对一组Web镜像服务器每五分钟测量一次QoS样本。QoS值是通过对每天的每个时间段和每周的每一天在每种情况下的QoS样本进行平均得到的。评估一天中同一时间段和一周中同一天的QoS值的相关性。结果表明，基于时间的QoS值比基于回波的QoS值具有更强的相关性。我们比较了几种服务器算法，发现使用QoS统计（过去几周的平均QoS值）和实时QoS pro可以提高服务器选择的性能。具体地说，一组候选服务器是根据每天和每周某一天的给定时间段的QoS统计数据选择的。然后，根据使用回声的实时QoS度量，从预选的候选服务器中选择目标服务器。(2)提出了一种新的VoIP网络QoS管理体系结构。通过使用客观的语音质量评估工具，对周期性生成的带有人工语音信号的测试呼叫进行持续、自动地监测语音质量，特别是MOS （Mean Opinion Score）。基于边缘到边缘测量的允许控制用于在各种流量条件下将双向语音流的丢包率保持在预定值以下。给出了满足目标阻塞概率和丢包率的网络设计方法。仿真用于评估基于边缘到边缘测量的网络的阻塞概率和丢包率等网络性能。实验表明，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