一种基于分层结构的动态自适应QoS分布控制模型

针对目前IP网实施QoS控制的主要难点问题，本文提出了基于分层结构的动态自适应QoS分布控制模型。本模型借鉴了DiffServ模型中基于端结点的分布控制思想，采用动态自适应的流控机制，这使得本模型不仅具有可扩展性，而且对网络的动态性与异构性具有适应能力。此外，本模型还采用分层结构将基于网络技术、视频编码技术以及FEC容错技术QoS控制策略进行有机集成，在带宽受限的情况下能为媒体流传输提供较好的服务质量。本模型已成功地应用于多媒体同步实时授课系统RealClass中。

A hierarchy model for distributed adaptive QoS control

In view of the current deficiency of QoS control in IP network, a hierarchy model for distributed adaptive QoS control is proposed. This model refers to the idea of the DiffServ model, and imports adaptive flow-control mechanism into the end-node, so the proposed model has not only good extensibility but satisfactory adaptiveness to the dynamics and heterogeneity of networks. Moreover, three QoS control strategies based on network technique, video encoding as well as Forward Error Correction (FEC) respectively, are integrated into the hierarchy model. When the bandwidth is limited, it can also provides better QoS for multimedia transmission. The model has been applied successfully in our multimedia synchronous real-time learning system named RealClass.