摘要： 在数据传输模式中，服务器拥有比客户更强的通信传输能力的这类系统被称为不对称通信系统，如客户服务器模型与数据广播系统。这类伴随着网络、无线通信和移动计算等技术快速发展的系统都有其高效率的数据传输方式。其中广播系统包含着两种运行模式：pull-based 的客户从服务器请求数据的模式和push-based 的服务器直接将数据分发给大量客户的模式。这两种系统都需要高效的广播调度机制才能充分发挥系统的性能。分别讨论了pull-based 的按需广播和push-based 的主动广播的动态调度算法、性能参数指标及其性能特点。

关键词: 数据分发；动态调度；按需广播；主动广播；性能优化

Abstract: Asymmetric communication system, where the server has much communication capacity than clients, is emerged in modern network environment, such as the client-server model and data broadcast system, both are an efficient way to transmit data. Broadcast can be either pull-based, where clients ask for data from the server, or push-based, where the server pushes data to clients. The broadcast schedule is important to the overall system performance. This paper discusses the scheduling algorithms, performance metrics and characteristics of push-based active broadcasting and pull-based on-demand broadcasting

Key words: Data dissemination; Dynamic schedule; On-demand broadcasting; Active broadcasting; Performance optimal