一个基于应用层的单源组播协议设计

由于IP组播在实现过程中遭遇了很多困难,所以应用层组播就成了Internet应用研究的热点。本文在简单地论述了应用层组播的优缺点后,提出了一个基于应用层的单源组播协议ALSSMP。此协议设计的目的是能够实现大规模直播视频。在ALSSMP中采用树拓扑优先的方法来构造组播转发树。在组播树的维护方面,利用为转发树中每一个结点预先选择一个"备用父结点"以设置预留链路思想的PCP算法。该协议既继承了应用层组播的优点,又在一定程度上克服了应用层组播的不稳定性的特点,使组播树的稳定性和可靠性大大提高。

Design of a single source application layer multicast protocol

Because of a great deal of pressure to implement IP multicast, the application layer multicast has been invigorated in Inter-net application research. After discussing the merits and demerits of application layer multicast simply, we propose an ALSSMP proto-col based on application layer in this article. The objective of ALSSMP is to implement live video on a large scale. In this research, a tree topology first approach is presented to construct multicast transmit tree. In the maintenance of multicast tree, we use the PCP algorithm which selects a backup parent node for every non-leaf node to a spare linker. This protocol, which inherits the merit of application layer multicast and overcomes the instability of application layer multicast, greatly improves the stability and reliability of multicast tree.