中文摘要：

引入了组播的概念，并对传统的IP组播作了一个简要的概述及总结归纳。然后引入应用层组播的概念，并对应用层组播的研究现状和主要的研究方法进行了详细的介绍和评述。特别是对应用层组播中所使用的几个关键技术和在该领域中所经常采用的一些算法，进行了深入的探讨和细致的总结。同时也介绍了目前在应用层组播研究领域中所遇到的几个主要问题，比如流量控制和拥塞控制，并提出了相应的解决方案。在介绍应用层组播的同时，与传统的IP层组播进行了比较，给出了两者之间存在的差别。最后，提出了一套对应用层组播算法进行评价的评估体系。

英文摘要：

The concept of multi-case is introduced, and a quick review of traditional IP layer multi-case is given. After that, a detailed introduction to ALM （application layer multicast） on 2 main points is presented： The theoretic research and its corresponding realworld implementation. Within this introduction, it has covered several of the most popular algorithms that are adopted in ALM and also has given their implementation models. Along with the introduction, it also has made sever import comparisons between IP layer multicase and ALM. Finally, an evaluation system is raised for determining the overall performance level of an ALM project.