利用多播树实现Anycast服务

IPv6以两种方式提供Anycast服务：一种是将Anycast组成员限制在共享一个地址前缀的特殊拓扑区内；另一个是将Anycast地址表示的共享某个特性的结点组分散在互联网的各个地方，这种方式使得路由表会随全球Anycast组数呈比例增长。无论是哪种方式，它们都存在诸如Anycast可扩展局限性等问题。本文提出了一种建立在Anycast树之上的通信模型，此模型实现了Anycast组成员的动态加入与离开，从真正意义上解决了Anycast现存的扩展性问题，同时此模型实现了Anycast树自身信息与请求的分布式维护与处理，从而实现了均衡负载功能。本文同时深入分析和讨论了该模型的可行性及其有效性，并论证它可以支持大规模的Anycast组的建设。

Implementation of Anycast Service with Multicast Tree

The existing designs for providing Anycast services are either to confine each Anycast group to a preconfig- ured topological region or to globally distribute routes to individual Anycast groups which causes the routing tables to grow proportionally to the number of all global Anycast groups in the entire Internet,both of which restrict and hinder the application and development of Anycast services.A new kind of Anycast communication model is proposed on the basis of Anycast tree in this paper.Since this model achieves dynamic Anycast group and allows Anycast members to freely leave and join Anycast group it radically solves the existing scalability problem.In addition,this model accompli- shes the distributed maintenance and transaction of Anycast service request and the information on Anycast tree so it fulfills the load balance.This paper deeply analyzes and discusses the feasibility and validity of this communication mod- el,and argues that is supports the large-scale Anycast group.