IPv6中通过应用层解决Anycast扩展局限性的方案

IPv6以两种方式提供Anycast服务：(1)将Anycast组成员限制在共享一个地址前缀的特殊拓扑区内；(2)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组数成比例增长，从而成了Anycast的扩展性问题。该文提出了一种在应用层实现Anycast服务的解决方案，不仅解决了Anycast服务的扩展性问题，同时也解决了IP层实现Anycast服务所存在的一些其他问题，如路由表膨胀、TCP通信失败等。分析和讨论了该方案的可行性及其有效性，并且根据实验数据对本方案的服务性能进行了分析和总结。

Scheme of Solving Anycast Scalability on Application Layer in IPv6

The existing designs for providing Anycast services are either by confining each Anycast group to a preconfigured topological region or by globally distributing routes to individual Anycast group which causes the routing tables to grow proportionally to the number of all global Anycast groups in the entire Internet to result in Anycast scalability problem, both of which restrict and hinder the application and development of Anycast services. A new scheme of implementing Anycast service is proposed and it solves both Anycast scalability and other existing problems, such as router table explosion, TCP communication errors, and so on, which are generally caused by performing Anycast services on IP layer. The feasibility and validity of this new scheme are analyzed and discussed. Meanwhile, the performance of this scheme is analyzed according to experimental data.