Anycast--IP的又一通信模式

Anycast是一种新型的网络服务，是IPv6的一个新特性．与unicast和multicast一样，它是IP的一种通信模式．Anycast给用户的期望是通过一个anycast地址就能访问到该地址所表示的一组服务器中对用户来说距离最近的一个．Anycast的应用空间非常广阔．但是，它的实现还面临着许多问题．现在，anycast研究者的注意力主要集中在路由协议、无状态服务问题、组管理协议、局域网通信、地址结构、安全问题、QoS保证以及可扩展性等方面．有些方面已经取得了一些进展．但是，仍然有许多研究工作有待进一步开展．关于anycast的一些协议和标准正在讨论之中，但仍然没有达成共识．作为下一代Internet新兴的服务方式，anycast为我们展开了广阔的探索空间．

Anycast-Another Communication Model for IP

Anycast is a new internetwork service, and a new feature of IPv6. Just like unicast and multicast, it's a communication model for IP. With anycast service, a client can reach the most appropriate server, which is one of the servers that accept datagrams for the anycast address. Anycast has numerous potential applications, and is recognized as a useful service. However, many technological problems have limited its acceptance by the community. At present, anycast researchers focus on the routing protocol, stateless service, group management, LAN communications, address space, security, QoS, scalability etc. Some progress has been made. But, much work remains to be done. The protocols and standards for anycast are under the discussion, but have not reached a consensus. As a new service of next generation Internet, anycast offers a broad space to explore.