IPv6 Anycast Routing aware of a Service Flow

Anycast service provides load-balancing since giving a user a connection to the nearest server, and also improves the server´s bandwidth and quality of a service. It maintains the continuity of a service in a failure and prevents damages from instability, DoS attacks against a server, and etc. As kinds of service become various gradually in the Internet environment, the demand for the anycast service has been increased due to these advantages. However the anycast service is a staeless service, it is suitable for the application using UDP protocol. The anycast service is unable to guarantee that the multiple anycast datagram are delivered to the same host, so it is disadvantageous in providing the communication with the fixed server, Fragment, the encryption, and an authentication, and an application using either UDP flow or continuous TCP connection. In this paper, we propose IPv6 anycast routing method for guaranteeing the continuity of the service flow. The key idea to our proposal is to use IPv6 extension headers for continuous service without modification of upper-layer protocol. The anycast route has to be propagated through routing protocols so that the packet destined for the anycast address is routed to an anycast server. We propose the method of IPv6 anycast address advertisement from the anycast server to adjacent routers within local networks.