Design and implementation of optimal route selection mechanism for outbound connections on IPv6 multihoming environment

The Internet has been widely deployed as an infrastructure to provide various ICT (Information and Communication Technology) services today. Some typical services such as e-mail, SNS (Social Network Service) and WWW rely considerably on the Internet in terms of reliability and effectiveness. In this paper, we focus on the IPv6 site multihoming technology and its collaboration with route selection mechanism, which have been reported as one solution to accomplish these goals. Even if a host can easily obtain multiple IP addresses in IPv6 multihomed site, it has to select a proper site-exit router when sending out a packet in order to avoid ingress filtering. Especially, when an inside host initializes an outbound connection it can barely select a proper site-exit router based on its source IP address. To solve this problem, we propose an optimal route selection method for IPv6 multihomed site. With this method, a middleware will be deployed within each inside host so as to connect to the destination host through multiple site-exit router during the initialization phase simultaneously, and then use the first established one for data communication. We also embedded a kind of Network Address Translation (NAT) feature into the middleware to avoid the ingress filtering. By analyzing the results of our experiments on the prototype system we confirmed that the proposed method worked as well as we expected and the collaboration of the site multihoming technology and the proper route selection method can be one possible solution for IPv6 site multihoming in a real network environment.