TCP-R: TCP mobility support for continuous operation

The TCP-R (TCP Redirection) is an extension of TCP, which maintains active TCP connections when the disconnection occurs due to the change of the IP address or the change of the network device. In mobile computing environments, the IP address may be changed frequently as the host moves across subnets or changes a network device. However, it is difficult for most network applications to work continuously in such a situation. There is much research to support such dynamics in the network layer, but these attempts in the IP layer tend to incur some complexity. This paper is intended as an investigation of the end-to-end mobility support in transport layer. We developed the simple and secure redirection mechanism in TCP, which enables us to keep our working activities without any intermediate agents. We also show that TCP-R can serve as a solution to the retransmission timeout problem which frequently occurs in mobile environments. We implemented and evaluated a prototype of TCP-R by modifying FreeBSD. The measured performance indicates that TCP-R can maintain operation continuously with minimal overhead and complexity.