Fast VPN mobility across Wi-Fi hotspots

Abstract

Wi-Fi hotspots deployed by domestic networks are an attractive approach to foster ubiquitous Internet access for mobile computers. However, it raises several security issues, since the owners of such hotspots cannot be trusted to be honest; therefore, visitors should consider them as potential Man-in-the-Middle attackers. On the other hand, the owners of such hotspots should not be legally accounted for illegal or unethical activities performed by visitors. We defend that both issues can be tackled by using a VPN-based access architecture for visitors. However, current VPN solutions do not handle gracefully the mobility of clients, an interesting possibility to navigate in a sea of user-provided hotspots. In this paper, we propose a modification of OpenVPN, a very effective and secure, open-source VPN solution, to support the seamless mobility of VPN clients. The proposed modification allows OpenVPN tunnels to be reconfigured as soon as possible after a client handover, in order to minimize outage delays and traffic losses. Performance evaluation with an implemented prototype in different test scenarios showed that we can reduce the handover delay imposed at the VPN level down to 1.7% of the current value, at least.