An IP-Decoupling Approach to Host Mobility

Abstract

This paper presents the design, implementation, and performance evaluation of an approach to supporting host mobility in wireless Internet. We observe that an IP address conventionally serves dual purposes: a routing directive in the network-layer and an end-point identity in transport or upper-layers. Such a coupling causes session disruptions when hosts move and affiliate with new IP addresses due to changing points of attachment to the system. As a remedy, we propose to support host mobility by decoupling the IP layer routing directive from the transport layer identification and by introducing a table to maintain the binding of IP addresses to transport-layer identities or vice versa. The binding information can be queried or modified using the current DNS system with secure DNS updates, and can be exchanged directly between two communication peers without any third party’s interventions. Therefore the routing path of our approach is optimized, as opposed to the well-known IETF standard Mobile IPv4. As further quantitative comparisons, we contrast our scheme to Mobile IPv4 and Mobile IPv6 in terms of overhead of packet size and extra processing time in TCP/IP protocol stack, and packet loss during handoffs. Simulation results show that our approach is promising, incurring comparatively least packet overhead than counterpart schemes do. Concerning applicability, our approach is susceptible to easy deployment in a setting of IPv6 networks, or IPv4 and IPv6 co-existent networks. Additionally, our proposal can also be used to support mobility in multi-tier environment such as Wireless LANs and GPRS overlay networks.