Design and Implementation of IP over Bluetooth for IP Mobility Support in a Heterogeneous Environment

Mobility support at the IP layer is proposed by the Internet Engineering Task Force Mobile IP Working Group to define media-independent procedures, whereby a mobile device can maintain existing transport and application-layer connections despite changing its point-of-attachment. Roaming between heterogeneous wireless networks, with different link layers, is therefore possible with this IP mobility support. However, problems arise when incompatible link layers, which could not integrate well with Mobile IP to support seamless handover, are used. In this paper, a Wireless LAN and Bluetooth heterogeneous environment was set up with Mobile IP to demonstrate the problems when the Point-to-Point Protocol is the Bluetooth’s link layer. The main reason is due to the intrinsic properties of the Point-to-Point Protocol. A new method to carry IP packets over Bluetooth, named IPoBT, is designed as a protocol layer between IP and L2CAP, and implemented in the form of a network driver in Linux. This solution is able to overcome the problems in the Point-to-Point Protocol, to integrate well with Mobil IP for providing a better support for seamless handover between the heterogenous networks.