Analysis and experimentation over eterogeneous wireless networks

Wireless and mobile networks represent an enabling technology for ubiquitous access to information systems. However, there are critical issues that still prevent the widespread use of these technologies. In this paper we analyze and discuss our experience over a real ubiquitous network testbed capable to provide a seamless hand-off among heterogeneous networks. We describe Mobile IPv6/IPv4 interoperability and an efficient mechanism, based on link-layer information, for a seamless handoff among wired and wireless networks. We present the solutions adopted in setting up a real testbed and provide an evaluation of the observed performance, including a characterization of interoperability among three wireless access network technologies: 802.11 WLAN, GPRS, and UMTS.