Supporting global connectivity in heterogeneous IP networks

Abstract: Mobility of user devices connecting to the Internet is of major interest in today's research in networking. Users with portable devices, like laptops and personal digital assistants (PDA), connecting to foreign networks in the Internet want the same functionality as when connected to the home network as well as accessibility through the home IP address. For the users as well as for the applications, network mobility should be transparent. To achieve this transparency, the Mobile IP is deployed. Connecting wireless devices through an access point for network access enables mobility. Geographical areas are covered with wireless high bandwidth connections, creating so-called hot spot areas. The access points may have different capabilities, be connected to different networks and be installed by different providers. A mobile host will sense multiple access points in this environment. To make use of the dynamic capability, a device should be able to use the best available connectivity for a network flow and perhaps different connections for different flows. In hot spot areas it may be difficult to cover everything with good radio coverage, and therefore a mobile host may have to use an intermediate, peer mobile host for connectivity to an access point. Also, co-operating mobile users who require connectivity between their devices, should be able to quickly and easily establish a multi-hop ad hoc network between them. This thesis proposes and describes a number of solutions towards enhancing network connectivity in wireless broadband network areas, where the networking software will evaluate and decide which wireless network connections to use. Multi-hop ad hoc connections can be used between peers and in the connecting to access points. Modifications are proposed to Mobile IP to manage multihoming of a mobile host simultaneously connecting it to multiple access points. The connectivity between mobile hosts and access points is evaluated to enable usage of the best connections. The mobile host, the home agent and the correspondent host are able to decide on which network connections to use. A gateway is proposed to enable a reactive ad-hoc routing protocol to interoperate with wired IP networks and to support mobility of hosts between ad hoc networks.