AAA and Network Security for Mobile Access: Radius, Diameter, EAP, PKI and IP Mobility

11.1. Operator Co-existence and Agreements

Once, there was a time when carrying a mobile phone of half the size of a car battery was considered a revolutionary way of communicating. As cellular phones shrank in size and information started flowing in a variety of forms, such as short messaging, files, pictures, staying connected through wireless channels has started posing new demands. People are starting to ask, why not connect their computers to the Internet or their work network wirelessly when they are out of their home or office environment? Partly the limited bandwidth capacity, partly the costly set-up of a cellular network (both in the form of spectrum and equipment), started a new trend: new access technologies that are cheaper and offer more bandwidth than cellular are being developed. Unfortunately many of these networks, due to their engineering characteristics, may have limited scope and feasibility. For instance, 802.11 networks still lack the support for high-speed spatial mobility that cellular networks provide, while the relevantly high bandwidth services that these networks provide make them excellent candidates for local area networks with limited coverage and support for mobility. A hotel could install such a local network to offer high-bandwidth connectivity for its guests in the lobby, while the guests still expect to use their cellular phones for conversations or low-bandwidth data transfers while driving outdoors. When those same guests arrive home, they ...