Challenges for nomadic computing: Mobility management and wireless communications

In this paper, we present several challenges and innovative approaches to support nomadic computing. The nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. Furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. We consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network-based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre-fetching and caching of critical data. We examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.