Systems for user and application mobility in wired and wireless networks

On the Concept of Mobility Thewordsmobility andnetwork arefoundtogetherinmanycontexts. Theissuealone ofmodelinggeographicalusermobilityinwirelessnetworkshascountlessapplications. Just to name a few: † resource allocation, typically bandwidth; † pervasive computing, in a world where every object is a computing device that can be of help for persons or other devices; † service continuity: in the Internet realm, this is the case of the various mobile IP solutions, but we can also focus on the lower-level issue of physical hand-ofi, possibly between heterogeneous networks; † location-aware services, from navigation, to advertising; † disruption-tolerant networks, for example in vehicular, military, social, or coop- erative applications. Depending on one’s background, the concept is investigated with very difierent tools and aims. Given also the huge number of works, therefore, it would simply not be practical to cite the \most relevant" contributions to a \fleld" so di–cult to deflne. Nevertheless, for highlighting once more the broadness of the subject, let us cite [1], whereNokia pointsoutthescientiflcand commercial needof considering evencultural factors when answering the \who is doing what and where" question. It may seem that now there is not much to add to the concept of mobility, but it is not so. Actually, the last decade saw also a growing interest in code mobility, i.e. the 9