The mobility of users made possible by wireless networks and portable compu-
ters opens up new possibilities, but not without raising some challenges.
When using these technologies, one has to deal with properties like slow but
expensive wireless connection lines, frequent disconnection and limited host
performance. Integration of mobile users and their devices into existing
hardwired networking environments raises many questions which have to be
considered carefully. In this paper, these problems are analyzed to build a
system architecture that aims to answer these questions.