If a host moves from one network to another, its IP address must change.
This chapter introduces some of the key concepts of mobility, setting the stage for later detailed discussion of mobile WAN systems. Although the emphasis of this book is CDPD, this chapter presents a more generalized and abstract view of mobility.
Previous books on the subject of mobile data communications have covered wirelessness1.1 more than mobility. Our intent is to begin from a data networking perspective, independent of media-specific considerations, then consider the effects of media on networking technology. Indeed, one of the primary conclusions of this book is that mobility is most naturally handled in the network layer (Layer 3) and so any discussion of mobility should begin there.