Mobility attracts many developers and system designers; it will give us the ability to use our computers with no physical limitations with respect to connections. This thesis will try to introduce the main concepts that define mobile computing in our days. It will identify the challenges that face mobile computing and their impact on current developments in this area. Location management and how the cellular networks function is defined and described. We will conduct a comparison between protocols in location management with respect to network messages and database operations. In the IS-41 model ...