THREE-TIER ARCHITECTURE

THREE-TIER ARCHITECTURE To design a system for mobile computing, we need to keep in mind that the system will be used through any network, any bearer, any agent and any device. To have a univer-sal access, it is desirable that the server is connected to a ubiquitous network like the Internet. To have an access from any device, a web browser is desirable. The reason is simple; web browsers are ubiquitous, we get a browser in any computer. The browser agent can be Internet Explorer or Netscape Navigator or Mozila or any other standard Mobile Computing Architecture 39 agent. Also, the system should preferably be context aware. We will discuss context awareness later. We have introduced the concept of three-tier architecture. We have also discussed why it is necessary to go for Internet and three-tier architecture for mobile computing. The important question is what a mobile three-tier application actually should consist of. Figure 2.2 depicts a three-tier architecture for a mobile computing environment. These tiers are presentation tier, application tier and data tier. Depending upon the situation, these layers can be further sub layered.