The three tiers that are present in this architecture are as follows:

• The presentation tier
• The application or business logic tier
• Data tier

The diagram depicting the three-tier client-server architecture is as follows:

In a three-tier architecture, the different layers are developed and maintained as different modules, sometimes on different platforms as well. The following are the functions of each layer:

• Presentation tier: This is the first and topmost layer which is present in the application. This tier provides presentation services, that is presentation, of content to the end user through GUI. ...