Editing Client–server model (section)

==Example==
When a [[bank]] customer accesses [[online banking]] services with a [[web browser]] (the client), the client initiates a request to the bank's web server. The customer's [[login]] [[credential]]s are compared against a [[database]], and the webserver accesses that [[database server]] as a client. An [[application server]] interprets the returned data by applying the bank's [[business logic]] and provides the [[Input/output|output]] to the webserver. Finally, the webserver returns the result to the client web browser for display.

In each step of this sequence of client–server message exchanges, a computer processes a request and returns data. This is the request-response messaging pattern. When all the requests are met, the sequence is complete.

This example illustrates a [[design pattern]] applicable to the client–server model: [[separation of concerns]].