Question

The same student is curious about how a Web site appears on his computer screen. On a separate piece of paper, draw and explain the communication between a client and a server when the client requests a Web page; use the OSI model as a reference. For example, what Application layer protocol is required?How will the process differ if the student is sending or retrieving information to or from a secure Web site?

Answer 1

Answer:

HTTP is the application layer protocol required.

Explanation:

For a web page to be displayed on a browser, the seven layers of the OSI model work together. On the application layer, HTTP protocol is used to communicate between the server and the client. The HTTP client is the browser (Chrome, Internet Explorer, Firefox etc.) which sends a request to the HTTP server for accessing a web page.  

When a URL is accessed, the HTTP client sends a request to the HTTP server. The server locates the file which is being requested and sends a response message containing the web page which is to be displayed. The exchange of data between the HTTP client and server takes place over a TCP connection.

TCP is a transport layer protocol which provides a reliable connection over which the exchange of data takes place. Data at the transport layer is sent in the form of segments. If the data being sent from the server is too long, it is divided into multiple segments and sent one after the other. The client is then responsible for joining the segments and displaying the information as a web page. The transport layer is also responsible for error correction and detection during the communication process.

If the student is sending or retrieving information from a secure website, the messages being exchanged between the client and server will be encrypted. This means that if a third-party tries to tap the communication process, they would not be able to decipher the messages. This increases the security and helps keep the information present on the web page confidential.