Network applications are software programs that run between different computers connected together on a network.

Network applications

Network applications are software programs that run between different computers connected together on a network.

Some of the more common uses of network applications include using a web browser program to find content from the World Wide Web, or using an e-mail program to send e-mails over the Internet.

Network applications are selected based on the type of work that needs to be done. A complete set of application-layer programs is available to interface with the Internet. Each application program type is associated with its own application protocol. Some examples include:

• HTTP is the World-Wide-Web communications protocol used to connect to web servers. Its primary function is to establish a connection with a web server and transmit HTML pages to the client browser.
• Post Office Protocol 3 (POP3) is an application-layer protocol supported by e-mail programs for the retrieval of electronic mail. POP3 is a standard e-mail server commonly used on the Internet. It provides a message storage container that holds incoming e-mail until users log on and download their messages.
• File Transfer Protocol (FTP) is a simple file utility program for transferring files between remote computers, which also provides for basic user authentication.
• Telnet is a remote access application and protocol for connecting to remote computer consoles, which also provides for basic user authentication. Telnet is not a graphical user interface but is command-line driven or character mode only.
• Simple Network Management Protocol (SNMP) is used by network management programs for monitoring the network device status and activities.

It is important to emphasize that the application layer is just another protocol layer in the OSI model or TCP/IP protocol stack. The programs interface with application layer protocols.

Sending e-mail

E-mail client applications, (such as Eudora, Microsoft Mail, Pegasus, and Netscape Mail) all work with the POP3 protocol. The same principle is true with web browsers. The two most popular web browsers are Microsoft Internet Explorer and Netscape Communicator. The appearance of these two web browser programs is very different, but they both work with the application layer HTTP protocol.

Electronic mail enables you to send messages between connected computers. The procedure for sending an e-mail document involves two separate processes – sending the e-mail to the user’s post office, which is a computer running the POP3 server software, and delivering the e-mail from that post office to the user’s e-mail client computer, which is the recipient.