Web Technologies - Old Questions
2. List the protocols and their use at the application layer in the Internet. Why World Wide Web is use? Explain.
An application layer protocol defines how application processes (clients and servers), running on different end systems, pass messages to each other. Some protocols used in application layer are discussed below:
1. HTTP (Hypertext Transfer Protocol):
This is a protocol used mainly to access data on the world wide web(WWW). It is a protocol which governs the communication between the client and server.
2. TELNET (Terminal Network):
TELNET is a client-server application that allows a user to log onto remote machine and lets the user to access any application program on a remote computer.
3. FTP (File Transfer Protocol):
FTP is the standard mechanism provided by TCP/IP for transferring a file from one host to another. Transferring file from a client computer to a server computer is called uploading and transferring from server to a client is downloading.
4. SMTP (Simple Mail Transfer Protocol)
The TCP/IP protocol that supports electronic mail on the internet is called SMTP. It transfers messages from senders' mail servers to the recipents' mail servers using TCP connections. SMTP provides services for mail exchange between users on the same or different computers.
5. POP (Post Office Protocol):
This is a protocol used by a mail server in conjunction with SMTP to receive and holds mail for hosts. POP3 mail server receives e-mails and filters them into the appropriate user folders. When a user connects to the mail server to retrieve his mail, the messages are downloaded from mail server to the user's hard disk.
The World Wide Web (WWW) is a system that we use to access the Internet. The WWW is hypertext based information retrieval tool, it uses the hypertext to access the various forms of information available on the world’s different networks. One can easily surf the Web by jumping from one document to another using the links in those documents. These documents can be in many formats, such as text, graphics, animation, sound and latest is video. They may also be a combination of all these. All the information on Internet are presented to the user as a document or more popularly known as Web Page. All these Web Pages are link to each other or even to section within a Web Page. And these links are known as Hyper Links.