What is WWW, Connection-Oriented Versus Connectionless Communication

What is WWW

A technical definition of the World Wide Web is: all the resources and users on the Internet that are using the Hypertext Transfer Protocol (HTTP).
A broader definition is:
"The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge."
Actually, World Wide Web is a distributed information system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web. World Wide Web is not synonymous with the Internet!
There are several applications called Web browsers that make it easy to access the World Wide Web; Two of the most popular being Netscape Navigator (Mozilla) and Microsoft's Internet Explorer.

Connection-Oriented Versus Connectionless Communication

Transport protocols are used to deliver information from one port to another and thereby enable communication between application programs. They use either a connection-oriented or connectionless method of communication. TCP is a connection-oriented protocol and UDP is a connectionless transport protocol.
The TCP connection-oriented protocol establishes a communication link between a source port/IP address and a destination port/IP address. The ports are bound together via this link until the connection is terminated and the link is broken. An example of a connection-oriented protocol is a telephone conversation. A telephone connection is established, communication takes place, and then the connection is terminated.
The reliability of the communication between the source and destination programs is ensured through error-detection and error-correction mechanisms that are implemented within TCP. TCP implements the connection as a stream of bytes from source to destination. This feature allows the use of the stream I/O classes provided by java.io.
The UDP connectionless protocol differs from the TCP connection-oriented protocol in that it does not establish a link for the duration of the connection. An example of a connectionless protocol is postal mail. To mail something, you just write down a destination address (and an optional return address) on the envelope of the item you're sending and drop it in a mailbox. When using UDP, an application program writes the destination port and IP address on a datagram and then sends the datagram to its destination. UDP is less reliable than TCP because there are no delivery-assurance or error-detection and -correction mechanisms built into the protocol.
Application protocols such as FTP, SMTP, and HTTP use TCP to provide reliable, stream-based communication between client and server programs. Other protocols, such as the Time Protocol, use UDP because speed of delivery is more important than end-to-end reliability.