A Local Area Network (LAN) is a group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area

A Wide Area Network (WAN) is a computer network that spans a relatively large geographical area (diameter of about 200 km)

GAN (Global Area Network) A network spanning a between geographically distinct cities

Server based (client/server):Computers set up to be primary providers of services such as file service or mail service.

The computers providing the service are called servers

The computers that request and use the service are called client computers.

Peer-to-peer

Various computers on the network can act both as clients and servers.

Example Many Microsoft Windows based computers allow file and print sharing.

Many networks are combination peer-to-peer and server based networks.

Network topology is the arrangement or mapping of the elements (links, nodes, etc.) of a network, especially the physical (real) and logical (virtual) interconnections between nodes .

There are three basic categories of network topologies:

Here are some physical topology

The simplest topology is a permanent link between two endpoints. Switched point-to-point topologies are the basic model of conventional telephony. The value of a permanent point-to-point network is the value of guaranteed, or nearly so, communications between the two endpoints. The value of an on-demand point-to-point connection is proportional to the number of potential pairs of subscribers.

Figure 1: Network Topology (Point to Point)

Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network.

Figure 2: Network Topology (Broadcast)

The history of the Internet dates back to the early development of communication networks. The idea of a computer network intended to allow general communication between users of various computers has developed through a large number of stages. The melting pot of developments brought together the network of networks that we know as the Internet. This included both technological developments, as well as the merging together of existing network infrastructure and telecommunication systems.

The earliest versions of these ideas appeared in the late 1950s. Practical implementations of the concepts began during the late 1960s and 1970s. By the 1980s, technologies we would now recognize as the basis of the modern Internet began to spread over the globe. In the 1990s the introduction of the World Wide Web saw its use become commonplace.

The Internet or the World Wide Web is indeed a wonderful and amazing addition in our lives. The Internet can be known as a kind of global meeting place where people from all parts of the world can come together. The major advantages of the internet are:

Before you can connect to the Internet and access the World Wide Web, you need to have certain equipment: