Basic Components of Networks

A computer network is a collection of interconnected devices that can communicate with each other, exchange data and share resources. A network has five basic components, namely clients, servers, channels, interface devices, and operating systems.

Servers

Servers or Host computers are powerful computers that store data or applications and connect to resources that are shared by the users of a network.

• They act as a central repository for all the data and applications used by the network.
• Some common examples of servers are file servers, print servers, web servers, and mail servers.

Servers can be classified based on their functionality, such as application servers, database servers, and domain name servers.

Clients

A client is the computer used by the users of the network to access the servers and shared resources (such as hard disks and printers). So, a personal computer is a client. Clients can be classified based on their functionality, such as thin clients and thick clients. Thin clients are lightweight computers that rely on the server to perform most of the processing, whereas thick clients have their own processing power and can run applications locally.

Channels

The technical name of channels is a network circuit. It is the pathway over which information travels between the different computers (clients and servers) that comprise the network. Channels can be classified based on their transmission medium, transmission rate or bandwidth, transmission directional capability, and the type of the signal.

• Transmission medium is the physical medium of the channel, which can be either wireline or wireless. The wireline is called the guided media or line-based media. The wireline is of several kinds such as twisted pair wire, coaxial cable, and fiber optic cable. In wireless media, there is no physical wire along which information travels, and the information is transmitted without wires from one transmission station to the next. Common examples are radio, mobile networks, microwave, and satellite.
• Transmission rate or bandwidth shows how fast information can be transmitted over the channel. It is measured in bits per second (bps). The higher the bandwidth, the more data can be transmitted in a given amount of time.
• Transmission directional capability refers to the direction in which information can be transmitted over a channel. It can be simplex, half-duplex, or full-duplex. Simplex means that information can be transmitted only in one direction. Half-duplex means that information can be transmitted in both directions, but only in one direction at a time. Full-duplex means that information can be transmitted in both directions simultaneously.

Signal type can be analog and digital. Analog signals are ‘continuous’ (they take on a wide range of values) and digital signals are ‘discrete’ and binary (take on only two values). Digital signals are more suitable for computer networks because computers represent all information in binary.

Interface Devices

The devices that connect clients and servers (and sometimes other networks) to the channel are called interface devices. The common examples are modems and network interface cards. Network interface cards (NICs) are hardware devices that are installed in a client or server and provide a physical connection to the network. Modems are used to connect to remote networks or the Internet through a telephone line.

Operating Systems

This is the Network Software. It serves the same purpose that the operating system serves in a stand-alone computer. The operating system controls the overall functioning of the network, including managing resources, scheduling tasks, and handling security. Some common examples of network operating systems are Windows Server, Linux, and Unix.