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In this article:
- What are computer networks?
- History of computer networks
- Devices used in computer networks
- Types of computer networks
What are computer networks?
A computer network can be defined as two or more computers connected to each other such that they can exchange information with each other. Computer networking is the science dealing with computer networks, their working and their functions. Computer networking may also be seen as a sub-discipline of telecommunications.
Computer networks are one of the most important means of communication in the world today. At a time, loads of information can be carried from one computer to another. In this way, computer networks play an important role in the way we transfer information from one place to another.
History of Computer Networks
The desire to connect two computers dates back to the time of the Intergalactic Network developed by J.C.R. Licklider in 1963 which was actually a predecessor of ARPANet. However, the first network was came to reality in 1940, when George Stibitz sent instructions from a teletype machine at Dartmouth College, New Hampshire to his Complex Number Calculator in New Your and received results back through the same way. ARPANet, which developed into the Internet and eventually the World Wide Web, was started in 1969 when the University of California in Los Angeles, SRI in Stanford, the University of California at Santa Barbara and the University of Utah were connected for the first time.
Devices used in computer networks
Computer networks require the use of devices that help them connect computer in a network (called ‘clients’) to each other.
- Modem
A Modem or a Modulator-Demodulator is a device that modulates analog signals to carry digital information and also demodulates such analog signals to derive information from them. A modem is necessary in order to convert digital information into a signal that can be easily carried over a cable (necessarily analog).
- Hub
A Hub or more specifically an Ethernet Hub is a device that is used to connect twisted pair or optical Ethernet devices such that they act as being one.
- Router
A router is an important computer networking devices that is used to forward data packets across an internetwork, that is, a network of networks. The process of forwarding such packets through a router is called routing.
- Bridge
A bridge is another computer networking device that connects multiple networks to each other using bridging technique.
Types of Networks
There are various ways to classify networks. Networks may be classified on the basis of their topology, scale or functional relationships. All the classifications are explained below:
- By topology:
- Bus Network
In a bus network, clients are connected using a common communication line or channel called a bus. It is considered the simplest of connecting computers to each other. This is shown below:
- Star Network
A start network is one where there is a central switch or hub computer and clients are connected to it. It is the most common way of connecting computers with each other. This is shown below:
- Ring Network
A ring network is one where the clients or nodes are connected in such a way that they form a ring. Token ring network is an example of such a network. This is shown below:
- Mesh Network
A mesh network is one where nodes or clients are not connected in a particular pattern. In a mesh network, data keeps ‘hopping’ or ‘jumping’ from node to node until it reaches its final destination. This is shown below:
- By Scale:
- Local Area Network or LAN
A LAN is a network that spans across a small area, mostly a building or an office. LANs usually use Ethernet or Wi-Fi technology to connect computers to each other.
- Metropolitan Area Network or MAN
A MAN is a network that spans a whole city and makes use of either wireless means or optical fiber connections to link the nodes or clients.
- Wide Area Network or WAN
A WAN is an extremely complicated network of computers that covers a very wide geographical area often spreading across countries and continents. The best example of such a network is the Internet.
- By Functional Relationship:
- Client Server Networks
- Peer to Peer Networks
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