Like humans, computers also communicate. Communication between computers is achieved through networking. The figure shows a computer network where the computers and other devices (like printers) are connected through a cable. Note that computers in a network can also be connected with satellite links, radio, and so on.
Computer networks are the interconnection between computers that allow sharing of information between two or more computers. Computer networks enable sharing of resources between various computers with different operating systems, which are placed at different locations.
Need For Computer Network:
USSR and USA were involved in a cold war in 1960. To send some urgent messages to its armed forces, the USA used the medium of electronic text to communicate with their head offices. Similarly, the disaster of Titanic could have been prevented or the rescue operations could have been intensified, had the communication been done on time.
It’s very important to have a good communication network. It serves several purposes like keeping you updated with election results, Nasdaq 100 in the share market, launching of a new product, etc.
Characteristics Of Communication:
The characteristics of effective communication in computer networks are listed below.
Data must be delivered to the correct destination.
Data must be delivered error-free.
Data must be delivered on time.
Types of Computer Networks:
Computer networks may be classified according to a wide variety of characteristics such as the medium used to transport the data, communications protocol used, scale, topology, organizational scope, etc. Computer networks are now rapidly used by the all levels of society, like government bodies, schools, colleges, and private sector, etc. There are many types of computer networks, some of the important ones are described below:
Local Area Network (LAN):
LAN is confined to a small geographical area, like a building or group of buildings. The data transfer rate of the Local Area Network is very high even faster than data transmitted through telephone lines. It’s a group of computers all belonging to the same organization, and are linked within a small geographic area using a network. At the security purpose level, it is not trustworthy because, for example, an employee of an organization can change the important data of the organization. Due to its small size, one person can administrate a Local Area Network. The defining characteristics of LANs, in contrast to Wide Area Networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of need for leased telecommunication lines.
In a LAN, one computer is selected as the file server which controls and stores all the software shared by different computers in the network. All the other computers, which are attached to the file server, are known as workstations. These workstations have their own software. The workstations and the file servers in a LAN are connected using cables. Note that a Local Area Network can be wireless also. In a wireless connection, communication is done using the wireless medium (communication channel) such as radio waves, infrared, etc.
Advantages of Local Area Network:
Following are the advantages of the Local Area Network.
Provides a rapid method for sharing and transferring files.
Allows an easier upgrading of the program as changes are done on the file server instead of all the individual workstations.
Enables printers, facsimile (FAX) machines, modems, scanners and CD-ROM players or similar peripherals to be shared by many users when connected to a network.
Metropolitan Area Network (MAN):
Metropolitan Area Network or MAN is basically spread throughout a city, college campus, or a small region. MANs are larger than LANs, and it enables their users to share information throughout the city. It is commonly used by schools, campuses, hospitals, large universities, large companies, etc.
To understand the functions of the Metropolitan Area Network, let us consider an example. A company called XYZ has headquarters in the USA. One of its branches called ABC is in North Extension. A Metropolitan Area Network enables people at these two places to easily communicate or send data from a branch to the headquarters and vice versa.
Advantages of Metropolitan Area Network:
Following are the advantages of the Metropolitan Area Network.
Transfers data at a high speed.
Recovers fast from network faults.
Provide real-time transaction backup systems.
Wide Area Network (WAN):
WAN is a network that connects computers over long distances like cities, countries, continents, or worldwide. Wide Area Network uses public, leased, or private communication links to spread over long distances. Wide Area Network uses telephone lines, satellite links, and radio links to connect. The need to be able to connect any number of computers at any number of sites results in WAN technologies. The primary objective of a Wide Area Network is to exchange information quickly and in a cost-effective manner. Note that a WAN can also be an interconnected LAN and MAN.
Advantages of Wide Area Network:
Following are the advantages of the Wide Area Network.
Facilitates a centralized company backup.
Offers flexibility of location as people using the same data do not have to work at the same site.
Enhances communication through the use of email and file sharing.
Uses of the Computer Networks:
Computer networks play a major role in providing information to large, and small organizations as well as to the common man. Nowadays almost all companies, banks, and stores have implemented computerized transactions. It may be on the same campus, building, city, or at different places or cities. For all these purposes computer networks are used.
The most common uses of computer networks are:
(1) Resource Sharing- The primary aim of networking is to share resources regardless of the physical location for better communication. Resource sharing involves both hardware and software sharing as computers are interconnected. Simply resource sharing is sharing such as printers, scanners, PDAs, fax machines, and modems. For example, many computers can access one printer if it is in a network.
(2) Easy Mode of Communication- Using computer networks, we can interact with different people with each other all over the world. It provides powerful communication among widely separated employees, teams, and sections. They can easily communicate at a very low cost via mobile, social media, telephone, e-mail, chatting, video telephone, video conferencing, SMS, MMS, groupware, etc.
(3) Cost Effective- Due to the interconnection of computers, it is easier to access and transfer a large amount of data from a far distance in a cost-effective manner and a short period.
(4) Backup Facility- Networking provides an easy backup for data. Multiple copies of important files can be kept on different computers of a network.
(5) Reliability- The backup facility in networking makes it a reliable mode for communication and sharing files. In case, the file is unavailable on one computer. It can be accessed from another computer.