What is a Network ??
A Network is group or a system of interconnected people or things for the purpose of communication and sharing of information.
At home you may have a computer and printer which are connected to each other but this does not form a network since you are only using it and there is no communication between computers as there is only one computer. Most of the time you may also find that your printer is idle and not being used! But if there were many computer connected together and each having its own printer, it would be waste if they would all be unused most of the times. The group of computers which are connected together can use a common printer !
Thus,a computer network is a group of computers and other devices connected to each other. They share hardware resources as well as software and data. This means that they can work independently and can communicate with each other. They also share hardware resources like printer, scanner, modem, CD Drives etc. The best known computer network is the Internet.
The first network was created in 1969 in USA. The University of California at Los Angeles, the stanford Research Institute, the University of California at Santa Barbara and the University of Utah were connected as a part of Advanced Research Project Agency Network (ARPANET) project. It is this network that evolved to become what we now call the Internet.
Advantages of a Network
- Sharing of hardware resources like hard disk, scanner, printer etc.
- Helps In Communication via e-mail, video conferencing, instant messaging etc.
- Reduce costs – Enables multiple users to share a single hardware device like a printer or scanner.
- Enable all type of file (text, video, audio etc) sharing across the network – many users can access the same file. It also allows sharing of software operating programs on remote systems.
- Efficient storage of data – data can be stored in central network drive which can be shared by everyone.
- Reduces Data Redundancy – duplication of data is reduced as data is stored centrally.
- Data backup is easy as all the data is stored on the file server.
Disadvantages of a Network
- Security issue – since there are many users sharing the same resources, it is important to keep the data secure.
- It is easy for our files on a device to get corrupted by malware which gets transported through the network.
- There are danger of hacking and security measures like firewalls are needed to prevent it.
Components of an Network
When two people or devices are communicating with each other, they need some medium of communication and some device for communicating. In a simple network there may be two computers which are communicating with each other but they always need to be connected to each other with or without wires.
A computer which is connected to a network is called a Node or a Workstation.
1. Network Interface Card (NIC) – Network Interface Card is a device that enables a computer to talk with another computer.
2. Hub and Switch – Hub is the most basic networking device that connects multiple computers or other network devices together. Two computers cannot communicate with each other directly. They need an interface through which they can send or receive data.
3. Cables and Connectors – Ethernet network use the UTP (Unshielded Twisted Pair) cable as it is easy to use and inexpensive for short distances. For longer distances the Fibre Optic cables are used.
4. Modem – Modem stands for Modulator-Demodulator. It enables you to connector computer to the available internet connection over existing telephone line. The modem turns the digital signal of a computer into modulated electrical signals for transmission over telephone lines which are then demodulated by another modem at the receiver and into digital data.
5.Router – It is a device used to connect to networks or you can see it is used to connect a network with an internet connection. When you have two distinct networks or you want to share a single internet connection with multiple computers we use a router.
Types of Network
Computer Networks can be characterized by their size as well as their purpose. There are different types of computer networks depending upon the number of devices which are connected together. Some of the different types of networks based on size are-
Personal Area Network (PAN)
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
1. Personal Area Network (PAN)
A Personal Area Network is a computer network organized around an individual within a building. This could be inside a small office or home. Normally a PAN would include one or more computers, telephones or mobile phone, peripheral devices like printer, video game consoles.
2. Local Area Network (LAN)
A Local area Network consists of a computer network and office building. A LAN is a very useful for sharing resources such as data storage and printers etc among the people in the building but not with the rest of outside world.
3. Campus Area Network (CAN)
A Campus Area Network is the network of multiple interconnected local area network in a limited geographical area. A CAN is smaller than Wide Area network (WAN) or Metropolitan Area Network. A CAN is also known as corporate area network.
4. Metropolitan Area Network (MAN)
A Metropolitan Area Network consists of a computer network which covers an entire city, college, campus or a small region. A MAN is larger than LAN and can be formed by joining many LAN’S together.
5. Wide Area Network (WAN)
Wide Area Network occupies a very large area such as entire country or the entire world. It consists of many smaller networks such as LAN’S or MAN’S. The speed is slower as compared to LAN.