What is Computer Network ?

when more than one computer is connected by some medium and the information is shared than this technique is called network.
Each device (computer) connected to the network is called a node. and the computer which provides resources for the network is called the server.
Nodes, ie your computer, require a medium to connect to the network  and  these medium includes cable, optic fiber cable, wifi, bluetooth etc. and network devices are also used. like- Router, Switch, Hub, Bridge etc.

Diagram of Computer Network :

Fig : Computer Network 

Features of Computer Network 

  • File Sharing
  • Security
  • User Communication
  • Scalability
  • Reliability
1. File Sharing :
File Sharing is the most common function provided by the network and involves grouping all data files together on a server or servers. 
operating systems also help restrict restricted access to these files only for authorized personnel, ie those who have the rights to work on the system (authorized personnel).

2. Security :
Network security is a process by which a network is protected from unauthorized access (access without permission), hacking and daniel of service attack (DOD), viruses, worms etc.
Network security is not implemented by everyone, it requires experts.
To increase network security in a network, we should monitor the network, use software and hardware components. Such as firewall, antivirus software, IDS etc.

3. User Communication :
Network provide a User communication platform. we can communicate one place to another place through text message, emails, video conferencing, etc.

4. Scalability :
Scalability is very important feature of network. we can add the new components on the network. Network should be scalable because we can extend the network by adding new devices.

5. Reliability :
Reliability means should not be any failure in the network or if it occurs the recovery from a failure should be fast.

Type of Computer Network


  • PAN
  • LAN
  • MAN
  • WAN
1. PAN :

 PAN is refers to “Personal Area Network”. It is a computer network that works to connect the work space of a personal person. PAN works for data transmission between many Networking devices such as computers, mobiles, tablets etc.
Example : Bluetooth is a personal area network, but it is a wireless PAN that works by transferring data using radio waves.



Advantages :
  • PAN is easy to use.
  • It is very reliable.
  • Connect to many devices at a time.
  • No extra space requires.
Disadvantages :
  • PAN Have limited range.
  • Transfer of data is slow.
  • PAN can be used only for personal area.
2. LAN :

Its full name is Local Area Network. It is a network that is used to connect two or more computers.
This network serves to connect network devices over short distances. LANs are used in small buildings, schools, homes, offices etc.
This network is managed or used by one person or one organization. The LAN can be enabled via WiFi or Ethernet. When you share your WiFi connection with someone else, LAN is also enabled here.


Advantages :
  • Resource Sharing
  • Easier to Control
  • High Data Transfer Speed
  • Data Security
  • Internet Sharing

Disadvantages :

  • High maintenance cost
  • Data security Threat
  • Range Limited Area

3. MAN :

MAN is refers to “Metropolitan Area Network”. It works to connect more area than network LAN and some less area from WAN. A CITY  can be connected by this. A MAN network is made up of multiple LANs.
It is used to transfer data from high speed within a city. The best example of this is: Cable TV.

Advantages :

  • It can connect more network devices than LANs.
  • It provide higher security compare to WAN.
  • Its range is more than that of LAN.
  • Easy to implements.

Disadvantages :

  • Difficult to mange.
  • More cable required.

4. WAN :

WAN is refers to "Wide Area Network". It is a collection of many LANs whose range is much more than LAN and MAN. It works to connect a city or a country or a country abroad. This network connects many similar networks such as many LANs and MANs,
The best example of this is: Internet, through this network, people can connect to computers or users placed from one place or one computer anywhere in the world. It is implemented by public transmission system or private network.
Advantages :
  • Through this, we can transfer data all over the world.
  • Shares software and resources with connecting workstations.

Disadvantages :

  • High setup costs.
  • Security issues.