why

COMPUTER NETWORK :

Two or more autonomous computing devices, connected to one another in order to exchange information or share resources, form a computer network. For example, if in your home, you can connect your smartphone, your laptop with your smart TV, gaming console and a printer simultaneously either using cables or through Wi-Fi, it will be termed as a computer network.

Computer networks are very useful for lots of things. They facilitate resource sharing (resources such as storage, software etc. on the network can be shared), enhanced communication (communicating with devices on a network is easier), cost reduction (resource sharing cuts on costs) and so forth.

Advantages of Networks :-

*Share resources:- such as printers and scanners. This is cheaper and easy to take for each computer.

*Share depository:- being able to access files from any machines on the network can share data.

*Can share software:- software can be to establish centrally rather than on each machine. Metering software can then be used to limit the number of duplicates being run at any one time. This is much affordable than buying licenses for every machine.

*Improve communications:- messages can be sent example, internal email

Disadvantages of Networks:-

1. The system are more sophisticated and complex to run. This can add to costs and, you may need specialist employees to run the network.
2.  If software and files are held centrally, it may be impossible to carry out any work if the central server fails. People becomes reliant on the communication, if these fail, it can cause havoc.
3.  If networks are badly managed, services can become unusable and productivity fails.
4.  File security is more important especially if connected to WAN, for example, defense from ailments.

Components of a Computer Network :-

Merely by joining two computers with a cable won't form a network. In fact, there are many components that together make a network.

Major components of a Computer Networks are:-

• Hosts/Nodes (such as PC, laptops, smartphones etc.)
•  Servers
•  Client
•  Network hardware (such as NIC, router, switch, hub etc.)
•  Communication channel (such as cables, radio-links etc.)
•  Software (such as protocols, network operating system etc.)

1.  Network services (such as BNS, File-sharing etc.)
2.  Hosts or Nodes;- The term host or nodes refers to the computers that are attached to a network and are seeking to share the resources of the network. Of course, if there were no nodes (also called  workstations), there would be no network at all. ***Personal Computers, laptops, handsets, etc. when connect to a network become presenters.***
3.  Server:- A server is a very important computer in a network. A server is superintendent for making the networking tasks happen. In other words, a server facilitates networking tasks like sharing of data, resource - sharing, communication among hosts etc. On small networks, sometimes, all the shareable stuff (like files, software, etc.)is stored on the waiter. A network can have more than one waitperson also. Each server has a unique name on the network, and all users of the network identify the server by its unique name. On big networks, there can be servers dedicated to specialized tasks, for  example, a file server  only handles files' related requests ; a Printer server only handles printing requests and so on.
4.  Clients :- Client is a related term. A client computer is a host computer that appeal for some services from a waiter. In other words, a server computer serves the requests of buyer computers.
5.  Network Hardware :- Other than hosts and writing, a network requires specialized hardware to carry out various roles, such as establishing corrections, controlling network traffic. There are many types of hardware that are required in a network. Some examples of network are:-*NIC (Network Interface Unit). It is a network card attached to a host to establish network connections. Every NIC card has a unique physical address called the MAC address, which is a 6 byte (48 bits) address assigned by the NIC manufacturer. An NIC is also called Network Interface Unit (NIU) or Terminal Access Point (TAP)                                                                                                  *Hub, Switch, router. These are connectivity gadgets. 
6. Communication channel :- Hosts in a network interact with other hosts and server(s) through a communication medium. The communication narrows can either be wired or wireless.
7.  Software:- The software layers of a network make networking possible. These consist of network protocols,  network operating system etc. A protocol refers to a pre-decided set of directive using which all parties of a network connect and interact with one another.  A network operating system is a specialized operating system that can handle networking tasks.
8.  Network Services:- These refer to the applications that provide different functionalities over a network, such as DNS(Domain Name System), File Sharing, VoIP (Voice over IP) and many more.

Types of Network :-

A computer network means a group of 'networked' computers, that is, computers, that are connected by means of a communication system. A network can mean a small group  of linked computers to a chain of a few hundred computers of different types (example, Personal Computers, minis, mainframes etc.) puffed up around the world. Thus, networks vary in size, difficulty and geographical spread.

• LAN:-  Small computer networks that are confirmed to a localized area(example, an office, a building or  a factory) are known as Local Area Network (LAN). The key purpose of a LAN is to service its users in resource sharing. The hardware as well as software resources are shared through LAN. For instance, LAN users can allowance data, information, programs, printers, hard-disks, modems etc.   
• WAN:-  The networks spread across countries or on a very big geographical area known as WAN. A Wide Area Network (WAN) is a group of LAN that are spread across several locations and joined together to look like one big LAN. The WAN link computers to facilitate fast and efficient exchange of information at lesser costs and higher speeds. Computers joined to a wide-area network are often connected through public networks, such as the telephone system. Sometimes they can be joined through leased lines or satellites. The largest WAN in extant is the INTERNET.
• PAN:- A personal area network(PAN) is the interconnection of details of technology devices within the range of an individual person, typically within a range of 10 meters. For example, a person travelling with a laptop, a personal digital assistant (PDA), and a portable printer could interconnect them without having to cork anything in, using some form of wireless technology such as Wi-Fi. Typically, this kind of personal area network could also be interconnected without cable to the Internet or other networks. You can use PAN networks to transfer folders including email and calendar appointments, digital photos and music etc. from your portable devices such as phones and tables to PC and vice versa