Computer NETWORK

Introduction

What is a computer Network?

A computer network 
It is the connection of two or more computers over a shared medium (cabled or wireless) with a purpose of sharing resources such as software or hardware.
Example of hard wares shared on the network there is CDROM Drives, Printers, Hard disk partitions, Server Machines
For Example

When networks at multiple locations are connected using services available from phone companies, people can send e-mail, share links to the global Internet, or conduct video conferences in real time with other remote users. When a network becomes open sourced it can be managed properly with online collaboration software. As companies rely on applications like electronic mail and database management for core business operations, computer networking becomes increasingly more important.

Every network includes:

    At least two computers




    Networking Interface Card's (NIC) 
                       

Cabled Network Interface card (LAN)                                    Network Interface card for Wireless computers (W LAN)

A connection medium, usually a wire or cable, although wireless communication between networked computers and peripherals is also possible.

 Network operating system software, such as Microsoft Windows NT or 2000, Novell NetWare, UNIX and Linux.

              TYPES OF COMPUTER NETWORKS

Common types of area networks are:

1. LAN - Local Area Network.
2. WAN - Wide Area Network.
3. W LAN - Wireless Local Area Network.
4. MAN - Metropolitan Area Network.
5. SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network.

They're three important groups of networks which are commonly used in computer networking 

LAN, MAN,WAN

LANs (Local Area Networks)

These are privately owned networks. like company network, a school network or any organisation located in same geographical area.

LAN are networks usually confined to a geographic area, such as a single building or a college campus. 

LAN can be small, linking as few as three computers, 

Extended LAN often links hundreds of computers used by thousands of people. 

MANs (Metropolitan area Networks)
It’s a type of network which links cities and towns. It is used by companies to interlink their offices located in different cities and towns.

The technology used in MAN is VPN

VPN (Virtual Private Network) 

VPN uses a technique known as tunneling to transfer data securely on the Internet to a remote access server on your workplace network. Using a VPN helps you save money by using the public Internet instead of making long–distance phone calls to connect securely with your private network. There are two ways to create a VPN connection, by dialing an Internet service provider (ISP), or connecting directly to Internet.

WANs (Wide Area Networks)

WAN. It’s a network which  covers a country or a continent, it combines multiple LAN's that are geographically separate. This is accomplished by connecting the different LAN's using services such as dedicated leased phone lines, dial-up phone lines (both synchronous and asynchronous), satellite links, and data packet carrier services. Wide area networking can be as simple as a modem and remote access server for employees to dial into, or it can be as complex as hundreds of branch offices globally linked using special routing protocols and filters to minimize the expense of sending data sent over vast distances.