1. What is Network?
Network is any collection of individual systems that communicate with shared network. Network is a collection of two or more connected systems. When these systems are joined in a network, we can share files and peripherals (i.e.) Printers, modem and backup drives, DVD drives, 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. Computer networking becomes increasingly more important.
Basically networks include:
Two computers Server or Client workstation.
Networking Interface Card’s (NIC).
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 Networks:
LAN: Local Area Networks
Local Area Network is a network that is confined to a relatively small area. It is generally limited to a geographic area such as a college lab, school, or building.
MANs: Metropolitan area Networks
A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN).
The Metropolitan Area Network (MAN) protocols are mostly at the data link level (layer 2 in the OSI model), which are defined by IEEE, ITU-T, etc
WAN: Wide Area Networks.
Wide area networking combines multiple LANs that are geographically separate. Connecting the different LANs 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.
Collection of private computer networks within an organization. It may consist of many interlinked local area networks and also use leased lines in the wide area network, the main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences. An intranet uses TCP/IP, HTTP.
The Internet is a system of linked networks that are worldwide in scope and facilitate data communication services such as remote login, file transfer, electronic mail, the World Wide Web and newsgroups.
VPN: Virtual Private Network
A virtual private network (VPN) is a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization’s network.
VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together.