A network is a group of two or more computers that intelligentlyresources with each other. A network can be as small and simple as two computers or as large as the world’s largest network the Internet. It allows us to be able to access a remote resource as if it were a local resource.
Intelligently sharing means that each computer that shares resources with other computers maintains control of that particular resource.
What is Resource?
Any hardware or software device can be shared in the network are called resources. These include the following
Ø File/folder
Ø Printers
Ø Disk Drives
Ø Optical Drives
Ø Modems (Internet Connection Sharing)
Ø Scanners
Advantages of network:
Ø Reduces hardware costs by sharing expensive printers and other peripherals among multiple users
Ø Multiple users can share access to software and data files.
Ø Electronic mail (email) can be sent and received.
Ø Multiple users can contribute to a single document using collaboration features.
Ø Remote-control programs can be used to troubleshoot problems or show new users how to perform a task.
Ø A single Internet connection can be shared among multiple computers
Types of Networks
A. Local area networks.
The smallest office network is referred to as a local area network (LAN). A LAN is formed from computers and components in a single office or building.
B. Home area networks.
A home area network (HAN) is really no different from a LAN. It often uses the same hardware components as a LAN, but a HAN is mainly used to share Internet access.
C. Wide area networks.
LANs in different locations can be connected by high-speed fiber-optic, satellite, or leased phone lines to form a wide area network (WAN).
D. The Internet.
The World Wide Web is the most visible part of the world’s largest network, the Internet. The Internet is really a network of networks, all of which are connected to each other through the TCP/IP protocol. Programs such as web browsers, File Transfer Protocol (FTP) clients, and email clients are some of the most common ways users work with the Internet.
E. Intranets.
Intranets use the same web browsers and other software and the same TCP/IP protocol as the public Internet, but intranets exist as a portion of a company’s private network. Unlike the Internet, the content is restricted to authorized company users only. An intranet is a private Internet.
F. Extranets.
Intranets that share a portion of their content with customers, suppliers, or other businesses, but not with the general public, are called extranets. As with intranets, the same web browsers and other software are used to access the content.
G. VPN:
This uses the public telephone line to create a virtual private network among users.
Requirements for a Network
Ø Physical (cable) or wireless connections between computers
Ø Proper Network adapter cards
Ø Centralized devices to achieve network connections.
Ø Software that enables resources to be shared with other PCs and controls access to shared resources, known as a network operating system
Ø A common set of communications rules, known as a network protocol
Ø Resources that can be shared, such as printers, disk drives, and CD-ROMs
Types of LAN:
There are two basic types of LANs:
A. Peer to Peer (Work group).
B. Server/Client (Domain)
Peer to Peer
Peer-to-peer networks are more common in small offices or within a single department. On a peer-to-peer network, every computer is equal and can communicate with any other computer on the network to which it has been granted access rights.The advantage of a peer-to-peer network is that we don’t have to dedicate a computer to function as a file server. Instead, every computer can share its resources with any other.Disadvantage of a Work group network is that it has less security and less control because there is no centralization.
Server/Client (Domain)
On a Domain network, every computer has a distinct role, that of either a client or a server. A serveris designed to share its resources among the client computers on the network. To make a server computer we require a Server operating system such as Windows Server 2000 or 2003. Typically, servers are located in secured areas, such as locked closets or server rooms. The rest of the computers on the network function as clients and are used to access resources located on servers. A client system is a standard computer that is running an operating system such as Windows XP. These versions of Windows contain the client software that enables the client computers to access the resources that servers share.A server computer typically has faster processors, more memory, and more storage space than a client because it might have to service hundreds of users at the same time.The main advantage of a Domain network is that it provides higher levels of security and more centralized control over client computers.
