Tuesday, May 31, 2011

Use of networks

Use of networks

All networks offer advantages relative to using a standalone computer—that is, a computer that is not connected to other computers and that uses programs and data stored on its local disks. Most importantly, networks enable multiple users to share devices (for example, printers) and data (for example, spreadsheet programs and files), which are collectively known as the network’s resources. Sharing devices saves money. Another advantage to networks is that they allow you to manage, or administer, resources on multiple computers from a central location.

Types of Networks

Computers can be positioned on a network in different ways relative to each other. They can have different levels of control over shared resources.

Peer-to-Peer Networks

The simplest form of a network is a peer-to-peer network. In a peer-to-peer network, every computer can communicate directly with every other computer. By default, no computer on a peer-to-peer network has more authority than another.

The primary advantage to peer-to-peer networks is that they can be simple to configure. However, peer-to-peer networks are not very flexible. As a peer-to-peer network grows larger, adding or changing significant elements of the network may be difficult. Peer-to-peer networks are also not necessarily secure. A common way to share resources on a peer-to-peer network is by modifying the file-sharing controls via the computer’s operating system. The general consensus is that peer-to-peer networks are practical for up to 10 users.

Client/Server Networks

Another way of designing a network is to use a central computer, known as a server, to facilitate communication and resource sharing between other computers on the network, which are known as clients. Clients usually take the form of desktop computers, also known as workstations. A network that uses a server to enable clients to share data, data storage space, and devices is known as a client/server network.

To function as a server, a computer must be running a network operating system (NOS), a special type of software designed to manage data and other resources for a number of clients.

LANs, MANs, and WAN networks

A local area network (LAN) is a network of computers and other devices that is confined to a relatively small space, such as one building or even one office. Small LANs first became popular in the early 1980s. Networks may extend beyond the boundaries of a building. A network that is larger than a LAN and connects clients and servers from multiple buildings—for example, a handful of government offices surrounding a state capitol—is known as a metropolitan area network (MAN).

A network that connects two or more geographically distinct LANs or MANs is called a wide area network (WAN). WANs commonly connect separate offices in the same organization, whether they are across town or across the world from each other. The largest and most varied WAN in the world is the Internet.

Elements Common To All Client/Server Networks

The following list provides a more complete rundown of basic elements common to all client/server networks.

WorkstationNetwork interface card (NIC)
Network operating system (NOS)Host
Connectivity deviceProtocol
Data packetAddressing
Transmission media

How Networks Are Used

The functions provided by a network are usually referred to as network services. Printer sharing, file sharing, Internet access, remote access capabilities, and management services are all critical business functions provided through networks.

File and Print Services

File services refer to the capability of a server to share data files, applications and disk storage space. A server that provides file services is called a file server. Using print services to share printers across a network also saves time and money. A high-capacity printer can cost thousands of dollars, but can handle the printing tasks of an entire department, thereby eliminating the need to buy a desktop printer for each worker.

Communications Services

A network’s communications services allow remote users to connect to the network. (The term remote user refers to a person working on a computer in a different geographical location from the LAN’s server.) Network operating systems such as Windows Server 2003 and NetWare include built-in communications services. These services enable users to dial into an access server, or the server running these communications services, log on to the network and take advantage of any network features, just as if they were logged via a workstation on the office LAN. An access server may also be known as a communications server or a remote access server.

Mail Services

Mail services coordinate the storage and transfer of e-mail between users on a network. The computer responsible for mail services is called a mail server.

Internet Services

A web server is a computer installed with the appropriate software to supply Web pages to many different clients upon demand. Supplying Web pages is only one type of Internet service. Other Internet services include file transfer capabilities, Internet addressing schemes, security filters, and a means for directly logging on to other computers on the Internet.

Management Services

Network management services centrally administer management tasks on the network, such as making sure that no more than 20 workstations are using Adobe Photoshop at one time in an organization that purchased a 20-user license for the software. Numerous services fall under the category of network management. Some of the more important ones are listed in the text.

The fundamentals of networking are simple. We started to learn about networking in kindergarten. SHARE! That is the objective. That is the result. Never lose sight of this.