Networks have become an integral part of most lives in the modern world of the 21st century. There are several types of networks used for communications and information sharing including local area, metropolitan area, and wide area networks. Every network is linked through communications channels that may be physical channels (e.g., copper or fiber optic cables) or wireless channels (i.e., radio waves). In addition, networks can be structured in a number of different ways through various architectures that determine how the various components interact and cooperate. Networks have many applications for 21st century businesses. General applications of networking include transmitting and receiving messages or documents electronically, data communications, providing an infrastructure for holding virtual meetings with participants who are geographically dispersed, and electronic commerce.
Networks have become an integral part of most lives in the modern world of the 21st century. For example, e-mail has become the standard mode of communication in many situations, and we send not only messages but documents, pictures, and audio/visual clips across the street and around the world with ease. In addition, many of us count on the Internet to enable us to compare and purchase goods and services rather than going to a physical storefront. Increasingly, even our banking is done online. We not only use networking capabilities at home and at work, but also take our laptops and smartphones with us on vacation, feeling adrift at the thought of not being able to keep in touch almost instantaneously. However, networks have other applications as well. In the workplace, networks enable employees to coordinate their activities and to share data, information, and documents in an effort to increase the efficiency and effectiveness of the organization. This ability to share data and information quickly and accurately is essential to the success of many businesses. Particularly as increasing numbers of businesses become active in the global marketplace, networks are becoming integral to the way that many of us accomplish work.
Types of Networks
In general, networks are sets of computers that are electronically linked together. Communications networks are sets of locations (or nodes) with concomitant hardware, software, and information that are linked together to form a system that transmits and receives information. There are several types of networks used for communications and information sharing. Local area networks link multiple local computers to each other and various peripheral devices. Metropolitan area networks link computers over citywide distances at higher speeds than local area networks. Wide area networks link multiple computers that are widely dispersed and use high speed, long distance communications networks or satellites to transmit and receive data.
- Local Area Networks A local area network consists of multiple desktop computers located near each other that linked into a network. These networks are used to connect computers in an office or series of offices, and span distances from a few hundred feet to a few miles. A local area network allows the users to share files and peripheral devices such as printers, fax machines, or storage devices. The computers linked into the network are also referred to as workstations, clients, or nodes. They are connected to a server -- a host computer for the network that provides services to the clients. The server typically has more storage capacity and can process at higher speeds than the client computers. Cloud computing allows comapnies to use space on an external server, maintained by a provider, for both file storage and to deliver applications (Yang & Jia, 2013).
- Metropolitan Area Networks Metropolitan area networks transmit data and information citywide (up to 30 miles) and at greater speeds than a local area network. These networks are optimized for both voice and data transmissions and can, therefore, carry more forms of data than can be carried over local area networks, including voice, data, image, and video data. Metropolitan area networks typically operate over a city-wide network of fiber optic cables. These networks enable the metropolitan area network to provide high quality multimedia transmissions at higher speeds than is possible over local area networks.
- Wide Area Networks Wide area networks comprise multiple computers that are widely dispersed and that are linked into a network. These networks typically use high speed, long distance communications networks or satellites to connect the computers within the network. Wide area networks can be used for a variety of applications, particularly when the client computers that need to be networked are at a distance from each other. For example, a retail chain may use a wide area network to connect its stores across the country or across the world, allowing them to share inventory and sales data and to send e-mail messages to each other. These networks can also be used to connect computerized cash registers which can be used to collect and transmit sales data at each location and transmit them to the company's corporate headquarters as part of the closing procedure each day.
Wide area networks use services provided by a common carrier -- a company that provides public communications transmission services. The speed at which the data are transmitted over the network (referred to as bandwidth or data transfer rate) is determined by the bandwidth. The higher the bandwidth of a transmission, the more quickly data can be transferred within the network. Bandwidth is expressed in thousands of bits of information per second (kbps), millions of bits per second (mbps), or billions of bits per second (gbps). On a more practical level, a typical page of typed correspondence contains approximately 275 words, which translates to 2000 bytes or 16,000 bits of information. Transferring this amount of data over a 56 kbps modem takes approximately .28 second; transferring the same page over a high speed network transmitting at 1.544 mbps, however, only takes approximately .01 second. Although this may seem to be a small difference, business documents are frequently significantly longer than one page. So, for example, transmission of a 600 page document at 2400 Bps would take nearly two hours, at 56,000 Bps would take only 5 minutes, and at 1.544 mbps would take only 10.8 seconds. Similarly, higher bandwidths are necessary to transmit video transmissions which are made up of a succession of images. Wide area networks sometimes transmit over a T-carrier, a very high speed channel that connects lower speed networks or computers at different sites or over fiber optic cables that allow even faster data transmission.
No matter the type, networks are linked through communications channels (also referred to as network media). These channels may be physical channels (e.g., copper or fiber optic cables)...
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