Computer networks consist of multiple computers and other electrical devices linked together. Networks are classified as local area networks (LANs) or wide area networks (WANs). The difference between LANs and WANs is usually determined by the length of the network. Generally, a LAN's distance includes only several hundred yards. LANs reside mostly in offices, work areas, classrooms, one building, or within several buildings. WANs exist over many miles, across several cities, and even around the world. WANs are multifaceted and complex networks. They require many devices that connect different computers using diverse communication services. WAN communication speed, reliability, and connectivity are more challenging to manage than those of a LAN.
HISTORICAL ACHIEVEMENTS IN COMMUNICATION AND TRANSPORTATION
Networks were developed as a communication method between computers at remote sites. They trace their roots back to nineteenth-century communication and transportation historical achievements. In America, people have always strived for faster travel and communication systems, particularly between the East and West Coasts. These systems included technology and experiments of varying complexity. For example, the Pony Express operated between 1860 and 1861. It provided seven-day mail service between St. Joseph, Missouri, and Sacramento, California.
In 1861 the Western Union Telegraph Company replaced the Pony Express and provided a faster, more reliable communication service. Furthermore, the transcontinental railroad was completed at Promontory, Utah, in 1869. These events improved the telegraph industry. The telephone was invented in 1876, and the first transcontinental telephone line was joined at Wendover, Utah, in 1915. This national telephone network provided a foundation for the wide area computer networks that evolved later in the twentieth century.
LANs consist of computers, scanners, printers, and cables, which are privately owned. WANs connect computers, scanners, printers, and other devices that sometimes may be leased or rented from public and private telephone companies or data communication companies. These networks place high demands on security and reliability.
In addition, the communication line or medium that a company uses for its network is either cable or a wireless technology. When a business creates a WAN, it might not manage all the lines. Sometimes a business leases lines from a communication company. These companies are data and voice carriers such as MCI, Sprint, Verizon, Williams Communications, and AT&T. In these cases, the WAN is not entirely owned by the initial business. The business owns the line up to the point where the handoff with the data carrier occurs. Then, the carrier company handles the transfer of data and hands it back to the business's private LAN network at a location many miles away.
The size of a LAN is set by the type of LAN configuration and specifications. For example, a LAN in a building might use an Ethernet technology such as 10Base2, also known as Thin Ethernet. This network technology can have one segment 656 feet (200 meters) in length or five linked segments up to 3,281 feet (1,000 meters) in length. A segment is the length of cable between two computers. For 10Base2, the 10 stands for 10 megabits per second, Base means baseband, and 2 equals 200 meters. Another technology is fiber distributed data interface (FDDI). FDDI networks can be up to 124 miles (200 kilometers) in length; these, however, are mostly used as backbone cables that link several LANs.
Because WANs cover large areas, they consist of network technology that extends farther distances than LANs. They incorporate technologies such as FDDI, DSL (digital subscriber line), satellite, and microwave communications. Also, they require routers, switches, and hubs that amplify and direct signals to other routers, switches, and hubs. They can increase their distances nationally and globally.
Another characteristic of a computer network is speed. Network speeds are measured in bits per second. For example, a byte consists of 8 bits, and one alphabetic character or numeric digit consists of 1 byte. If an average word length is five characters and an average double-spaced page is about 200 words, then a page (counting words and spaces) would consist of about 9,600 bits—((200 words×5 characters)+199 spaces)×8 bits. If a network speed is 9,600 bits per second (bps), then a normal double-spaced page is transmitted every second. If a network speed is 56,000 bits per second (56Kbps), about six pages of information per second would be transmitted.
LANs and WANs, however, are typically faster than 9,600 and 56,000 bps. Many networks are 10, 16, or 100 megabits per second (Mbps). A 100 Mbps network can send 100,000,000 bits in one second—or 10,416 pages per second. Some networks can transmit 2 billion to 8 billion bits per second (gigabits, or Gbps). At 2 Gbps (2,000,000,000/9600), 208,000 pages flash by every second—more than most people read in a lifetime. Network speeds are even reaching terabits per second. One Gbps equals a thousand gigabits—almost unthinkable!
The medium used to carry signals on a network can be conducted or radiated. Electric signals over wire are conducted. Fiber optic, microwave, infrared, and radio waves are examples of radiated media.
Wire can be shielded (STP) or unshielded (UTP) twisted pair or coaxial cable. UTP is cheaper to install than STP or coaxial cable; therefore, it is a popular network choice. STP or coaxial cable, however, should be used if there is electromagnetic interference on the network. Other networks overcome electromagnetic interference using fiber optic lines and wireless media. They are more expensive, however, than UTP wiring.
Twisted pair wires are rated by the American Wire Gauge (AWG) standard. Smaller numbers mean thicker wires. Regular telephone wire is rated a 28—too thin for most LANs. LANs use AWG ratings between 22 and 26. Another characteristic of twisted pair wires are the number of twists per foot. More twists may reduce cross talk and interference. Cross talk is when one line picks up noise or voices from another line during a conversation or data transmission. Usually 2 twists per foot are a minimum, while 4 are preferred.
Furthermore, the Electronic Industries Association (EIA) has another standard for rating wires. The EIA classifies LAN wires for different uses. For example, Category 3 (Cat 3) must contain 3 twists per foot and is commonly used in creating 10 Mbps LANs. Cat 5 is good for 100 Mbps and has sustained speeds up to 2 Gbps. Cat 7 reliably supports speeds up to 600 Mbps.
Baseband versus Broadband
Currently, most LANs use baseband transmission. Baseband means that there is one signal transmission per line. This means the channel or line is full when one device is sending data. It is easier for baseband LANs than for broadband LANs to have high speeds, behave reliably, and operate with low error rates. Also, baseband LANs are easily monitored by network administrators.
Broadband, on the other hand, means that the line can handle several transmission signals at one time. This is accomplished using different frequencies that act as separate channels. This is called frequency division multiplexing. Broadband networks have the capacity to handle more channels than baseband networks, but they are more expensive and intricate. A single cable that transmits many television channels is an example of broadband technology.
Because of the high interest in obtaining Internet services, broadband technology is becoming more affordable and widespread. For example, some cities are implementing a technology called broadband over power lines (PBL). PBL is a computer network providing Internet data service using broadband transmissions over public power lines. These networks operate at speeds of 90 Mbps.
Networks are diverse connections of components that are susceptible to interference, such as unauthorized breaches by attackers. Because of these vulnerabilities, network administrators have ongoing challenges keeping networks secure. Some of the vulnerabilities include eavesdropping, viruses, denial of service (DoS), spoofing, and e-mail bombs. These potential hazards can disrupt and curtail the goals of effective networks. Government networks, financial institutions, educational institutions, and specialty businesses are highly susceptible to attackers. Some of the methods to assure better security are established network firewalls, computer user policies, filter rules, incoming packet inspection mechanisms, and server isolation. While these can be successful, they are not foolproof. Network security planning and implementation is ongoing and constantly improving.
Wireless LANs are becoming more useful in homes, businesses, and schools. They are also known as Wi-Fi networks. Most of these networks use radio waves for their transmission medium, but some use infrared light waves. Radio waves travel free at the speed of 186,000 miles per second. Unlike light waves, radio waves can travel long distances and can penetrate through nonmetallic objects. Radio waves spread out over vast areas. Because of these advantages, wireless LAN and WAN networks are expanding rapidly.
A concern on wireless networks, interoperability results when vendors produce wireless components that do not work together. Efforts to prevent this from happening have been implemented. One example is the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standard. Most wireless vendors have agreed to follow this standard when producing wireless components. Also, the Wireless Ethernet Compatibility Alliance began certifying vendors who produce components that adhere to 802.11 provisions.
Security on Wi-Fi networks is also a major concern. Security protocols for wireless networks are provided in the 802.11i IEEE data communication standard. This standard defines security protocols that prevent the major security issues such as eavesdropping, spoofing, DoS, and others.
Networks have become an operational necessity for just about every business, government entity, school, and household. Burgeoning information demands make it necessary to link computers for efficient data sharing, storage, and communication. E-mail services are becoming a communication staple among computer owners. Additionally, enhanced services such as electronic commerce, graphics, and videoconferencing are causing networks to grow and expand. Properly managed networks increase productivity and assist managers and administrators with communication demands. Consequently, networks are an essential component of the information system plan of every business. Networks provide a crucial advantage for end users.
see also Information Systems ; Videoconferencing
Dennis J. LaBonty
"Networking." Encyclopedia of Business and Finance, 2nd ed.. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/finance/finance-and-accounting-magazines/networking
"Networking." Encyclopedia of Business and Finance, 2nd ed.. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/finance/finance-and-accounting-magazines/networking
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Social networks are social relationships between two or more people (known as nodes) who have developed some kind of tie with each other (Wasserman and Faust 1994). “The social network perspective focuses on relationships among social entities; examples include communications among members of a group, economic transactions between corporations, and trade or treaties among nations” (Wasserman and Faust 1994, p. i). People use social networks to acquire new information, exchange information, find jobs, learn about new opportunities, and exchange new ideas, among other purposes. Individuals can acquire social ties in a number of social settings such as jobs, social organizations, religious organizations, political organizations, sports groups, a group of friends, and so on.
Wasserman and Faust (1994, p. 4) argue that the social network perspective should take into account the following:
- Actors and their actions are viewed as interdependent rather than independent, autonomous units.
- Relational ties (linkages) between actors are channels for transfer or “flow” of resources (either material or nonmaterial).
- Network models focusing on individuals view the network structural environment as providing opportunities for or constraints on individual action.
- Network models conceptualize structure (social, economic, political, and so forth) as lasting patterns of relations among actors.
In general, social networks are seen as providing individuals or larger groups or social entities with positive outcomes as a result of the information and social support the individuals who belong to a specific social network receive. Those who belong to a social network enjoy the advantages of social capital. The concept of social capital (Loury 1977; Bourdieu 1986; Coleman 1988) has been used to account for the advantages that network members accrue as a result of their inclusion.
According to the organizational literature, the position of the actors in a network or the network structure in which those ties are embedded would in most cases dictate the extent to which belonging to a social network can provide individuals with new information and opportunities that can help them perform better in society or facilitate their upward socioeconomic mobility. For example, central actors can influence how information gets distributed to other members in the network, referred as network centrality (Wasserman and Faust 1994). Also, a key actor could control the information that flows between two independent groups, a situation known in the organizational literature as structural holes (Burt 2001). Also, network homogeneity or structural equivalence (if ties are similar), or network heterogeneity (if ties are different), can influence the kinds of advantages or disadvantages network members might experience as a result of their membership in the network (Wasserman and Faust 1994).
Besides the structure and/or the position in the network, tie strength could also dictate the network’s effectiveness. Mark Granovetter, first in his work The Strength of Weak Ties and later on in his book Getting a Job, revolutionized the organizational literature by introducing the concept of the “strength of weak ties” (Granovetter 1973, 1995). He argues that belonging to an open network and having access to weak ties (or acquaintances) can provide individuals with new valuable information that can help them get better jobs. Even though one might not have a strong relationship with those individuals, they are able to share new knowledge and important information that otherwise would not be available in a closed network with mostly strong ties. Those who belong to closed networks with mostly strong ties are considered to be at a disadvantage given the limited amount of information shared by the members of such networks. Studies on racial segregation (Massey and Denton 1993) have suggested that members of closed networks or cliques have less chance to learn about new important information and that the information that flows in those networks tends to be redundant and inefficient.
According to Granovetter (1982), strong ties and closed networks could be advantageous only for those who face risk and high levels of uncertainty. However, studies of entrepreneurial networks among Asian immigrants in the United States have shown that for certain immigrant groups, having access to strong ties in a closed network of highly educated or high status individuals who share high levels of socioeconomic status tend to receive the social support necessary to be successful as new entrepreneurs (Light, Sabagh, Bozorgmehr, and Der-Martirosian 1994).
Also, the distinction between kin and nonkin ties is fundamental to the understanding of how social networks operate (Adams 1967; Fischer 1982). While individuals can pick their neighbors, friends, or coworkers, they cannot pick the members of their kin (Wierzbicki 2004). In addition, kin ties are everlasting, while any other kind of ties can be dropped at any time (Wierzbicki 2004). Kin ties can be extremely important because they can provide assistance in times of crises, while any other kind of tie might not.
Neighbors can also be important ties in social networks depending on the relationship between neighbors. According to Fischer (1982), neighbors tend to be similar in race and socioeconomic status, and the individual has the freedom to develop or avoid strong ties with neighbors. Proximity is the most important factor in ties between neighbors. Such proximity can become important because it allows for social interactions that could be more difficult to achieve with other kinds of ties.
Today, technological advances such as the development of personal computers, Internet access, e-mail, and cell phones has provided advantages and disadvantages to the development of social ties. While individuals can communicate more often through e-mail and share more information, physical contact has become less frequent. People who are far from each other, even on the other side of the planet, can be in touch every day through the Internet, while those who work together next to each other can also communicate through the computer, limiting their physical and social contact.
Organizational and management literature also uses social networks as the basis for the distribution of information, which could lead to the spread of ideas and innovations and the development of new enterprises (Coleman, Katz, and Menzel 1957; Burt 1987).
Several topics have been studied using the social network perspective approach, including occupational mobility (Breiger 1981, 1990), networks of friends in urban cities (Fischer 1982), the world political and economic system (Snyder and Kick 1979), markets (Berkowitz 1988; White 1981), six degrees of separation (Watts 2003), social networks and international migration (Wierzbicki 2004), and the networks of elite Americans and politicians (Domhoff 1998), among many other. Most people around the world are now aware of the power of social networks and how knowing someone or meeting someone could change one’s future. Advances in technology are helping this task, greatly facilitating communication among actors from any part of the world.
SEE ALSO Bureaucracy; Crony Capitalism; Network Analysis; Networks, Communication; Organization Theory; Organizations; Social Capital
Adams, Bert N. 1967. Interaction Theory and the Social Network. Sociometry 30: 64–78.
Berkowitz, S. D. 1988. Markets and Market-Areas: Some Preliminary Formulations. In Social Structures: A Network Approach, eds. B. Wellman and S. D. Berkowitz, 261–303. Cambridge, U.K.: Cambridge University Press.
Bourdieu, P. 1986. The Forms of Capital. In Handbook of Theory and Research for the Sociology of Education, ed. J. G. Richardson, 241–258. New York: Greenwood Press.
Breiger, R. L. 1981. The Social Class Structure of Occupational Mobility. American Journal of Sociology 87 (3): 578–611.
Breiger, R. L., ed. 1990. Social Mobility and Social Structure. Cambridge, U.K.: Cambridge University Press.
Burt, Ronald S. 1987. Social Contagion and Innovation: Cohesion versus Structural Equivalence. American Journal of Sociology 92 (6): 1287–1335.
Burt, Ronald S. 2001. Structural Holes versus Network Closure as Social Capital. In Social Capital: Theory and Research, eds. Nan Lin, Karen S. Cook, and Ronald S. Burt, 31–56. New York: Aldine de Gruyter.
Coleman, James S., E. Katz, and H. Menzel. 1957. The Diffusion of an Innovation among Physicians. Sociometry 20: 253–270.
Coleman, J. S. 1988. Social Capital in the Creation of Human Capital. American Journal of Sociology 94: S95-S120.
Domhoff, G. William. 1998. Who Rules America? Power and Politics in the Year 2000, 3rd ed. Mountain View, CA: Mayfield.
Fischer, Claude S. 1982. To Dwell among Friends: Personal Networks in Town and City. Chicago: University of Chicago Press.
Granovetter, Mark. 1973. The Strength of Weak Ties. American Journal of Sociology 78 (6): 1360–1380.
Granovetter, Mark. 1982. The Strength of Weak Ties: A Network Theory Revisited. In Social Structure and Network Analysis, eds. Peter V. Marsden and Nan Lin, 105–130. London: Sage.
Granovetter, Mark. 1995. Getting a Job: A Study of Contacts and Careers. Chicago: University of Chicago Press.
Light, Ivan, Georges Sabagh, Mehdi Bozorgmehr, and Claudia Der-Martirosian. 1994. Beyond the Ethnic Enclave Economy. Social Problems 41: 65–79.
Loury, G. C. 1977. A Dynamic Theory of Racial Income Differences. In Women, Minorities and Employment Discrimination, eds. P. A. Wallace and A. M. LaMond, 153–186. Lexington, MA: Heath.
Massey, Douglas S., and Nancy A. Denton. 1993. American Apartheid: Segregation and the Making of the Underclass. Cambridge, MA: Harvard University Press.
Snyder, D., and E. Kick. 1979. Structural Position in the World System and Economic Growth 1955–1970: A Multiple-Network Analysis of Transnational Interactions. American Journal of Sociology 84 (5): 1096–1126.
Wasserman, Stanley, and Katherine Faust. 1994. Social Network Analysis: Methods and Applications. Cambridge, U.K., and New York: Cambridge University Press.
Watts, Duncan J. 2003. Six Degrees: The Science of a Connected Age. New York: Norton.
White, H. C. 1981. Where Do Markets Come From? American Journal of Sociology 87: 517–547.
Wierzbicki, Susan. 2004. Beyond the Immigrant Enclave: Network Change and Assimilation. New York: LFB Scholarly Publishing.
Nadia Y. Flores
"Networks." International Encyclopedia of the Social Sciences. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/networks
"Networks." International Encyclopedia of the Social Sciences. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/networks
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Gregarious people tend to have a wide circle of friends; they enjoy social contact, like to be with people, and have a knack for connecting with others and then staying in touch. When they need something they tend spontaneously to think of a person in their circle who might help or might know someone else who could. Similarly, if they hear of something that might interest a friend, they act. They make a quick call…. This type of temperament and way of behavior is as old as humanity. And successful use of contacts hasn't gone unnoticed either. There is a common saying to the effect that "it's not what you know but who you know"—which attempts to highlight the greater importance of social connectedness than that of abstract knowledge. A very popular bestseller by Dale Carnegie, the motivational teacher and author, was his 1936 title How To Make Friends and Influence People. It was probably not the first book attempting to teach what comes naturally to some. Around about the late 1970s and early 1980s, a time when the baby boom generation was moving into the workforce, the term "networking" appeared. Like Carnegie's method, it was intended to emulate gregarious behavior on purpose and with the goal of gaining benefits in business. Networking has always had an ambiguous character. When it is practiced openly, and the net-worker's desire to make useful business contacts is up front and visible, it is a kind of salesmanship. Quite a few people practice networking openly. Recipients of such attention are not offended; it is, in fact, slightly flattering to be considered important enough to be courted. When the contact-work is disguised as seeking social links or friendship, however, networking has a faintly calculating and exploitive connotation which, once it becomes known, will have the opposite effect from the one intended.
A rather benign form of networking is "social networking" that people engage in when they have problems finding a mate. This often takes the form of self-exposure in environments likely to have a fair supply of eligible partners. People start going to church again, take classes, or take up communal hobbies and sports. Very often others also participating in such activities are also seeking company. Interactions enable people to get to know each other and to test the water. Linkages are formed because of mutual attraction. Both business and social networking have been formalized, the latter in such interesting forms as "five-minute dating" services.
Business networking, certainly in its earlier stages of development, was viewed by many as a valuable new discovery, a kind of leverage with small inputs that have large consequences. But networking is equivalent to marketing a corporate identity, to "institutional advertising," in that nothing specific is being sold except the net-worker's existence—and this to one person at a time. Networking requires concentrated attention, record keeping, and the cultivation of the network—hence it costs time and money. If the networker, realizing the high costs, narrows the field of contacts to individuals deemed more likely to be helpful in the future, networking loses one of its benefits, namely the discovery of unexpected and serendipitous helpers. The more narrowing is introduced, the more networking comes to resemble traditional forms of prospecting, selling, or simply acting in an entrepreneurial manner.
Networking has three basic components: 1) making contacts deliberately; 2) recording contacts made; and 3) cultivating the network. Making contacts means willingness to engage people in conversations (e.g., on airplanes, at parties, at concerts) and to expose oneself to others by visiting events, particularly those likely to yield good links. Showing interest in others, paying attention to them, and engaging in give-and-take are, of course, vital. Business conferences and expositions are a good venue for meeting potentially helpful people in a business context; the active networker will "work the booths" and get to know lots of people. Keeping records is central because relatively brief contacts will fade from the mind, but notes in a database will bring back the memories. The activity requires time and effort. Calling cards must be keyed in or annotated on the back. The use of keywords for contact retrieval is helpful. Cultivating contacts means to renew them from time to time. The more is known about the contact the easier it is to do this. The networker can send contacts clippings that may interest them or call them with some news of interest and thus maintain the linkage. Children's or the contact's birthdays afford opportunities. And so on. The key point regarding cultivation is that networking is a two-way process between any two nodes. The networker must strive to be of help to the contact in order to merit help, down the ways, if it should ever be needed. A natural part of doing this right is to observe the usual courtesies: people should neither be neglected nor smothered and badgered.
Networking in the Internet
Age Not surprisingly, the greatest network of them all, the Internet, has been harnessed to the service of networking, both social and business. In the business networking category, for example, networking clubs have made an appearance. Among them are ItsNotWhatYouKnow (INWYK), LinkedIn, Ryze, and ZeroDegrees. According to Catherine Seda, writing in Enterpreneur, "It's simple to join, and most clubs are free or have a free level of access. Complete the registration form, invite your colleagues to join, and get on each other's 'connections' lists. The bigger your network, the greater your referral opportunities are, because members click on your contacts to see who you know."
Concerning networking in general, the last word on the subject ultimately belongs to George Ball, once Undersecretary of State in the Kennedy and Johnson Administrations. Ball famously said: "Nothing propinques like propinquity."
Horowitz, Alan S. "Social Software: Corporate and Web-based networking software helps people make critical business connections." Computerworld. 19 September 2005.
Kiehne, Thomas P. "Social Networking Systems: History, Critique, and Knowledge Management Potentials." University of Texas at Austin. 29 April 2004.
Lemaire, Barbara C. "52 Tips for Networking Success." New Mexico Business Journal. March 2006.
"Networking." Chartered Management Institute: Checklists: Marketing Strategy. October 2005.
"No Business in Social Networking." eWeek. 4 May 2004.
Pierce, Sarah. "Meet market." Entrepreneur. August 2005.
Seda, Catherine. "The Meet Market: Looking for new business leads? Networking clubs on the web make it easy." Entrepreneur. August 2004.
Shewmake, Brad. "Secrets of Successful Networking." InfoWorld. 3 July 2000.
Wright, Rob. "Before You Make That Next Hire …—Firm finds advisers in unlikely places." VARbusiness. 21 February 2005.
"Networking." Encyclopedia of Small Business. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/entrepreneurs/encyclopedias-almanacs-transcripts-and-maps/networking
"Networking." Encyclopedia of Small Business. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/entrepreneurs/encyclopedias-almanacs-transcripts-and-maps/networking
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In its simplest form, networking takes place between two devices that are directly connected. However, it is often impractical for devices to be directly connected, such as when devices are far apart or when more than two devices want to communicate. The solution is to attach each device to a communication network. Communication networks can be categorized on the basis of architecture and techniques to transfer data:
- broadcast networks, where a transmission from any device is broadcast and received by all other stations;
- circuit-switched networks, where a dedicated connection is established between devices on a network across switching nodes within the network;
- packet-switched networks, where data are sent in smaller units, called "packets," from node to node within a network from source to destination.
The basic configuration, or topology , of a network is the geometric representation of all the links and nodes of a network. A link is the physical communication path that transfers data from one device to another. A node is a network-addressable device. There are five basic topologies: mesh, star, tree, bus, and ring. In a mesh topology, every node has a dedicated point-to-point link to every other node, which requires n (n 1)/2 links to connect n nodes. For example, a network with 5 nodes would need 10 links to connect the nodes. In a star topology, each node has a dedicated point-to-point link to a central hub. If one node wants to send data to another, it sends to the hub, which then relays the data to the destination node. A tree topology occurs when multiple star topologies are connected together such that not every node is directly connected to a central hub. In a bus topology, one long cable connects all nodes in the network; in a ring topology, each node has a dedicated point-to-point connection to the nodes on either side in a physical ring such that a signal from a source travels around the ring to the destination and back to the source.
Network devices use signals in the form of electromagnetic energy to represent data. Electromagnetic energy, a combination of electrical and magnetic fields vibrating in relation to each other, includes electrical current, radio waves, and visible light. Unguided, or wireless, media transport electromagnetic waves without using a physical conductor to guide the wave. Instead, signals are broadcast through media, such as air or water, and are thus available to any device capable of receiving them. Guided, or wired, communications direct electromagnetic waves within the physical limitations of a conductor, which may be metallic wire, a hollow tube waveguide, or optical fiber.
Optical fiber uses light as a transmission medium. Light is electromagnetic energy at a specific range of frequencies (430 to 750 terahertz) whose speed depends on the density of the medium through which it is traveling. Theoretically, rays of light injected into strands of pure glass at specific angles will experience total internal reflection, meaning that no loss of energy occurs when light travels down the strand. In practice, some attenuation (loss of energy) and dispersion (mixing of frequencies) does occur because of impure glass and injected light signals at multiple frequencies; however, the range of frequencies, and thus data rates, that can be supported is dramatically higher than is possible with copper cables.
Copper cabling that accepts and transports signals in the form of electrical current comes in four different types:
- unshielded, which is used most commonly in telephone systems;
- twisted pair, which consists of two copper conductors surrounded by an insulating material and wrapped around each other to reduce significantly the impact of noise;
- shielded twisted pair, which has a metal foil encasing each twisted pair;
- coaxial cable, which carries signals of higher-frequency ranges because of its different construction (a central core conductor enclosed in an insulating sheath that is encased in an outer foil, or braid, that is protected by a plastic cover).
Types of Transmission
Asynchronous Transfer Mode (ATM) is a packet-switched technology where all the packets are the same size, referred to as "cells." Asynchronous means that the cells are independent of each other with potentially different gaps between them. The fixed cell size of 53 bytes allows ATM to have traffic characteristics such as increased switching speed and predictably decreased delay/cell loss, which is preferable for the convergence of real-time voice and video with data.
Other important networking techniques include Ethernet and frame relay. Ethernet is a standard for network devices communicating over a bus topology . Any device wishing to transmit will listen to the bus to determine whether the bus is clear; if the bus is clear, transmission can commence. If a collision between signals from different devices occurs, transmission stops and the process is repeated. Frame relay is a packet-switching protocol with no error correction that is appropriate for fiber optic links with their corresponding low error rates.
A local area network (LAN) is usually privately owned and connects nodes within a single office or building designed to share hardware, such as a printer; software, such as an application program; or data. A wide area network (WAN) provides long-distance transmission over large geographic areas that may constitute a nation, a continent, or even the whole world. A WAN that is wholly owned by a single company is referred to as an "enterprise network," but WANs may buy or lease network capacity from other companies. A metropolitan area network (MAN) is designed to extend over an entire campus or city. A MAN may be a single network, as with cable television, or a series of interconnected LANs.
Two other concepts that are relevant are the Internet and intranets. The Transmission Control Protocol/Internetworking Protocol (TCP/IP) is a set of protocols (or protocol suite) that defines how all transmissions are exchanged across the Internet. The Internet itself is a network of networks connected with the TCP/IP protocol suite connecting more than 200 million devices worldwide in virtually all populated countries. Conversely, an intranet is an organizational network of private addresses not directly accessible from the Internet.
see also Internet; Intranet; Telecommunications; World Wide Web.
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Forouzan, Behrouz. Introduction to Data Communications and Network, 2nd ed. New York: McGraw-Hill, 2000.
Halsall, Fred. Data Communications, Computer Networks and Open Systems, 4th ed. New York: Addison-Wesley, 1996.
Stallings, William. Data and Computer Communications, 6th ed. New York: Macmillan, 2000.
"Networks." Computer Sciences. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/computing/news-wires-white-papers-and-books/networks
"Networks." Computer Sciences. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/computing/news-wires-white-papers-and-books/networks
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A system of communication praised by many in the New Age movement as the best means of organizing people horizontally around common concerns (rather than veritically around leadership structures) and of data sharing. Networking of one kind or another has been practiced for many decades by means of directories, yearbooks, encyclopedias, specialized magazines, and groups, but with the development of modern computer resources, the facilities for accumulating, storing, and disseminating data on a wide scale have been greatly enhanced and accelerated. R. Buckminster Fuller observed,
"The new human networks emergence represents the natural evolutionary expansion into the just completed, thirty-years-inits-building, world-embracing, physical communications network. The new reorienting of human 'networking' constitutes the heart and mind pumped flow of life and intellect into the world arteries."
The concept of rapid access to topical information has special value in relation to New Age beliefs and practices, since so many groups and centers flourish for a while, then change name or address or disappear, sometimes giving rise to splinter movements. Many networking guides are presented in magazine format for distribution at occult and holistic health shops. Some have related publications in different countries through international networking. Many such publications have diaries of forthcoming events, exhibitions, and lectures. Other networking publications appear in a more traditional directory format, regularly updated.
Networking makes it possible to accumulate and disseminate New Age information in a variety of formats and at local, state, or city levels. Typical networking publications in magazine and/or tabloid newspaper format include Common Ground (San Francisco), PhenomeNews (Detroit), Whole Life (New York), and Whole Life Times (Los Angeles). Such publications tend to have a relatively short life, though these mentioned have lasted for more than a decade.
The Whole Life World Fair Expo, organized annually by the Whole Life Times, publishes a catalog that includes networking information on related events, individuals, and publications. The comparable British annual Festival for Mind-Body-Spirit has a special networking feature, inviting the public to "play the Networking Game," i.e., join a network to exchange information with other people, to keep track of meetings and contacts, and to benefit from the use of computers for exchange of information.
The Networking Game charges a small fee and provides guidance notes, a personal networking diary, a networking badge, personal address labels, and information on contacts in one's local area, as well as information on such facilities as Net Workshops, Playshops, a Networking Market for goods and services, and a computer conferencing network for "screen-to-screen" meetings. The Networking Game may be contacted c/o Sabine Kurjo, 21A Goldhurst Terrace, London, NW6 3HD, England.
Lipnack, Jessica, and Jeffrey Stamps. The Networking Book: People Connecting with People. New York: Methuen; London: Routledge & Kegan Paul, 1986.
"Networking." Encyclopedia of Occultism and Parapsychology. . Encyclopedia.com. (April 21, 2018). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/networking
"Networking." Encyclopedia of Occultism and Parapsychology. . Retrieved April 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/networking