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# Topology

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### Topology

1. 1. What is a Topology?The physical topology of a network refers to the configuration of cables,computers, and other peripherals. Physical topology should not be confused withlogical topology which is the method used to pass information betweenworkstations. Logical topology was discussed in the Protocol chapter.Main Types of Physical TopologiesThe following sections discuss the physical topologies used in networks and otherrelated topics. Linear Bus Star Tree (Expanded Star) Considerations When Choosing a Topology Summary ChartLinear BusA linear bus topology consists of a main run of cable with a terminator at each end(See fig. 1). All nodes (file server, workstations, and peripherals) are connected tothe linear cable. Fig. 1. Linear Bus topologyAdvantages of a Linear Bus Topology Easy to connect a computer or peripheral to a linear bus. Requires less cable length than a star topology.Disadvantages of a Linear Bus Topology Entire network shuts down if there is a break in the main cable. Terminators are required at both ends of the backbone cable.
2. 2. Difficult to identify the problem if the entire network shuts down. Not meant to be used as a stand-alone solution in a large building.StarA star topology is designed with each node (file server, workstations, andperipherals) connected directly to a central network hub, switch, or concentrator(See fig. 2).Data on a star network passes through the hub, switch, or concentrator beforecontinuing to its destination. The hub, switch, or concentrator manages andcontrols all functions of the network. It also acts as a repeater for the data flow.This configuration is common with twisted pair cable; however, it can also be usedwith coaxial cable or fiber optic cable. Fig. 2. Star topologyAdvantages of a Star Topology Easy to install and wire. No disruptions to the network when connecting or removing devices. Easy to detect faults and to remove parts.Disadvantages of a Star Topology Requires more cable length than a linear topology. If the hub, switch, or concentrator fails, nodes attached are disabled. More expensive than linear bus topologies because of the cost of the hubs, etc.
3. 3. Tree or Expanded StarA tree topology combines characteristics of linear bus and star topologies. Itconsists of groups of star-configured workstations connected to a linear busbackbone cable (See fig. 3). Tree topologies allow for the expansion of an existingnetwork, and enable schools to configure a network to meet their needs. Fig. 3. Tree topologyAdvantages of a Tree Topology Point-to-point wiring for individual segments. Supported by several hardware and software venders.Disadvantages of a Tree Topology Overall length of each segment is limited by the type of cabling used. If the backbone line breaks, the entire segment goes down. More difficult to configure and wire than other topologies.5-4-3 RuleA consideration in setting up a tree topology using Ethernet protocol is the 5-4-3rule. One aspect of the Ethernet protocol requires that a signal sent out on thenetwork cable reach every part of the network within a specified length of time.Each concentrator or repeater that a signal goes through adds a small amount of
5. 5.  Moves, adds and changes of devices can affect the network Communication delay is directly proportional to number of nodes in the network Bandwidth is shared on all links between devices More difficult to configure than a Star: node adjunction ⇨ Ring shutdown and reconfigurationMisconceptions "Token Ring is an example of a ring topology." 802.5 (Token Ring) networks do not use a ring topology at layer 1. As explained above, IBM Token Ring (802.5) networks imitatea ring at layer 2 but use a physical star at layer 1. "Rings prevent collisions." The term "ring" only refers to the layout of the cables. It is true that there are no collisions on an IBM Token Ring, but this is because of the layer 2 Media Access Control method, not the physical topology (which again is a star, not a ring.) Token passing, not rings, prevent collisions. "Token passing happens on rings." Token passing is a way of managing access to the cable, implemented at the MAC sublayer of layer 2. Ring topology is the cable layout at layer one. It is possible to do token passing on a bus (802.4) a star (802.5) or a ring (FDDI). Token passing is not restricted to rings.
6. 6. MotivationMotivation is a process that elicits, controls, and sustains certain behaviors. Motivation is a groupphenomenon that affects the nature of an individuals behavior, the strength of the behavior, and thepersistence of the behavior. For instance: An individual has not eaten, he or she feels hungry, and asa response he or she eats and diminishes feelings of hunger. There are many approaches to [1]motivation: physiological, behavioural, cognitive, and social . It is the crucial element in setting andattaining goals—and research shows that subjects can influence their own levels of motivation and [2]self-control . According to various theories, motivation may be rooted in a basic need to minimizephysical pain and maximize pleasure, or it may include specific needs such as eating and resting, or adesired object, goal, state of being, ideal, or it may be attributed to less-apparent reasons suchas altruism, selfishness,morality, or avoiding mortality. Conceptually, motivation is distinct [3]from volition and optimism. Motivation is related to, but distinct from, emotion.Brief historyAt one time, employees were considered just another input into the production of goods and [4]services. But this changed after the Hawthorne Studies. The Hawthorne studies were conductedby Elton Mayo at Hawthorne Plant in the 1920s. The researchers were studying the effect of differentworking environments on productivity. They used lighting as an experimental variable (the effect ofbright lighting and dull lighting). Initially they noticed that employees were working harder but it wasnot because of the lighting. They concluded that productivity increased due to attention that theworkers got from the research team and not because of changes to the experimental variable.Hawthorne studies found that employees are not motivated solely by money but motivation is linked to [5]employee behaviour and their attitudes. The Hawthorne Studies began the human relationsapproach to management, so the needs and motivation of employees became the primary focus ofmanagers.Motivation conceptsIntrinsic and extrinsic motivationMotivational poster
7. 7. Intrinsic motivation refers to motivation that is driven by an interest or enjoyment in the task itself,and exists within the individual rather than relying on any external pressure. Intrinsic motivation is [6]based on taking pleasure in an activity rather than working towards an external reward. Intrinsicmotivation has been studied by social and educational psychologists since the early 1970s. Studentswho are intrinsically motivated are more likely to engage in the task willingly as well as work to [7]improve their skills, which will increase their capabilities. Students are likely to be intrinsicallymotivated if they: attribute their educational results to factors under their own control, also known as autonomy, believe they have the skill that will allow them to be effective agents in reaching desired goals (i.e. the results are not determined by luck), are interested in mastering a topic, rather than just rote-learning to achieve good grades.Extrinsic motivation refers to the performance of an activity in order to attain an outcome, whichthen contradicts intrinsic motivation. It is widely believed that motivation performs two functions. Firstone is often referred to the energetic activation component of the motivation construct. The secondone is directed at a specific behaviour and makes reference to the orientation directional component.Motives can be divided into two types: external and internal. Internal motives are considered as theneeds that every human being experience, while external indicate the presence of specific situations [8]where these needs arise.Social psychological research has indicated that extrinsic rewards can lead to overjustification and asubsequent reduction in intrinsic motivation. In one study demonstrating this effect, children whoexpected to be (and were) rewarded with a ribbon and a gold star for drawing pictures spent less timeplaying with the drawing materials in subsequent observations than children who were assigned to an [9]unexpected reward condition. For those children who received no extrinsic reward, self-determination theory proposes that extrinsic motivation can be internalised by the individual if the taskfits with their values and beliefs and therefore helps to fulfill their basic psychological needs.Push and PullThis model is usually used when discussing motivation within tourism context, so the most attention ingastronomic tourism research should be dedicated to this theory. Pull factors illustrate the choices ofdestinations by tourists, whereas push factors determine the desire to go on holiday. Moreover, pushmotives are connected with internal forces for example need for relaxation or escapism and pullfactors in turn induce a traveller to visit certain location by external forces such as landscape, cultureimage or climate of a destination. Dann also highlights the fact that push factors can be stimulated byexternal and situational aspects of motivation in shape of pull factors. Then again pull factors areissues that can arise from a location itself and therefore ‗push‘ an individual to choose to experienceit. Since, a huge number of theories have been developed over the years in many studies there is nosingle theory that illustrates all motivational aspects of travelling. Many researchers highlighted thatbecause motives may occur at the same time it should not be assumed that only one motive drives anindividual to perform an action as it was presumed in previous studies. On the other hand, sincepeople are not able to satisfy all their needs at once they usually seek to satisfy some or a few ofthem.Self-controlThe self-control of motivation is increasingly understood as a subset of emotional intelligence; aperson may be highly intelligent according to a more conservative definition (as measured bymany intelligence tests), yet unmotivated to dedicate this intelligence to certain tasks. Yale School of
8. 8. Management professor Victor Vrooms "expectancy theory" provides an account of when people willdecide whether to exert self control to pursue a particular goal.Drives and desires can be described as a deficiency or need that activates behavior that is aimed at agoal or an incentive. These are thought to originate within the individual and may not require externalstimuli to encourage the behavior. Basic drives could be sparked by deficiencies such as hunger,which motivates a person to seek food; whereas more subtle drives might be the desire for praise andapproval, which motivates a person to behave in a manner pleasing to others.By contrast, the role of extrinsic rewards and stimuli can be seen in the example of training animals bygiving them treats when they perform a trick correctly. The treat motivates the animals to perform thetrick consistently, even later when the treat is removed from the process.Motivational theoriesIncentive theoryA reward, tangible or intangible, is presented after the occurrence of an action (i.e. behavior) with theintent to cause the behavior to occur again. This is done by associating positive meaning to thebehavior. Studies show that if the person receives the reward immediately, the effect is greater, anddecreases as duration lengthens. Repetitive action-reward combination can cause the action tobecome habit. Motivation comes from two sources: oneself, and other people. These two sources arecalled intrinsic motivation and extrinsic motivation, respectively.Reinforcers and reinforcement principles of behavior differ from the hypothetical construct of reward.A reinforcer is any stimulus change following a response that increases the future frequency ormagnitude of that response, therefore the cognitive approach is certainly the way forward as in 1973Maslow described it as being the golden pineapple. Positive reinforcement is demonstrated by anincrease in the future frequency or magnitude of a response due to in the past being followedcontingently by a reinforcing stimulus. Negative reinforcement involves stimulus change consisting ofthe removal of an aversive stimulus following a response. Positive reinforcement involves a stimuluschange consisting of the presentation or magnification of an appetitive stimulus following a response.From this perspective, motivation is mediated by environmental events, and the concept ofdistinguishing between intrinsic and extrinsic forces is irrelevant.Applying proper motivational techniques can be much harder than it seems. Steven Kerr notes thatwhen creating a reward system, it can be easy to reward A, while hoping for B, and in the process,reap harmful effects that can jeopardize your goals.Incentive theory in psychology treats motivation and behavior of the individual as they are influencedby beliefs, such as engaging in activities that are expected to be profitable. Incentive theory ispromoted by behavioral psychologists, such as B.F. Skinner and literalized by behaviorists, especiallyby Skinner in his philosophy of Radical behaviorism, to mean that a persons actions alwayshave social ramifications: and if actions are positively received people are more likely to act in thismanner, or if negatively received people are less likely to act in this manner.Incentive theory distinguishes itself from other motivation theories, such as drive theory, in thedirection of the motivation. In incentive theory, stimuli "attract", to use the term above, a persontowards them. As opposed to the body seeking to reestablish homeostasis pushing it towards thestimulus. In terms of behaviorism, incentive theory involves positive reinforcement: the stimulus hasbeen conditioned to make the person happier. For instance, a person knows that eating food,drinking water, or gaining social capital will make them happier. As opposed to in drive theory, whichinvolves negative reinforcement: a stimulus has been associated with the removal of the punishment--
9. 9. the lack of homeostasis in the body. For example, a person has come to know that if they eat whenhungry, it will eliminate that negative feeling of hunger, or if they drink when thirsty, it will eliminatethat negative feeling of thirst.Escape-seeking dichotomy modelEscapism and seeking are major factors influencing decision making. Escapism is a need tobreakaway from a daily life routine whereas seeking is described as the desire to learn, gain someinner benefits through travelling. Both motivations have some interpersonal and personal facets forexample individuals would like to escape from family problems (personal) or from problems with workcolleagues (interpersonal). This model can also be easily adapted with regard to different studies.Drive-reduction theoryThere are a number of drive theories. The Drive Reduction Theory grows out of the concept that wehave certain biological drives, such as hunger. As time passes the strength of the drive increases if itis not satisfied (in this case by eating). Upon satisfying a drive the drives strength is reduced. Thetheory is based on diverse ideas from the theories of Freudto the ideas of feedback control systems,such as a thermostat.Drive theory has some intuitive or folk validity. For instance when preparing food, the drive modelappears to be compatible with sensations of rising hunger as the food is prepared, and, after the foodhas been consumed, a decrease in subjective hunger. There are several problems, however, thatleave the validity of drive reduction open for debate. The first problem is that it does not explain howsecondary reinforcers reduce drive. For example, money satisfies no biological or psychologicalneeds, but a pay check appears to reduce drive through second-order conditioning. Secondly, a drive,such as hunger, is viewed as having a "desire" to eat, making the drive a homuncular being—afeature criticized as simply moving the fundamental problem behind this "small man" and his desires.In addition, it is clear that drive reduction theory cannot be a complete theory of behavior, or a hungryhuman could not prepare a meal without eating the food before he finished cooking it. The ability ofdrive theory to cope with all kinds of behavior, from not satisfying a drive (by adding on other traitssuch as restraint), or adding additional drives for "tasty" food, which combine with drives for "food" inorder to explain cooking render it hard to test.Cognitive dissonance theorySuggested by Leon Festinger, cognitive dissonance occurs when an individual experiences somedegree of discomfort resulting from an inconsistency between two cognitions: their views on the worldaround them, and their own personal feelings and actions. For example, a consumer may seek toreassure himself regarding a purchase, feeling, in retrospect, that another decision may have beenpreferable. His feeling that another purchase would have been preferable is inconsistent with hisaction of purchasing the item. The difference between his feelings and beliefs causes dissonance, sohe seeks to reassure himself.While not a theory of motivation, per se, the theory of cognitive dissonance proposes that people havea motivational drive to reduce dissonance. The cognitive miser perspective makes people want tojustify things in a simple way in order to reduce the effort they put into cognition. They do this bychanging their attitudes, beliefs, or actions, rather than facing the inconsistencies, becausedissonance is a mental strain. Dissonance is also reduced by justifying, blaming, and denying. It isone of the most influential and extensively studied theories in social psychology.Need theories
10. 10. Motivation, as defined by Pritchard and Ashwood, is the process used to allocate energy to maximize [10]the satisfaction of needs.Need hierarchy theoryThe content theory includes the hierarchy of needs from Abraham Maslow and the two- factor theoryfrom Herzberg. Maslows theory is one of the most widely discussed theories of motivation.The American motivation psychologist Abraham H. Maslow developed the Hierarchy of needsconsistent of five hierarchic classes. It shows the complexity of human requirements. According tohim, people are motivated by unsatisfied needs. The lower level needs such as Physiological andSafety needs will have to be satisfied before higher level needs are to be addressed. We can relateMaslows Hierarchy of Needs theory with employee motivation. For example, if a manager is trying tomotivate his employees by satisfying their needs; according to Maslow, he should try to satisfy thelower level needs before he tries to satisfy the upper level needs or the employees will not bemotivated. Also he has to remember that not everyone will be satisfied by the same needs. A goodmanager will try to figure out which levels of needs are active for a certain individual or employee. Thebasic requirements build the first step in his pyramid. If there is any deficit on this level, the wholebehavior of a human will be oriented to satisfy this deficit. Subsequently we do have the second level,which awake a need for security. Basically it is oriented on a future need for security. After securingthose two levels, the motives shift in the social sphere, which form the third stage. Psychologicalrequirements consist in the fourth level, while the top of the hierarchy comprise the self- realization Sotheory can be summarized as follows: Human beings have wants and desires which influence their behavior. Only unsatisfied needs influence behavior, satisfied needs do not. Since needs are many, they are arranged in order of importance, from the basic to the complex. The person advances to the next level of needs only after the lower level need is at least minimally satisfied. The further the progress up the hierarchy, the more individuality, humanness and psychological health a person will show.The needs, listed from basic (lowest-earliest) to most complex (highest-latest) are as follows: Physiology (hunger, thirst, sleep, etc.) Safety/Security/Shelter/Health Belongingness/Love/Friendship Self-esteem/Recognition/Achievement Self actualizationHerzbergs two-factor theoryFrederick Herzbergs two-factor theory, a.k.a. intrinsic/extrinsic motivation, concludes that certainfactors in the workplace result in job satisfaction, but if absent, they dont lead to dissatisfaction but nosatisfaction.The factors that motivate people can change over their lifetime, but "respect for me as aperson" is one of the top motivating factors at any stage of life.He distinguished between: Motivators; (e.g. challenging work, recognition, responsibility) which give positive satisfaction, and
11. 11.  Hygiene factors; (e.g. status, job security, salary and fringe benefits) that do not motivate if present, but, if absent, result in demotivation.The name Hygiene factors is used because, like hygiene, the presence will not make you healthier,but absence can cause health deterioration.The theory is sometimes called the "Motivator-Hygiene Theory" and/or "The Dual Structure Theory."Herzbergs theory has found application in such occupational fields as information systems and instudies of user satisfaction (see Computer user satisfaction).Alderfers ERG theoryAlderfer, expanding on Maslows hierarchy of needs, created the ERG theory. This theory posits thatthere are three groups of core needs — existence, relatedness, and growth, hence the label: ERGtheory. The existence group is concerned with providing our basic material existence requirements.They include the items that Maslow considered to be physiological and safety needs. The secondgroup of needs are those of relatedness- the desire we have for maintaining important interpersonalrelationships. These social and status desires require interaction with others if they are to be satisfied,and they align with Maslows social need and the external component of Maslows esteemclassification. Finally, Alderfer isolates growth needs an intrinsic desire for personal development.These include the intrinsic component from Maslows esteem category and the characteristicsincluded under self-actualization.Self-determination theorySelf-determination theory, developed by Edward Deci and Richard Ryan, focuses on the importanceof intrinsic motivation in driving human behavior. Like Maslows hierarchical theory and others thatbuilt on it, SDT posits a natural tendency toward growth and development. Unlike these othertheories, however, SDT does not include any sort of "autopilot" for achievement, but instead requiresactive encouragement from the environment. The primary factors that encourage motivation anddevelopment are autonomy, competence feedback, and relatedness.Broad theoriesThe latest approach in developing a broad, integrative theory of motivation is Temporal Motivation [11]Theory(TMT) . Introduced in a 2007 Academy of Management Review article, it synthesizes into a [12]single formulation the primary aspects (including time as a fundamental term) of several othermajor motivational theories, including Incentive Theory, Drive Theory, Need Theory, Self-Efficacy andGoal Setting. The original researchers note that, in an effort to keep the theory simple, existingtheories to integrate were selected based on their shared attributes, and that these theories are still ofvalue, as TMT does not contain the same depth of detail as each individual theory. However, it stillsimplifies the field of motivation and allows findings from one theory to be translated into terms ofanother.Achievement Motivation is an integrative perspective based on the premise that performancemotivation results from the way broad components of personality are directed towards performance.As a result, it includes a range of dimensions that are relevant to success at work but which are notconventionally regarded as being part of performance motivation. Especially it integrates formerlyseparated approaches as Need for Achievement with, for example, social motives like dominance.The Achievement Motivation Inventory is based on this theory and assesses three factors (in 17separated scales) relevant to vocational and professional success.Cognitive theoriesGoal-setting theory
12. 12. Goal-setting theory is based on the notion that individuals sometimes have a drive to reach a clearlydefined end state. Often, this end state is a reward in itself. A goals efficiency is affected by threefeatures: proximity, difficulty and specificity. Good goal setting incorporates the SMART criteria, inwhich goals are: specific, measurable, accurate, realistic, and timely. An ideal goal should present asituation where the time between the initiation of behavior and the end state is close. This explainswhy some children are more motivated to learn how to ride a bike than to master algebra. A goalshould be moderate, not too hard or too easy to complete. In both cases, most people are notoptimally motivated, as many want a challenge (which assumes some kind of insecurity of success).At the same time people want to feel that there is a substantial probability that they will succeed.Specificity concerns the description of the goal in their class. The goal should be objectively definedand intelligible for the individual. A classic example of a poorly specified goal is to get the highestpossible grade. Most children have no idea how much effort they need to reach that goal.Models of behavior changeSocial-cognitive models of behavior change include the constructs of motivation and volition.Motivation is seen as a process that leads to the forming of behavioral intentions. Volition is seen as aprocess that leads from intention to actual behavior. In other words, motivation and volition refer togoal setting and goal pursuit, respectively. Both processes require self-regulatory efforts. Several self-regulatory constructs are needed to operate in orchestration to attain goals. An example of such amotivational and volitional construct is perceived self-efficacy. Self-efficacy is supposed to facilitatethe forming of behavioral intentions, the development of action plans, and the initiation of action. Itcan support the translation of intentions into action.Unconscious motivationSome psychologists believe that a significant portion of human behavior is energized and directed byunconscious motives. According to Maslow, "Psychoanalysis has often demonstrated that therelationship between a conscious desire and the ultimate unconscious aim that underlies it need notbe at all direct."Intrinsic motivation and the 16 basic desires theoryStarting from studies involving more than 6,000 people, Professor Steven Reiss has proposed a [13][14]theory that found 16 basic desires that guide nearly all human behavior. The 16 basic desiresthat motivate our actions and define our personalities as: Acceptance, the need for approval Curiosity, the need to learn Eating, the need for food Family, the need to raise children Honor, the need to be loyal to the traditional values of ones clan/ethnic group Idealism, the need for social justice Independence, the need for individuality Order, the need for organized, stable, predictable environments Physical activity, the need for exercise Power, the need for influence of will Romance, the need for sex Saving, the need to collect Social contact, the need for friends (peer relationships) Social status, the need for social standing/importance