Windows environment Essay Example for Free

Windows purlieu EssayIf you get these 10 settings right, and youll go a long way toward making your Windows environment more secure. Each of these falls under the Computer ConfigurationWindows SettingSecurity Settings leaf. Rename the Local Administrator Account If the bad guy doesnt crawl in the name of your Administrator aim, hell lose a much harder time hacking it. Disable the Guest Account One of the worst things you can do is to change this account. It grants a fair amount of access on a Windows computer and has no password. Enough said Disable LM and NTLM v1 The LM (LAN Manager) and NTLMv1 authentication protocols have vulnerabilities. Force the use of NTLMv2 and Kerberos. By default, most Windows systems will accept all four protocols. Unless you have in reality old, unpatched systems (that is, more than 10 years old), theres rarely a reason to use the older protocols. Disable LM hash storage LM password hashes are easily convertible to their plaintext password equi valents.Dont allow Windows to line them on disk, where a hacker hash dump beast would find them. Minimum password length Your minimum password size should be 12 characters or more. Dont bellyache if you only have 8-character passwords (the most common size I see). Windows passwords arent even close to secure until they are 12 characters long and really you want 15 characters to be truly secure. Fifteen is a magic number in the Windows authentication world. Get there, and it closes all sorts of backdoors. Anything else is accepting unnecessary risk. maximum password age Most passwords should not be used longer than 90 days. But if you go to 15 characters (or longer), one year is actually acceptable. ninefold public and private studies have proven that passwords of 12 characters or longer are relatively secure against password cracking to about that length of time. typesetters case logs Enable your event logs for success and failure.As Ive covered in this column many times, the vast majority of computer crime victims might have detect the crime had they had their logs on and been looking. Disable anonymous SID enumeration SIDs (Security Identifiers) are numbers assigned to each user, group, and other security subject in Windows or Active Directory. In early OS versions, non-authenticated users couldquery these numbers to identify important users (such as Administrators) and groups, a fact hackers loved to exploit. Dont let the anonymous account reside in the everyone group Both of these settings, when set incorrectly, allow an anonymous (or null) hacker far more access on a system than should be given.These have been disabled by default since 2000, and you should make sure they stay that way. Enable User Account Control Lastly, since Windows Vista, UAC has been the No. 1 protection tool for people browsing the Web. I find that many clients turn it off due to old information about application compatibility problems. Most of those problems have at peace(p) away, and many of the remaining ones can be solved with Microsofts free application compatibility troubleshooting utility. If you disable UAC, youre far closer to Windows NT security than you are a modern operating(a) system.

Phoenix Jackson and the Modern Day Woman Essay Example for Free

capital of Arizona capital of Mississippi and the Modern Day Woman shewA phoenix is a mythical bird of great beauty fabled to live 500 or 600 years in the Arabian wilderness, to blaze up itself on a funeral pyre, and to rise from its ashes in the freshness of youth and live through another cycle of years often an emblem of immortality or of born-again idealism or hope a person or affaire of peerless beauty or excellence a person or thing that has become renewed or restored after suffering calamity or apparent annihilation A person or thing regarded as unequivocally remarkable in around respect. Eudora Welty, in her character genus Phoenix capital of Mississippi, creates humanitys counterpart of the phoenix firebird from oriental tradition (Wampler 4 June 2013). Although Phoenix capital of Mississippi force out not lay claim to the immortality manifested by consuming fiery rebirths (as does the mythological bird), she possesses a fiery spirit and is consumed by love for her grandchild (Wampler 4 June 2013). Phoenix Jackson is wise, confident, fearless, tenacious, courageous, and has a clear goal in mind, which is to pull back her grandsons medicine despite any obstacle that she may face.Phoenix Jackson can be summed up in one word which is noble. All women should adopt the characteristics of Phoenix Jackson but some of those characteristics are being lost with the evolving society. Phoenix Jackson is an elderly African American woman walking into town on a cold winter morning to get medicine for her sick grandson. whizz aspect of Phoenixs likeness to the mythical phoenix is their transit before they die. The Natchez Trace is an old highway that runs from Nashville, Tennessee, to Natchez, Mississippi (Natchez Trace 27 may 2013).By 1800 it was the busiest in the American South (Natchez Trace 27 May 2013). Phoenix lives a way back off the Old Natchez Trace, which indicates that the journey along with the fact that it is December is difficult for her (A Worn pass n. d. ). The obstacles she faces shows how deeply she cares and sacrifices for her grandson. At the end, when we are told she began on the stairs, going down it indicates that she is faced with a return journey as difficult as the one she has just completed (A Worn Path n. d. ).She is also between 80-100 years old which further magnifies the intensity of her journey and the tragic situation of her grandsons dependence on her. Like many people who have lived to be Ms. Jacksons age, they gain strength from the years of trials and experiences in their lives. Ms. Jackson was unschooled, black and a woman who grew up during the depression and slavery years. This along with her many years on earth have made her cautious, strong willed and driven. Phoenixs carriage is yet another aspect of her likeness to the phoenix.At the beginning of the story, Phoenix is described as having a golden color running underneath her skin, and the two knobs of her cheeks were light by a yell ow burning under the dark (A Worn Path n. d. ). Welty further describes Phoenixs hair as being tied back in a red rag (A Worn Path n. d. ). These images cannot be taken to be a mere coincident as the phoenix from the ancient Egyptian legend is described as having a beautiful red and gold plumage. Furthermore, Phoenixs eyes are said to be blue with age (A Worn Path n. d. ).This description is the first of many that give an indication of her age. The phoenix is a bird that matures to an extreme age before it bursts into flame and is reborn from the ashes. Welty also employs some rather unusual imagery, in which she describes Phoenixs skin as having a pattern all its own of numberless branching wrinkles as though a self-coloured little tree stood in the middle of her forehead (A Worn Path n. d. ). All of these ties back in with the age the phoenix grows to. During the 1940s womens roles and expectations in society were changing rapidly.Previously women had very little say in society a nd were stereotyped to stay plateful, have babies, to be a good home maker and wife. Modern daylight women have it so easy compared to women in the 1940s. Women today have many career opportunities that were not open to women of the 20th century. In fact, the great majority of women were illiterate beca custom it was assumed that they didnt need to read if all the work they would do in life was raise children. Women of the 21st century have access to dozens of labor-saving devices that allow them to do housework in a fraction of the while that it took women in the olden days (Womens Rights).Women today use birth control to plan the size of their families. Centuries ago, it was not unheard of for women to have 11 children, and childbirth was the single highest cause of death for women in their 20s and 30 (Womens Rights). Women in these times live under a justice system that tries to stop domestic violence, whereas women in 1808 were the property of their husbands, who could do wha tever they liked without penalization (Womens Rights). No policeman or judge would ever think a man had done wrong if he had to beat his wife to get her to behave.Modern women control their own finances. Women two hundred years ago were unable to sign for a bank loan without a male accept to co-sign (Womens Rights). They were judged incapable of owning property, even to the point that any property that they brought with them into their marriage or inherited from their father was immediately transferred to the safe keeping of their husbands (Womens Rights). If he then turned it into cash and invested it in a business deal that went bad, the wife had no recourse to recover the money. Women were only given the suffrage in 1920 (Womens Rights).Before that, they had no say whatsoever in the laws that were passed that affected their lives. In a few ways, modern women have a harder time than women of yesteryear. Today some women move so far from home that their social and family networks break down. It appears that women living in the 21st century have it vastly easier than women of the 1940s, although not in every case. Phoenix Jackson was a very rare woman during her time and she is unlike the modern women of today. Not many women today or even back then would do what she did for her grandson.Most women are focused on their careers and would send their husband or nanny to get the medicine for their child. Phoenix Jackson sacrificed a lot because of the love she had for her grandson. Phoenix Jacksons courage and tenacity are illustrated repeatedly as she faces crisis after crisis during her journey a frozen day in December, animals in the thicket, hills, thorny bushes, creeks, barbed-wire fences, a com field maze, superstition, a hunters gun, a tower of steps, her own forgetfulness, and failing physical healthall obstacles to be overcome (Wampler 4 June 2013). And thats what Phoenix Jackson does (Wampler 4 June 2013).

Childcare Essays Effects of Media to Children

Childc atomic number 18 Essays Effects of Media to ChildrenEffects of Media to ChildrenMedia has been a significant part of our daily life, a vehicle for communicating to the usual as well as a source of entertainment. Magazines, TV professionalgrams, radio, billboards, news, internet, cell phones are the forms of smokestack media which are considered to be part of our everyday routine. Traditionally, parents serve as primary social models for electric razorren whereas other models may include siblings, teachers, relatives and other persons who are significant in childrens lives. Over time, however, parents influence as models to their children is on the dec as a direct or indirect result of technological advancement and alterations in household economics. Aside from their busy schedules (which is common in dual-career and single-parent households), families of at present seem to gather around rarely because each member has easy access to his or her own television, telephone, computer, music player, etc.. This set-up would imply that children are more addicted to interact less with their parents and spend more time on their own. Thus, children could turn their attention from their parents to more accessible diversions, such as television watching. Without their parents direct focusing or control, such exposure can become excessive and unguarded. It would not be much of a surprise, if what these children watch did influence their thinking and demeanour. Studies conducted by Weiten Lloyd inform that children in the U.S. spend 2-4 hours on TV watching alone and this habit appears to increase as they get older (Kirsh). Children and the youth are medias darling. Media as perceived by children is full of excitement and wonder, because it brings them to a world of reality as well as make believe. A child development quick-witted T. Berry Brazelton, MD., warns parents that, media is really the biggest competitor for our childrens heart and mind (Steyer) . Furthermore, James P. Steyer an advocate for media organization for children, in his book regards media as the other parent since at present time children spend much of their time with these different forms of media. In view of the fact that our society is media saturated, parents should be aware of the validating and invalidating effect of media to children.Medias positive personal effects are First, its academic realiseing opportunities. Over the past 30 years, shows such as Sesame Street, Teletubbies, Barney, and Blues Clues ready provided academic learning to toddlers and pre-aged children. For older children, programs such as Zoom, Cyberchase, and Zoboomafoo are replete with informative, scientific facts. For pre-teens and teenagers, cable channels such as The Animal Planet, The Discovery Channel, and The study Channel offer a wide range of educational fare(Kirsh). Children that are assailable to educational programs are more likely to adopt to what they are watching , to cite an example children(toddlers) from a non-english speaking country that are expose to shows like Barney are able to learn to speak English although with indecorous grammar. They learn to communicate with the English language and by the time they attend school learning grammar will be easier for them. The same is true with older children, programs shown in the National Geographic Channel, The Animal Planet and Discovery Channel and articles written in their published magazine as well as their websites help them to learn and see what a certain animal looks like, see and explore places that are impossible for human to go to and visit places that are overseas. These educational programs help them to look places and animals as well as further explain theories that are learned in the classroom.The second positive effect of media is pro-social behavior learning. Pro-social behavior refers to any run that benefits another person. Comforting, sharing, and destiny are all examples of pro-social actions (Kirsh). Many develop mentalists, especially those leaning towards the tradition of Social-Cognitive perspective argue that much of the changes in childrens behavior may be accounted for by their observation of others. Learning through imitation or more commonly known as Observational Learning, occurs when a child observes and eventually imitates a models behavior. Programs designed for pro social behavior learning teaches children to practice social behavior such as sharing, helping when they themselves interact socially. They are thought how to properly respond to problems encountered in the outside world like in school or in the community. For example a child who watches how kids share art materials in completing a project in Sesame Street will the same way share his crayons to a classmate when he attend school. To further explain this impression, a study conducted by Mares in 1986 suggest that the viewing of pro social television theme can increase positi ve interactions among youth during play and increase altruism (Kirsh). On the other hand, although pro social programs are intended to teach pro social behavior the age of the viewer should be considered because children of younger age are more adaptable to such teaching than older children.Despite the positive effects presented media has negative effects as well. Childrens familiarity with these media models could lead them to pick up new behaviors that are not modeled by their own parents such as First, body image and eating disorder problems. According to the Anorexia Nervosa and Related Eating Disorder organization (ANRED), more than half of teenage girls are on diets or think they should be (Tomeo). TV programs and magazines that show teenage girls that are thin even though unintentional young girls tend to copy their front-runner character. In their target to get thin they put themselves to diet, at times they force themselves not to eat to get thin. On average, girls begin d ieting at the age of eight, and eighty-one per centum of ten-year-olds fear becoming fat. A national eating disorder treatment center in 2006 reported that sixty-three percent of elementary school teachers are concerned about eating disorders in their classroom. From where do these girls get such a poor self image (Tomeo). Unfortunately, mass media most frequently foster negative affective body images among youth (Kirsh). Apparently, models are not limited to real people super heroes, cartoon or video game characters, even television or movie idols, can also serve as symbolic or media models in this case.The second negative effect of media is the introduction to drug use. Commercials give enthusiasm to young viewers because they are entertaining, but the harm it brings to the young minds of children is often overlooked. The youth being exposed in a world surrounded with media, are therefore exposed to adult aimed advertisements like commercials of cigarettes and liquor. According to a group that studies health issues, in 1999 the hydrogen J. Kaiser Family Foundation concluded that the average child between age eight to 18 spends more than 40 hours using television, radio, billboards and the internet wherein advertising occupies much of the time (Youth-Oriented Advertising). Furthermore, it is a fact according to Gerbner that many of this adult oriented advertisements are purposely designed to be attractive to the youth (Kirsh, p. 337). Take locoweed for instance commercials of cigarette infuse curiosity to the youth in the same way that movies and music videos that contain characters that smoke predispose them to do the same. Moreover, ads contribute to problems such as obesity, alcohol abuse and teen smoking (Youth-Oriented Advertising).To sum up, the discussion revealed that aside from parents and significant people who come in contact with the child, symbolic characters can also be potent models. Taking into consideration the presence of factors that ha ve a pervasive influence on the childs counterfeit behavior, the television can be a powerful agent of socialization. Despite its negative effects, however, TV viewing can also have constructive effects on children. Under proper supervision and if viewing is done in moderation, families, particularly parents can harness, and even maximize this mediums potential as a good source of information and helpful avenue for learning.

Examining The Importanceof Key Performance Indicators Construction Essay

Examining The Importanceof Key slaying Indicators Construction EssayThe Latham wrap up, also kn hold as Constructing the Team was published by Sir Michael Latham in 1994 to highlight the inefficiencies of UK construction industry at that time. The industry was underperforming as a whole, generating low profitability and unable to meet clients satisfaction. Latham Report served as a wake-up c entirely for the nation and underlined the immediate need to reform. Sir John Egan picked up from where Latham left off and published the Egan Report, also known as Rethinking Construction in 1998. Egan Report (1998) identified five key drivers of change which be committed leadership, a focus on the customer, integrated processes and teams, a quality driven agenda and consignment to people. Sir John Egan also challenged the industry to reduce its construction cost and time by 10% annually. Egan Report concluded that, if the UK construction industry is to meet sunrise(prenominal) challenges a nd opportunities, it must transform itself, and KPIs were highlighted as a tool for attaining this (Cooper, 2004). The first set of UK Key Performance Indicators (KPIs) was published in 1999 with three main objectives (Constructing Excellence, 2006)Key Performance Indicators can be rather confusing to those who have little knowledge in business management. It is believed that the benefits of KPIs are yet to be fully exploited by the construction industry ever since the publication of Egan Report. KPIs are not new to the industry but they are either not recognised or unbroken away by the management teams (Parmenter, 2007). Nowadays, the term KPIs has become one of the most over- utilize and little understood terms in business development and management (Ibis, 2010). jibe to KPIs expert David Parmenter, KPIs represent a set of assesss focusing on those aspects of organisational military operation that are the most critical for the current and future success of the organisation (P armenter, 2004). When personad correctly, KPIs are able to tell an organisation what to do to better performance dramatically. However, the organisation can only succeed when the company leaders and staff are all together focusing on KPIs. Each business industry has a different set of KPIs for companies to use to measure their success. In the construction industry, companies use indicators such as the number of preventative incidents in a specified time period, profitability of construction projects or reviewing cost of construction materials against the predetermined compute (Vitez, 2010).Cox et al. (2003) state that KPIs are compilations of data measures used to assess the performance of a construction operation. They also state that KPIs could be the methods management uses to evaluate employee performance of a particular task. These evaluations typically compare the actual and estimated performance in terms of effectiveness, efficiency, and quality in terms of both workmanshi p and product. In mold to measure performance or calculate the effects of any given change on the construction process, one must first determine the confiscate KPIs to focus on to measure its impact (Cox et al., 2003). Performance indicators can be defined by either the quantitative results of a construction process, for example /unit, or by qualitative measures such as worker behaviour on the job. Accurate analysis of construction performance can be only performed afterwards the KPIs are determined and monitored (Cox et al., 2003).Before any Key Performance Indicators are determined, it is vital to identify what the organisations goal is (Visitask, 2010). After the goals are identified, KPIs will act as a measure of feeler towards those goals. Whatever the KPIs may be, they must be critical to the success of the organisation (Reh, 2010). After the KPIs have been defined and the way to measure it has also been determined, a clear target has to be demarcated which should be under standable by everyone in the organisation (Visitask, 2010). The target should also be specific so that every individual are able to work together towards accomplishing it. To carry through a particular target level of Key Performance Indicator for a company, every department along with the company leaders have to work in synergy towards it (Visitask, 2010).In short, KPIs help an organisation define and measure progress toward organisational goals. Once an organisation has analysed its mission, identified all its stakeholders, and defined its goals, it needs a way to measure progress toward those goals and KPIs are those measurements (Reh, 2010). Measuring performance allows an organisation to objectively determine what is working and what is not (Ling and Peh, 2005). There are many ways to use KPIs in the business and industry. According to Constructing Excellence (2006), the main ways that KPIs are used in the construction industry areCIPFA (1996) describes benchmarking as a tool for self improvement. It suggests that organisations are often prompted to use benchmarking when they want to reduce cost, achieve more with the equivalent or fewer resources, prepare for competitive tendering, improve quality of service, or change culture of the organisation. Benchmarking can be used in a host of ways. For example a company can compare its performance internally, by benchmarking processes in one office against the same processes in some other or it can undertake similar work externally by examining how it compares with its direct competitors (Pickrell and Garnett, 1997). When choosing a target for benchmarking, it is stovepipe to benchmark similar organisations in the same industry, in similar marketplaces, of a similar size and if possible, working in a similar locality. Such an approach provides not only more substantive and focused targets for improvement, but also data and more general information about what competitors are achieving (Cooper, 2004). However , sometimes it is necessary to go beyond the sphere of ones own industry to identify the best practice in the business (McGeorge and Palmer, 1997).KPIs are a type of performance measurement tool. It allows management to measure the performance of a company in a certain area such as profitability. KPIs can help a team to work together to achieve a common set of measurable goals, and provide a very quick way of seeing the actual performance of a goal or strategic objective (RapidBI, 2009). According to Constructing Excellence (2006), KPIs can also be used as a marketing tool. For example, Contractors can use KPIs to prove that they have brilliant safety records to promote themselves in front of clients when tendering. Besides, KPIs can help companies to use up decisions quicker when there are accurate and visible measures to back them up (RapidBI, 2009). In the construction industry, KPIs help managers to find weak areas in their operations that can be improved, leading to faster co nstruction completion times and fewer employee safety incidents (Vitez, 2010). Moreover, constructions companies who use KPIs in their operations usually have more flexible operations than their competitors (Vitez, 2010). Although not realised by many people, KPIs actually play a part in providing sustainable construction. There are environmental KPIs that measure impact on the environment, energy use, waste, and impact on biodiversity which are all polar to sustainability.Benchmarking can provide an objective analysis of how successful an organisation is performing and allows a company to identify its position in the market (Ling and Peh, 2005). By benchmarking against best practice in the industry, one can identify potential areas of growth or weaknesses and use lessons learnt to make targeted improvements. In long run, companies who benchmark will be able to deliver clients expectations and increase clients satisfaction. Besides, benchmarking can help to lock an organisation int o continuous performance improvement, and to develop a culture in which it is easier to admit mistakes and make changes (CIPFA, 1996). Pickrell and Garnett (1997) claim that benchmarking can help to reduce overheads and increase profitability of a company. It also enables companies to really understand their business processes. The most important thing of all about benchmarking is that it allows better companies to demonstrate that they are capable of delivering good services and products, thus developing a barrier to the poorer performers in the market. When this happens, poorer performers will strive to improve their performance by means of benchmarking the better ones and consequently the overall performance of the industry is increased as the market gets more competitive.

Mobile Ad Hoc Networks MANET

brisk Ad Hoc cyberspaces MANETAbstr deport liquid Ad Hoc Net puzzle out (MANET) is a wireless(prenominal) net civilize candid of autonomous operation. MANET routing has no refractory base transport and consequently thickenings in the internet atomic cast 18 mobile and ego configuring. A MANET is characterized by multi skim routing so that leaf clients be non connected to layer 2 b bely bathroom announce by layer 3 routing. In MANET e truly customer is a potential dispatchr and the topologies atomic turn 18 dynamic due to thickener mobility. This paper presents a comprehensive champaign of intravenous feeding MANET routing communications communications protocols ADOV (Ad Hoc On submit Distance Vector), DSR (Dynamic Source Routing), OLSR (Optimized wed State Routing) and TORA (Tempor wholey Ordered Routing Algorithm). For experimental purpose six scenarios pick up been considered. These 6 scenarios be generated with 3 unalike profession parameters name ly high resolution video, infirm HTTP and high FTP appoint. This occupation was passed individually on to to apiece champion scenario on 2 diametric node frame-up (20, 100 nodes). Finally, graphical evaluation of distributively protocol was based on their mental licks which atomic number 18 calculated on the basis of performance metrics use which ar determination to pole storage atomic number 18a, Ne cardinalrk load and Throughput.Chapter 1 IntroductionThis chapter demonstrates a brief overview of the project. Now days in our day to day life we chitchat so close to(prenominal) spays around the ball accelerating with respect to engineering science. In this technical world Internet has brought revolution in talk media. Communication is said to the regularity of discipline mass meeting either betwixt two people or amidst two end users (in scathe of computers). Communication is said to be do when a file or a marrow is passed over the forte among two peo ple. Here the usage of internet comes into existence. Internet stand be utilize as sh atomic number 18d medium for info interchange between users around the globe. This information domiciliate be of any subjectShort Message lightFile absents characterizationAudio etcWhen these types of information atomic number 18 passed among internet, it uses either the wired media (for connecting users locally) or wireless media (for connecting locally or globally). When this information substitution is do the softwares buy in that information through the protocols available for the single media to furnish the packet to the finale. This is the process of information exchange. In this paper, similar bestow is experimented over MANET ( fluent Ad Hoc Networks) chapter 2 for information exchange using four polar protocols. This frame-up was do internally over a virtual frame-up of interlocks using OPNET modeller 14.5. So the investigation of protocols is d iodin based on the perfo rmance of from each one protocol. In the scenarios, each protocol is passed with 3 polar types of traffics namely High FTP load, High Resolution Video and Light HTTP Browsing. This thesis concludes the performance of four routing protocols towards through the end.Keywords MANET, AODV, OLSR, TORA, DSR, OPNET Modeler 14.5.1.1 Organisation of ThesisThis thesis gives an overview of how the project is organised with respect to each chapter. The precise send-off chapter is Introduction of the Thesis, which shows a project caprice and the tasks to achieve the goals. Second chapter Literature Survey which contains the studies and work which has been done previously by an an other(prenominal)(prenominal) authors on the cogitate topics with the parameters utilize by them for their work. The scenarios employ for my work are tie in somewhere by overall different results are taken with different parameters used. Again the sorting and the background work of MANETs are explained spare- beat act the comparison of MANET routing protocols. The parameters and scenarios used for my work are explained briefly with the dissembling setup in chapter 3, Implementation. The results of the excuses and experiments performed are explained in chapter 4, performance Evaluation and Design. The results are taken diagrammatically which friends in comparing the results for routing protocols against the performance metrics used to investigate the performance. The graphs are explained briefly in chapter 4. The results ga in that respectd with the help of scenarios in chapter 3 are reason with the future day work on the routing protocols in chapter 5, Conclusion and Future fail. Finally the supported documents for the project which helped in do the color and project start up is kept in Appendix A. And finally chapter 6 shows all the solutions and references used for the thesis to help in achieving all the supported information and work.1.2 Objective of WorkThe main objective of this work is to guinea pig the different routing protocols, which are developed for Mobile Ad hoc entanglements (MANETs), and to compare the different routing protocols by using simulation beak OPNET Modeler 14.5. As a part of the work four major routing protocols OLSR, AODV, DSR and TORA have been selected and carried out the simulations for comparing the performance of these protocols. Three performance metrics delay Network Load and Throughput are used to compare the performance of the routing protocols.Objective 1To get a take up understanding and functioning of different routing protocols for Mobile Ad hoc communicates. This objective could be achieved by reading and understanding the various papers available on routing protocols of Mobile Ad hoc networks.Objective 2To do a literature survey of previous work done on MANET Routing Protocols so that something different and efficient simulation could be introduced. For this objective different articles and papers publishe d has been study thoroughly and analysed from websites, books and all relevant re semens available. By going through literature survey on routing protocols, the desired simulation environment and setup have been introduced with different simulation parameters. Literature Survey is explained in chapter 2.Objective 3Conducting an experiment and collecting the getup entropyThis objective has been achieved by calculating the appropriate networks with the appropriate simulation parameters and running a simulation for different protocols for different performance metrics. After conducting the simulation the output data have been still graphically. The results are shown graphically and explained in the project in chapter 4.Objective 4Analyzing the output data and ending up with summary and the conclusionThe results have been studied and explained in chapter 4. After studying the simulation results conclusion has been made with some future work which muckle be done further. Conclusion of the project and future work is explained in chapter 5.Chapter 2 Literature Survey2.1 IntroductionThis chapter gives a brief introduction about the work done in previous related papers and reports related to this project. In addition, the introduction to the routing protocols and their classification with respect to routing is demonstrated. This chapter is a short review of the previous work done and the additional objectives regarding routing protocols. The four MANET routing protocols are selected to evaluate the performances they are OLSR, AODV, DSR and TORA. The further instruction executions of these protocols are explained later in this thesis (Chapter 3). MANET is an al-Qaida less network which provides the immunity to the nodes to be free to move anywhere in the network (Stefano Basagni, 2004).2.2 Related Work on Routing ProtocolsAs we see from (Mahmoud), analysis of two antiphonal protocols DSR and TORA were done using OPNET Modeller. In their simulation scenario, they used 50 wireless devices in each scenario with constant traffic parameters and protocol specification settings. They have passed FTP traffic of 1000 bytes making it constant throughout the simulation. Evaluation of these protocols was done based on the performance metrics used which are Delay, Data dropped, Throughput and media access delay. Their simulation results shows that DSR performance was better than TORA in terms of throughput as TORA produces less throughput due to additional overhead used for path creation and path maintenance. At the aforesaid(prenominal) time TORA minimizes communication overhead by localization which results in less delay when compared to DSR as on that visor is no such machine in DSR.Similarly, from (Zukarnain, 2009) they have done evaluation of MANET routing protocol AODV in disposition to establish the connection between the nodes since the mobile node can change their network topographic anatomy frequently. So their study was carried on different mobile node movement pattern which are Random Waypoint Mobility Model, Random Walk Mobility Model and Random Direction Mobility Model. In clubhouse to evaluate the performance of the protocol with these node movement patterns, performance metrics used were Routing overhead, Throughput and Packet delivery ratio. They used 2 simulation scenarios where in the set-back scenario comparison was made on different mobility model varying different number of nodes 5, 10, 15, 20, 25 with fixed speed of 15m/s and in other end comparison was made to evaluate the protocol on different mobility models with varying speeds 5, 10, 15, 20 m/s and 50 nodes as constant all through. They reason out that Random waypoint model is best for AODV compared to other mobility models as the protocol produces highest throughput than compared to others.Other related work from (Nyirenda, 2009) gives the similar working of MANET routing protocols AODV, OLSR, DSR and TORA on OPNET 14.5. Their work carrie d out for study the performance of the four protocols by different performance metrics which are Network load, Packet delivery ratio, Packet end-to-end delay and Throughput. The simulation setup which was implemented on 6 different scenarios where the traffic passing on to the network was ranging from start to high network load, nodes changing from 5, 20, 50 and with speed ranging from 10 m/s to 28 m/s. Mobility model used in this was Random waypoint model for mobility pattern. They conclusions included in their work showed that OLSR performed better compared to the other protocols as it has a bad routing overhead and hence it is well suited for bounteous and complex networks. So apart from routing overhead OLSR performed better but with routing overhead DSR is better. alone when in small network AODV is ofttimes better compared to other protocols. So finally, proactive protocols perform well in high capacity connectives whereas reactive protocols perform better in low capacity networks.From a nonher paper (Maltz, 2001), we see that working on demand routing protocols in MANET was done where DSR protocol was compared to other on demand protocols like AODV, TORA and DSDV. modeling setup carried is represented in turn offs belowWith the above simulation setup the protocols were evaluated based on the performance metrics used which was Packet delivery ratio, Routing overhead, course optimality and lower speed of nodes. The conclusions showed that DSR performed well when referred to packet loss rate and routing over head is concerned. Of all careful implementation done with all the above parameters well-tried on the experiment test beds DSR out performed in every case scenario used when compared all the other protocols used in this setup.2.3 Background WorkA network can be said as association of different systems or organizations where sharing the information can be done collectively. Whereas in figure terms it can be simply defined as a group of compute rs connected together logically to share information like printing, faxing, and so forthThe network can be divided into 2 types based on their working behaviour. They areInfrastructure network These networks are used where the topology is said to be limited and in that location is a fixed point like base station ( broadly speaking referred as send offr) to transmit signals and the end points which are connected to base station communicate with each other devices on the network switching from one base station to another. When a node moves out of range within its network, thus it is said to be connected to another base station range where this process is referred as handoff. We can oftentimes see this type of mechanisms in infrastructure and fixed or wired networks.Infrastructure less network These networks are a natural type of networks where in that location are no such fixed nodes or topologies on the network and the end pints or devices on the network are free to communicate with each other devices on the network as each device on the network behave themselves as routers and encourages communication process all over the network. By this we can say that wireless technology is a promising technology that can tolerate the information exchange worldwide. In the last decade we can besides see the constant emergence in the growth wireless technology issues, one of which being mobile devices such as laptops, cell phones, PDAs and so onAd hoc networks are in addition the part of this type of network.Mobile Ad hoc network is a parvenue technology emerged with the hypothesis of wireless networks. These networks are very typical and do not use any fixed infrastructure for communication process. The nodes connected in these networks are wireless links which are mobile in nature and communicate with each other mobile node in the network with radio transmission and topology is said to establish by the medium nodes on the network which are accommodative for com munication process. As there are no fixed infrastructure and limited topology constraints the nodes on the network are free to join and pass along the network and this is possible as the nodes on the network are mobile. Due to this random movement of the nodes in the network the topology of the network changes dynamically. Due to this change protocol must be able to acclimatize with these movements and are also responsible to proceed the routes of the information traveled without disturbing network connectivity.This concept of ad hoc network allows each node on its network to act like router, resulting in the flow of information exchange with multi hop routing. These types of networks are widely used in military and other rescue applications. (Saadawi, 2003)2.4 RoutingRouting is the process of moving the data from one place of the network to another. The one end should be the semen which intends to transfer the data to the term (other end). The concept of routing has been ther e since 1970s but it has caught the move in 1980s. In 1970s networks were artless and today there are large scale networks in existence. To move the data from one array to another at to the lowest degree one router is required in the network. trackr has all the information regarding hosts in the network and it can manipulate the best possible route as well. (Javvin, 2004)Routing takes place at bottom 3 in OSI 7 layer Model. near of the protocols at layer 3 are IP and IS-IS. These protocols carry the data between source and reference along with their addresses in the data packet. Routing involves two basal activities Path Determination and Switching. These two activities are capable to delimit the optical routing path and to transfer the data packets through internetworking. This is called Switching. Switching can still be easy where as determining the reliable path is difficult.Path DeterminationRouting make use of the different routing protocols to determine the best poss ible path to deliver the data. Routing protocols use the metric to calculate which the best possible path to accomplish the task is. The metric used could be path bandwidth, path length, delay etc. to determine the optimal path. To determine the path in the network, routing algorithms maintains the routing tables which are used to store the routing information about the network. travel guidebookrs communicate with each other in order to maintain their routing tables which make communication easier and faster. Routing information can vary according to the routing algorithm used for the process. (Cisco, 2010)Switching obscure from path determination, router shows one to a greater extent activity Packet Switching. Switching simply mover forthing the required data from one interface to the another in order to reach the reference. In this case, the data to be forwarded is packet. The attached interface address is decided by using the goal address present in the packet. Though the nodes know the next hop address, they still need to know how to use it. So for that reason they use routing tables. The routing table throws the packet away when the destination is unknown. But when the destination is known routing table posses all the interface information forming the route to the destination. (2006)The next hop address could be another host or either it could be a router. fit to ISO developed hierarchical terminology, the systems which have the potency to forward the data from the source to the destination are called Intermediate Systems (IS) and the systems which fails to do so are called as End systems (ES). When it is a router it follows the same procedure as this one, and if it is a host it simply forwards the packet. In packet switching, the Layer 3 address of the source and the destination remains the same to authenticate the original sender and the receiver. However the Layer 2 address (MAC) changes from router to router and from router to host which at l ast determines the destination host. (Cisco, 2010)2.5 Ad hoc NetworksAn ad hoc network is a collection of umteen autonomous nodes connected together by radio waves and maintain the connectivity in de exchangeised manner. Wireless ad hoc networks are connected through wireless links so there is no need of any physical medium and hence contend of the medium is eer there such as noise, interference and fading. On ad hoc networks each node functions as a node and a router itself. It simply means there is no need of an additional switch or a router to route the data and the control is given to the nodes themselves. (Yang Li, 2010)2.6 Mobile Ad hoc NetworksA Mobile Ad hoc Network is an autonomous network formed by hundreds or thousands of nodes. These networks dont need any infrastructure as they can act as a node and router itself. They are free to move anywhere in the network and are connected through radio links. The alone limit point with the MANETs is that they can communicate in a particular rage of the radio waves and outside the network they need some additional arrangements to communicate. To overcome this limitation the Intermediate Node or sometimes called as Relays are brought into picture. Intermediate nodes help in forwarding the packets to the destination. In MANET nodes are free to travel anywhere in the network, hence network topology cannot be fixed for such networks and it keeps changing depending on the current location of the nodes. (ANTDS, 2001)The fundamental differences between the wired networks and MANET areAsymmetric connectednesssRedundant LinkInterferenceDynamic regional anatomy2.7 Characteristics of MANETsThere are several MANET routing protocols which should handle the several inherent characteristics of MANETs as follows as mentioned in (Subbarao)(Jain, 2005)Dynamic Topologies Since the MANET is infrastructure less ad hoc networks, the nodes are free to move arbitrarily. The mobility of nodes may be random and so unpredictable. So the links between the nodes may be uni come outional or bidirectional at times.Bandwidth labored, Variable Capacity Wireless Links Wireless links generally are bandwidth constrained. Since there is a lower capacity in wireless links as compared to the wired links, the traffic congestion is typical rather than different.Energy/Power Constrained Operation Energy consumption is spanking in MANETs as these nodes operate typically off power limited sources. Some or all nodes in MANETs rely on batteries.Limited visible Security Wireless networks like MANETs are more vulnerable with the security issues available with them. Issues like eavesdropping, jammer attack, spoofing and denial of aid attacks must be carefully considered.2.8 pack of MANET Routing ProtocolsA mobile ad hoc routing protocol is used to discover new routes and maintain the existing routes between the nodes in the network. MANET (Mobile Ad Hoc Network) is the collecting of mobile nodes which are present in random m anner in the network has the capacity to communicate and exchange information in effect over the network by facilitating the median(a) nodes for their communication. The essential task of a MANET protocol is to create or discover the correct and efficient routes between the nodes so that information can be delivered accurately with respect to time. Route construction should be done with less overhead and marginal bandwidth consumption for effective communication.2.9 Applications of MANETsApplications of MANETs can be used in many critical situations today and are increasing widely. There are many applications of MANETs today and some of them are mentioned here. An ensample application is for search and rescue operations. such kind of operations is characterized by the networks without having an infrastructure present. One of the reasons for this may be because all of the equipment was destroyed or may be the region is too remote. delivery boy must be capable of communicating to use their energy fairly and also they must maintain the security. Carrying the equipments for communication that the rescuers are already using makes the caper easier.The commercial application for MANETs includes computing everywhere which means the mobile devices are free to move anywhere in the network and yet it is possible to be in communication with the devices. The computers are allowed to forward the data to another computer or data networks may be extended far beyond the considered reach. such networks may be more widely available and much easier in use.Another important application of MANETs is detector Networks. Sensor networks are composed of very large number of small sensors which are able to detect number of properties of the area, for example temperature, pressure, toxins, pollutions etc. In this case, the capability of sensor network is much limited. So there is always need to forward data to the central computer and for this purpose they have to rely upon others in order to forward data to the central computer. The sensor networks individually are limited in their computing capabilities but together can be very effective and the key to future country of origin security. But individual sensors because of their limited computing capabilities can prove prone to failure and loss.There are many other applications of MANETs like personal area networking where the communicating nodes may be mobile phones, laptops etc. Also this has a potential in military operations with the nodes of the network as soldiers, tanks and airplanes. Many more areas includes civilian environment to diverse taxi cab networks, conference rooms, boats and ships. (Bluetronix, 2006)2.10 Classification of Routing ProtocolsAccording to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categories tabularize driven (proactive) Routing2.10.1 Proactive (Table-Driven) Routing ProtocolsThese routing protocols are similar to and come as a natural extension o f those for the wired networks. In proactive routing, each node has one or more tables that contain the latest information of the routes to any node in the network. all(prenominal) row has the next hop for reaching a node/subnet and the cost of this route. Various table-driven protocols differ in the way the information about a change in topology is propagated through all nodes in the network. (LinuxOnly)In proactive routing protocol each node maintains the up to date routing information of all nodes in the network. Here each node maintains the routing table and broadcast it when there is a change in network topology. As soon as source needs the route to the destination it can select from the routing table. The routing table is transfer periodically by publicise to all nodes in the network to keep track of the new gist as yet though the topology is not changed. Each nodes has the routing information of all nodes in the network though most of it undesired. Advantages of proactiv e protocols are that the communication experiences a minimal delay and routes are up to date. evil is that the routes are broken as a result of mobility of nodes. (Chang)Following are the examples of table driven protocols GSR and OLSR and some other proactive routing protocols are FSR, HSR, ZHLSR, CGSR and WRP etc.2.10.1.1 OLSR (Optimized Link State Routing)OLSR Protocol is based on traditional link deposit algorithm which supports point to point routing strategy. In this strategy the nodes keeps exchanging the information periodically in order to maintain the network topology within the network. OLSR is an optimization version of link state protocols. That means it keeps flooding the topological changes information to all the hosts crossways the network when happens. OLSR is also proved beneficial for the reason that it minimizes the size of each control message exchanged and also it avoids each node to rebroadcast during the update of the routes. It uses the Multi Point Replay ing (MPR) strategy to do the above task. For MPR strategy each node creates a set of all of its neighbouring nodes, generally called multipoint relays of the node, in the network to transmit the packet once again. Each node in the particular set can receive and process the packet but only(prenominal) cannot retransmit it. To use MRPs, each node has to keep broadcasting periodically to all one hop neighbours using hello messages. Another manner to reduce the overhead is to provide the shortest path. When the time interval is reduced for the control messages transmission, it can prove more reactive to the topological changes (Kuosmanen).The implementation of OLSR protocol basically uses two control messages Hello message and Topology Control (TC). The hello messages are to be sent only one hop away from the host and are used for finding the link state information and hosts neighbours. MPR picker sets are constructed with Hello messages which explain which host in the network has ch osen this host to act as MPR and using the information the host can select its own set of MPRs. The Topology control (TC) messages are to be broadcasted across entire network about the advertised neighbours and it includes at least the MPR selector list. As OLSR is proactive entree and it keeps updating the routing table periodically, the TC messages are also broadcasted periodically and the hosts with MPR selector set can only forward the TC messages.There can also be MID message which is Multiple Interface Declaration message to declare that the announcing hosts can have twofold OLSR interface addresses. And again MID message are broadcasted throughout entire network and only by MPRs.2.10.2 thermolabile (Source Initiated) Routing ProtocolsThese protocols take a lazy approach to routing. They do not maintain or constantly update their route tables with the latest route topology. Reactive routing is also known as on-demand routing. The Reactive Routing Protocols are also called a s Source initiated requisite Driven protocols. They are called so because the routes are discovered only when necessitate by source.Source initiated on demand networks cerates routing only when desired by the source node. When source wants to communicate with destination then it invokes the route baring mechanism to find the path to the destination. The route discovery process is completed once a route is found or all possible are identified. at a time the rout is formed between source and destination it is maintained by a route maintenance procedure until the destination becomes inaccessible or the route is no longer desired. (Chang)These Examples of reactive routing protocols are dynamic Source Routing (DSR), Ad hoc on-demand distance sender routing AODV, ABR, SSA, CBRP, and RDMAR.2.10.2.1 AODV (Ad hoc On Demand Distance Vector)Ad hoc On Demand Distance Vector protocol as the name implies it is an On Demand that is, Reactive Protocol. AODV is capable of both unicast and multi cast routing. It is an on demand algorithm, it means that it builds routes between nodes only as desired by source nodes. It uses the concepts of DSR routing for route discovery and route maintenance and DSDV protocol for the concept of date number. It uses sequence number concept to plug the freshness of routes. The ad hoc on-demand Distance vector algorithm facilitates the self-starting, multi hop and dynamic routing between participating nodes to establish and maintain an ad hoc network. AODV algorithm enables the nodes to find the routes for new destinations as and when they are needed and the nodes are not required to maintain the routes to the destination that are not in the part of active communication. It also enables the nodes in the formation of multicast groups and enables the nodes to respond quickly to link breakages and topological changes in the network thus the operation of AODV is loop free and thus avoids the Balham Ford count to infinity problem.AODV routing pro tocol is a simple and effective routing protocol for Ad hoc networks. It also uses the concept of hop by hope routing and sequence numbers from DSDV protocol.The pursuance are the message types defined by AODV they areRoute invite (RREQ),Route replies (RREP),Route error (RERR) and group hellos (GRPH) this message types are handled by UDP and IP header.The route orison message format contains the following palmSource address the address of the node which originates the route requestSource Sequence number the current sequence number to be used in deciding the route for the source request computer address address the address of the target node for which the route is initialized.Destination Sequence numbers the sequence number received by source for route towards the destination.Broadcast ID The sequence number by which a RREQ route request can be uniquely identified. skip counts the number of the hops to be taken from the source node to reach the destination node that handles the R oute request.The Route Reply message format contains the following fieldsDestination address the address of the destination node for which the route is aboundedDestination sequence number the destination sequence number related to the routeSource address the address of the source node that originates the route requestLifetime the time for which nodes receiving the route respond considers the route to be valid.Hop counts the number of hops to be taken from source to destination.The route error message format contains the following fields out of reach(predicate) destination address The address of the destination that has become unreachable due to link failure. (Arbia, 2008)In AODV the only nodes that take active participation in routing process are the nodes that sit in direct path between source and destination. The nodes which do not lie on active path do not take participate or maintain the routing table, thus AODV minimize the number of control messages sent between two nodes. As long as there is a valid routes between the source and destination for communication, AODV does not play any role and when a new route to a new destination is required and if the route to the destination does not exist only then the source node initialize the route discovery process by broadcasting the RREQ message to find the route to destination. TheMobile Ad Hoc Networks MANETMobile Ad Hoc Networks MANETAbstractMobile Ad Hoc Network (MANET) is a wireless network capable of autonomous operation. MANET routing has no fixed base station and hence nodes in the network are mobile and self configuring. A MANET is characterized by multi hop routing so that nodes are not connected to layer 2 but can communicate through layer 3 routing. In MANET every node is a potential router and the topologies are dynamic due to node mobility. This paper presents a comprehensive study of four MANET routing protocols ADOV (Ad Hoc On demand Distance Vector), DSR (Dynamic Source Routing), OLSR (Optimized Link State Routing) and TORA (Temporally Ordered Routing Algorithm). For experimental purpose six scenarios have been considered. These 6 scenarios are generated with 3 different traffic parameters namely high resolution video, light HTTP and high FTP load. This traffic was passed individually on to each scenario on 2 different node setup (20, 100 nodes). Finally, graphical evaluation of each protocol was based on their performances which are calculated on the basis of performance metrics used which are End to end delay, Network load and Throughput.Chapter 1 IntroductionThis chapter demonstrates a brief overview of the project. Now days in our day to day life we see so many changes around the world accelerating with respect to technology. In this technical world Internet has brought revolution in communication media. Communication is said to the method of information exchange either between two people or between two end users (in terms of computers). Communication is said to be don e when a file or a message is passed over the medium among two people. Here the usage of internet comes into existence. Internet can be used as shared medium for information interchange between users around the globe. This information can be of any typeShort MessageMailFile transfersVideoAudio etcWhen these types of information are passed among internet, it uses either the wired media (for connecting users locally) or wireless media (for connecting locally or globally). When this information exchange is done the packets carry that information through the protocols available for the respective media to deliver the packet to the destination. This is the process of information exchange. In this paper, similar work is experimented over MANET (Mobile Ad Hoc Networks) chapter 2 for information exchange using four different protocols. This setup was done internally over a virtual setup of networks using OPNET modeller 14.5. So the investigation of protocols is done based on the performance of each protocol. In the scenarios, each protocol is passed with 3 different types of traffics namely High FTP load, High Resolution Video and Light HTTP Browsing. This thesis concludes the performance of four routing protocols towards through the end.Keywords MANET, AODV, OLSR, TORA, DSR, OPNET Modeler 14.5.1.1 Organisation of ThesisThis thesis gives an overview of how the project is organised with respect to each chapter. The very first chapter is Introduction of the Thesis, which shows a project idea and the tasks to achieve the goals. Second chapter Literature Survey which contains the studies and work which has been done previously by other authors on the related topics with the parameters used by them for their work. The scenarios used for my work are related somewhere by overall different results are taken with different parameters used. Again the classification and the background work of MANETs are explained following the comparison of MANET routing protocols. The parameter s and scenarios used for my work are explained briefly with the simulation setup in chapter 3, Implementation. The results of the simulations and experiments performed are explained in chapter 4, Performance Evaluation and Design. The results are taken graphically which helps in comparing the results for routing protocols against the performance metrics used to investigate the performance. The graphs are explained briefly in chapter 4. The results gathered with the help of scenarios in chapter 3 are concluded with the future work on the routing protocols in chapter 5, Conclusion and Future Work. Finally the supported documents for the project which helped in making the simulation and project start up is kept in Appendix A. And finally chapter 6 shows all the sources and references used for the thesis to help in achieving all the supported information and work.1.2 Objective of WorkThe main objective of this work is to study the different routing protocols, which are developed for Mob ile Ad hoc networks (MANETs), and to compare the different routing protocols by using simulation tool OPNET Modeler 14.5. As a part of the work four major routing protocols OLSR, AODV, DSR and TORA have been selected and carried out the simulations for comparing the performance of these protocols. Three performance metrics delay Network Load and Throughput are used to compare the performance of the routing protocols.Objective 1To get a clear understanding and functioning of different routing protocols for Mobile Ad hoc networks. This objective could be achieved by reading and understanding the various papers available on routing protocols of Mobile Ad hoc networks.Objective 2To do a literature survey of previous work done on MANET Routing Protocols so that something different and efficient simulation could be introduced. For this objective different articles and papers published has been studied thoroughly and analysed from websites, books and all relevant resources available. By go ing through literature survey on routing protocols, the desired simulation environment and setup have been introduced with different simulation parameters. Literature Survey is explained in chapter 2.Objective 3Conducting an experiment and collecting the output dataThis objective has been achieved by designing the appropriate networks with the appropriate simulation parameters and running a simulation for different protocols for different performance metrics. After conducting the simulation the output data have been collected graphically. The results are shown graphically and explained in the project in chapter 4.Objective 4Analyzing the output data and ending up with summary and the conclusionThe results have been studied and explained in chapter 4. After studying the simulation results conclusion has been made with some future work which can be done further. Conclusion of the project and future work is explained in chapter 5.Chapter 2 Literature Survey2.1 IntroductionThis chapter gives a brief introduction about the work done in previous related papers and reports related to this project. In addition, the introduction to the routing protocols and their classification with respect to routing is demonstrated. This chapter is a short review of the previous work done and the additional objectives regarding routing protocols. The four MANET routing protocols are selected to evaluate the performances they are OLSR, AODV, DSR and TORA. The further implementations of these protocols are explained later in this thesis (Chapter 3). MANET is an infrastructure less network which provides the freedom to the nodes to be free to move anywhere in the network (Stefano Basagni, 2004).2.2 Related Work on Routing ProtocolsAs we see from (Mahmoud), analysis of two reactive protocols DSR and TORA were done using OPNET Modeller. In their simulation scenario, they used 50 wireless devices in each scenario with constant traffic parameters and protocol specification settings. They ha ve passed FTP traffic of 1000 bytes making it constant throughout the simulation. Evaluation of these protocols was done based on the performance metrics used which are Delay, Data dropped, Throughput and media access delay. Their simulation results shows that DSR performance was better than TORA in terms of throughput as TORA produces less throughput due to additional overhead used for path creation and path maintenance. At the same time TORA minimizes communication overhead by localization which results in less delay when compared to DSR as there is no such mechanism in DSR.Similarly, from (Zukarnain, 2009) they have done evaluation of MANET routing protocol AODV in order to establish the connection between the nodes since the mobile node can change their topology frequently. So their study was carried on different mobile node movement pattern which are Random Waypoint Mobility Model, Random Walk Mobility Model and Random Direction Mobility Model. In order to evaluate the performa nce of the protocol with these node movement patterns, performance metrics used were Routing overhead, Throughput and Packet delivery ratio. They used 2 simulation scenarios where in the first scenario comparison was made on different mobility model varying different number of nodes 5, 10, 15, 20, 25 with fixed speed of 15m/s and in other case comparison was made to evaluate the protocol on different mobility models with varying speeds 5, 10, 15, 20 m/s and 50 nodes as constant all through. They concluded that Random waypoint model is best for AODV compared to other mobility models as the protocol produces highest throughput than compared to others.Other related work from (Nyirenda, 2009) gives the similar working of MANET routing protocols AODV, OLSR, DSR and TORA on OPNET 14.5. Their work carried out for study the performance of the four protocols by different performance metrics which are Network load, Packet delivery ratio, Packet end-to-end delay and Throughput. The simulation setup which was implemented on 6 different scenarios where the traffic passing on to the network was ranging from low to high network load, nodes changing from 5, 20, 50 and with speed ranging from 10 m/s to 28 m/s. Mobility model used in this was Random waypoint model for mobility pattern. They conclusions included in their work showed that OLSR performed better compared to the other protocols as it has a bad routing overhead and hence it is well suited for large and complex networks. So apart from routing overhead OLSR performed better but with routing overhead DSR is better. But when in small network AODV is much better compared to other protocols. So finally, proactive protocols perform well in high capacity links whereas reactive protocols perform better in low capacity networks.From another paper (Maltz, 2001), we see that working on demand routing protocols in MANET was done where DSR protocol was compared to other on demand protocols like AODV, TORA and DSDV. Simulation setu p carried is represented in tables belowWith the above simulation setup the protocols were evaluated based on the performance metrics used which was Packet delivery ratio, Routing overhead, Path optimality and lower speed of nodes. The conclusions showed that DSR performed well when referred to packet loss rate and routing over head is concerned. Of all careful implementation done with all the above parameters tested on the experiment test beds DSR out performed in every case scenario used when compared all the other protocols used in this setup.2.3 Background WorkA network can be said as association of different systems or organizations where sharing the information can be done collectively. Whereas in computing terms it can be simply defined as a group of computers connected together logically to share information like printing, faxing, etc The network can be divided into 2 types based on their working behaviour. They areInfrastructure network These networks are used where the top ology is said to be limited and there is a fixed point like base station (generally referred as router) to transmit signals and the end points which are connected to base station communicate with each other devices on the network switching from one base station to another. When a node moves out of range within its network, then it is said to be connected to another base station range where this process is referred as handoff. We can often see this type of mechanisms in infrastructure and fixed or wired networks.Infrastructure less network These networks are a typical type of networks where there are no such fixed nodes or topologies on the network and the end pints or devices on the network are free to communicate with each other devices on the network as each device on the network behave themselves as routers and encourages communication process all over the network. By this we can say that wireless technology is a promising technology that can tolerate the information exchange wor ldwide. In the last decade we can also see the constant increase in the growth wireless technology issues, one of which being mobile devices such as laptops, cell phones, PDAs etc Ad hoc networks are also the part of this type of network.Mobile Ad hoc network is a new technology emerged with the hypothesis of wireless networks. These networks are very typical and do not use any fixed infrastructure for communication process. The nodes connected in these networks are wireless links which are mobile in nature and communicate with each other mobile node in the network with radio transmission and topology is said to establish by the intermediate nodes on the network which are helpful for communication process. As there are no fixed infrastructure and limited topology constraints the nodes on the network are free to join and leave the network and this is possible as the nodes on the network are mobile. Due to this random movement of the nodes in the network the topology of the network ch anges dynamically. Due to this change protocol must be able to acclimatize with these movements and are also responsible to maintain the routes of the information travelled without disturbing network connectivity.This concept of ad hoc network allows each node on its network to act like router, resulting in the flow of information exchange with multi hop routing. These types of networks are widely used in military and other rescue applications. (Saadawi, 2003)2.4 RoutingRouting is the process of moving the data from one place of the network to another. The one end should be the source which intends to transfer the data to the destination (other end). The concept of routing has been there since 1970s but it has caught the move in 1980s. In 1970s networks were simple and today there are large scale networks in existence. To move the data from one host to another at least one router is required in the network. Router has all the information regarding hosts in the network and it can man ipulate the best possible route as well. (Javvin, 2004)Routing takes place at Layer 3 in OSI 7 layer Model. Some of the protocols at layer 3 are IP and IS-IS. These protocols carry the data between source and destination along with their addresses in the data packet. Routing involves two basic activities Path Determination and Switching. These two activities are capable to determine the optical routing path and to transfer the data packets through internetworking. This is called Switching. Switching can still be easy where as determining the reliable path is difficult.Path DeterminationRouting make use of the different routing protocols to determine the best possible path to deliver the data. Routing protocols use the metric to calculate which the best possible path to accomplish the task is. The metric used could be path bandwidth, path length, delay etc. to determine the optimal path. To determine the path in the network, routing algorithms maintains the routing tables which are u sed to store the routing information about the network. Routers communicate with each other in order to maintain their routing tables which make communication easier and faster. Routing information can vary according to the routing algorithm used for the process. (Cisco, 2010)SwitchingApart from path determination, router shows one more activity Packet Switching. Switching simply means forwarding the required data from one interface to the another in order to reach the destination. In this case, the data to be forwarded is packet. The next interface address is decided by using the destination address present in the packet. Though the nodes know the next hop address, they still need to know how to use it. So for that reason they use routing tables. The routing table throws the packet away when the destination is unknown. But when the destination is known routing table posses all the interface information forming the route to the destination. (2006)The next hop address could be anothe r host or either it could be a router. According to ISO developed hierarchical terminology, the systems which have the capability to forward the data from the source to the destination are called Intermediate Systems (IS) and the systems which fails to do so are called as End systems (ES). When it is a router it follows the same procedure as this one, and if it is a host it simply forwards the packet. In packet switching, the Layer 3 address of the source and the destination remains the same to authenticate the original sender and the receiver. However the Layer 2 address (MAC) changes from router to router and from router to host which at last determines the destination host. (Cisco, 2010)2.5 Ad hoc NetworksAn ad hoc network is a collection of many autonomous nodes connected together by radio waves and maintain the connectivity in decentralised manner. Wireless ad hoc networks are connected through wireless links so there is no need of any physical medium and hence contend of the m edium is always there such as noise, interference and fading. On ad hoc networks each node functions as a node and a router itself. It simply means there is no need of an additional switch or a router to route the data and the control is given to the nodes themselves. (Yang Li, 2010)2.6 Mobile Ad hoc NetworksA Mobile Ad hoc Network is an autonomous network formed by hundreds or thousands of nodes. These networks dont need any infrastructure as they can act as a node and router itself. They are free to move anywhere in the network and are connected through radio links. The only limitation with the MANETs is that they can communicate in a particular rage of the radio waves and outside the network they need some additional arrangements to communicate. To overcome this limitation the Intermediate Node or sometimes called as Relays are brought into picture. Intermediate nodes help in forwarding the packets to the destination. In MANET nodes are free to travel anywhere in the network, hen ce network topology cannot be fixed for such networks and it keeps changing depending on the current location of the nodes. (ANTDS, 2001)The fundamental differences between the wired networks and MANET areAsymmetric LinksRedundant LinkInterferenceDynamic Topology2.7 Characteristics of MANETsThere are several MANET routing protocols which should handle the several inherent characteristics of MANETs as follows as mentioned in (Subbarao)(Jain, 2005)Dynamic Topologies Since the MANET is infrastructure less ad hoc networks, the nodes are free to move arbitrarily. The mobility of nodes may be random and so unpredictable. So the links between the nodes may be unidirectional or bidirectional at times.Bandwidth Constrained, Variable Capacity Wireless Links Wireless links generally are bandwidth constrained. Since there is a lower capacity in wireless links as compared to the wired links, the traffic congestion is typical rather than different.Energy/Power Constrained Operation Energy consump tion is vital in MANETs as these nodes operate typically off power limited sources. Some or all nodes in MANETs rely on batteries.Limited Physical Security Wireless networks like MANETs are more vulnerable with the security issues available with them. Issues like eavesdropping, jammer attack, spoofing and denial of service attacks must be carefully considered.2.8 Need of MANET Routing ProtocolsA mobile ad hoc routing protocol is used to discover new routes and maintain the existing routes between the nodes in the network. MANET (Mobile Ad Hoc Network) is the collecting of mobile nodes which are present in random manner in the network has the capacity to communicate and exchange information effectively over the network by facilitating the intermediate nodes for their communication. The essential task of a MANET protocol is to create or discover the correct and efficient routes between the nodes so that information can be delivered accurately with respect to time. Route construction s hould be done with less overhead and minimal bandwidth consumption for effective communication.2.9 Applications of MANETsApplications of MANETs can be used in many critical situations today and are increasing widely. There are many applications of MANETs today and some of them are mentioned here. An ideal application is for search and rescue operations. Such kind of operations is characterized by the networks without having an infrastructure present. One of the reasons for this may be because all of the equipment was destroyed or may be the region is too remote. Rescuer must be capable of communicating to use their energy fairly and also they must maintain the security. Carrying the equipments for communication that the rescuers are already using makes the job easier.The commercial application for MANETs includes computing everywhere which means the mobile devices are free to move anywhere in the network and yet it is possible to be in communication with the devices. The computers a re allowed to forward the data to another computer or data networks may be extended far beyond the considered reach. Such networks may be more widely available and much easier in use.Another important application of MANETs is Sensor Networks. Sensor networks are composed of very large number of small sensors which are able to detect number of properties of the area, for example temperature, pressure, toxins, pollutions etc. In this case, the capability of sensor network is much limited. So there is always need to forward data to the central computer and for this purpose they have to rely upon others in order to forward data to the central computer. The sensor networks individually are limited in their computing capabilities but together can be very effective and the key to future homeland security. But individual sensors because of their limited computing capabilities can prove prone to failure and loss.There are many other applications of MANETs like personal area networking where the communicating nodes may be mobile phones, laptops etc. Also this has a potential in military operations with the nodes of the network as soldiers, tanks and airplanes. Many more areas includes civilian environment to diverse taxi cab networks, conference rooms, boats and ships. (Bluetronix, 2006)2.10 Classification of Routing ProtocolsAccording to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categoriesTable driven (proactive) Routing2.10.1 Proactive (Table-Driven) Routing ProtocolsThese routing protocols are similar to and come as a natural extension of those for the wired networks. In proactive routing, each node has one or more tables that contain the latest information of the routes to any node in the network. Each row has the next hop for reaching a node/subnet and the cost of this route. Various table-driven protocols differ in the way the information about a change in topology is propagated through all nodes in the network. (LinuxOnly)In proacti ve routing protocol each node maintains the up to date routing information of all nodes in the network. Here each node maintains the routing table and broadcast it when there is a change in network topology. As soon as source needs the route to the destination it can select from the routing table. The routing table is exchanged periodically by broadcasting to all nodes in the network to keep track of the new message even though the topology is not changed. Each nodes has the routing information of all nodes in the network though most of it undesired. Advantages of proactive protocols are that the communication experiences a minimal delay and routes are up to date. Disadvantage is that the routes are broken as a result of mobility of nodes. (Chang)Following are the examples of table driven protocols GSR and OLSR and some other proactive routing protocols are FSR, HSR, ZHLSR, CGSR and WRP etc.2.10.1.1 OLSR (Optimized Link State Routing)OLSR Protocol is based on traditional link state algorithm which supports point to point routing strategy. In this strategy the nodes keeps exchanging the information periodically in order to maintain the network topology within the network. OLSR is an optimization version of link state protocols. That means it keeps flooding the topological changes information to all the hosts across the network when happens. OLSR is also proved beneficial for the reason that it minimizes the size of each control message exchanged and also it avoids each node to rebroadcast during the updating of the routes. It uses the Multi Point Replaying (MPR) strategy to do the above task. For MPR strategy each node creates a set of all of its neighbouring nodes, generally called multipoint relays of the node, in the network to transmit the packet once again. Each node in the particular set can receive and process the packet but only cannot retransmit it. To use MRPs, each node has to keep broadcasting periodically to all one hop neighbours using hello messa ges. Another method to reduce the overhead is to provide the shortest path. When the time interval is reduced for the control messages transmission, it can prove more reactive to the topological changes (Kuosmanen).The implementation of OLSR protocol basically uses two control messages Hello message and Topology Control (TC). The hello messages are to be sent only one hop away from the host and are used for finding the link state information and hosts neighbours. MPR selector sets are constructed with Hello messages which explain which host in the network has chosen this host to act as MPR and using the information the host can select its own set of MPRs. The Topology control (TC) messages are to be broadcasted across entire network about the advertised neighbours and it includes at least the MPR selector list. As OLSR is proactive approach and it keeps updating the routing table periodically, the TC messages are also broadcasted periodically and the hosts with MPR selector set can only forward the TC messages.There can also be MID message which is Multiple Interface Declaration message to declare that the announcing hosts can have multiple OLSR interface addresses. And again MID message are broadcasted throughout entire network and only by MPRs.2.10.2 Reactive (Source Initiated) Routing ProtocolsThese protocols take a lazy approach to routing. They do not maintain or constantly update their route tables with the latest route topology. Reactive routing is also known as on-demand routing. The Reactive Routing Protocols are also called as Source initiated Demand Driven protocols. They are called so because the routes are discovered only when needed by source.Source initiated on demand networks cerates routing only when desired by the source node. When source wants to communicate with destination then it invokes the route discovery mechanism to find the path to the destination. The route discovery process is completed once a route is found or all possible are ide ntified. Once the rout is formed between source and destination it is maintained by a route maintenance procedure until the destination becomes inaccessible or the route is no longer desired. (Chang)These Examples of reactive routing protocols are dynamic Source Routing (DSR), Ad hoc on-demand distance vector routing AODV, ABR, SSA, CBRP, and RDMAR.2.10.2.1 AODV (Ad hoc On Demand Distance Vector)Ad hoc On Demand Distance Vector protocol as the name implies it is an On Demand that is, Reactive Protocol. AODV is capable of both unicast and multicast routing. It is an on demand algorithm, it means that it builds routes between nodes only as desired by source nodes. It uses the concepts of DSR routing for route discovery and route maintenance and DSDV protocol for the concept of sequence number. It uses sequence number concept to ensure the freshness of routes. The ad hoc on-demand Distance vector algorithm facilitates the self-starting, multi hop and dynamic routing between participati ng nodes to establish and maintain an ad hoc network. AODV algorithm enables the nodes to find the routes for new destinations as and when they are needed and the nodes are not required to maintain the routes to the destination that are not in the part of active communication. It also enables the nodes in the formation of multicast groups and enables the nodes to respond quickly to link breakages and topological changes in the network thus the operation of AODV is loop free and thus avoids the Balham Ford count to infinity problem.AODV routing protocol is a simple and effective routing protocol for Ad hoc networks. It also uses the concept of hop by hope routing and sequence numbers from DSDV protocol.The following are the message types defined by AODV they areRoute request (RREQ),Route replies (RREP),Route error (RERR) and group hellos (GRPH) this message types are handled by UDP and IP header.The route request message format contains the following fieldsSource address the address of the node which originates the route requestSource Sequence number the current sequence number to be used in deciding the route for the source requestDestination address the address of the target node for which the route is initialized.Destination Sequence numbers the sequence number received by source for route towards the destination.Broadcast ID The sequence number by which a RREQ route request can be uniquely identified.Hop counts the number of the hops to be taken from the source node to reach the destination node that handles the Route request.The Route Reply message format contains the following fieldsDestination address the address of the destination node for which the route is aboundedDestination sequence number the destination sequence number related to the routeSource address the address of the source node that originates the route requestLifetime the time for which nodes receiving the route reply considers the route to be valid.Hop counts the number of hops to be taken from source to destination.The route error message format contains the following fieldsUnreachable destination address The address of the destination that has become unreachable due to link failure. (Arbia, 2008)In AODV the only nodes that take active participation in routing process are the nodes that sit in direct path between source and destination. The nodes which do not lie on active path do not take participate or maintain the routing table, thus AODV minimize the number of control messages sent between two nodes. As long as there is a valid routes between the source and destination for communication, AODV does not play any role and when a new route to a new destination is required and if the route to the destination does not exist only then the source node initialize the route discovery process by broadcasting the RREQ message to find the route to destination. The

An Analysis of Cry, the Beloved Country :: Cry the Beloved Country Essays

An Analysis of Cry, the Beloved hoidenish In Alan Patons novel Cry, the Beloved Country two characters, Absaloms girl and Gertrude, show the how society in Johannesburg is as a whole. Absaloms girl symbolizes how girls her age are mothers and have even become divorced some(prenominal) times before. On the other hand Gertrude, Kumalos sister, illustrates the qualities of a young woman who becomes corrupt from Johannesburgs filthy system of stealing, lying, and prostitution. Both of them show the directions of Johannesburg as a whole. When Gertrude is first found, by Kumalo, she is seen as a ragged and dirty person making her living as a prostitute. When Kumalo sees this he thinks of how she could have a ofttimes better living if she came back with him. This is, in essence, the same thing that Kumalo and the blacks are trying to do to Johannesburg. These people are trying to fix the corruption that has taken place in the city. Gertrude, like many others who have come to Johannse burg, or who were even born there, were brought to a world where corruption is the key to living. This is the only way to make a decent spirit and so they stoop to the lowest levels possible, cheating and prostitution. And just like the rest Gertrude cant be saved from what has become. Even though Kumalo tries to save her and the city of Johannesburg from what it has become it is known that once they have become what they have its impossible to change them back. Absaloms girl, on the other hand, symbolizes how the society gets into many difficulties at a very young age. This girl has already had several husbands and has a child. Like the rest of the population of Johannesburg she has been confronted by something she is not ready to face. Because of the way of life in this city her choices, along with many others, is half chance. Even though it seems to be the right thing it isnt the same outside of the city. Symbolism is also shown through and through Absaloms girl to Absalom. Many people, in Johannesburg, have spouses who make a living by doing many bad things including stealing. Also, a great number have deep in thought(p) someone because of what they do, either by death or by getting arrested and prosecuted. Either way the people are taking a risk and it is shown by what happens to Absalom.

psychology: male eating disorders :: essays research papers

Eating Disorders are psychological disorders that result from a drive to be thin. They are broken down into three categories, anorexia nervosa, bulimia nervosa, and binge-eating disorder. Anorexia nervosa is diagnosed agree to the DSM-III-R in individuals with body weight that is significantly lower than the norm, extremely concerned with weight and shape, distorted self-image, and an absence of three consecutive menstrual periods, in women. bulimia Nervosa is diagnosed according to the DSM-III-R in individuals who have recurrent binge eating episodes, have weight and shape concerns, have a lack of control over such behavior, and have compensatory behaviors (e.g., vomiting, fasting, misuse of laxatives, or excessive exercise). Binge eating disorder has much of the same criteria as Bulimia Nervosa with the exception of the compensatory behaviors.      This study has several goals. First, the authors compare men with eating disorders to women with eating disorde rs, specifically to find clinical similarities. Because eating disorders are considered rare in men, the authors set out to investigate the differences between the twain sexes. Second, the authors wanted to find differences in men with eating disorders and normal men. The authors also set out to find a representative sample that would provide the sterling(prenominal) validity. Concentrating on men with eating disorders, the authors also were looking for a correlation between eating disorders and other psychological disorders, such as affective disorder, anti-social record disorder, and substance abuse. On the subject of sexual orientation, the authors explain, "...although an obvious area of investigation, (sexual orientation) was deemed too sensitive a topic for a government-sponsored survey and unfortunately was not assessed". method     Subjects      Sixty-two men meeting the DSM-III-R criteria of an eating disorder, 212 women w ith equivalent eating disorders, and a control group of 3,769 men who had no presence of an eating disorder.     Measures     Community survey. stochastic houses were selected in Ontario. From each household an individual aged fifteen years and older was chosen at random and then administered the Mental Health subjoining to the Ontario Health Survey. The individual was then asked to submit written informed consent prior to the interview. A sample size of 9, 953 individuals was obtained by these means.     Subject reduction. Using the University of Michigans rendition of the World Health Organization Composite International Diagnostic Interview, the subjects were narrowed down. During this process, individuals were interviewed for one to two hours by trained interviewers. The subjects were assessed for anxiety disorders, substance use and or abuse, affective disorders, anti-social personality disorder, and of course eatin g disorders.