Effects of advertising Essay

Advertisements are everywhere, traveling by all ways possible, infiltrating the privacy that every person holds important to themselves and their family. American Marketing Association defines advertising as â€Å"the non-personal communication of information usually paid for and usually persuasive in nature about products, services or ideas by identified sponsors through the various media.† Today, with the development of the technology and the diversity of the mass media, advertising has influenced us pervasively in our daily life. Advertising has been applied in most of fields in society such as economical advertisings, educational advertisings, political advertisings, and healthy advertisings, etc. Advertising is used to promote goods, services, images, and anything else that advertisers want to publicize. It is becoming a major part of mass media. We may view it positively; at other times we may just skip or ignore it. In order to attract audience, advertisers use various techniques on their advertisement to make people aware of the firm’s products, services, or brands. Although the methods used by advertisers are infinitely, they have a common goal to persuade those who may become their customers to buy their products. An excellent advertisement will create a deep impression on its potential customers through particular techniques. They deliver their advertisement through TV, radio, magazines and newspapers, internet, billboards, and other multi-media means. By advertising, individuals or companies are able to get more extra profits from their products, promote their products, and gain the most important purpose – to sell. In many cases, there are some negative effects – some annoying hindrances in our daily lives. It makes our nerves, distorts the truth, and adds to the cost of the product. Advertising is designed for one purpose – to sell. To achieve this goal, advertisers are willing to stretch and distort the truth, just to convince people to buy their products. For example, an advertiser  may convince buyers to purchase their products by stating those have been tested and found superior. In reality, the products are not better than any other – the tests themselves doubtlessly conducted by the promoting company – conducted to ensure at least something is superior about the product, even if it is only the color. These advertisements are worded carefully so that they are telling the â€Å"literal truth† – the truth is exactly what the words say, although people misinterpret the message by using conversational logic as something different – something better. By using ingenious tactics like these, the populace is deceived into buying a product that may not do what is required, or a product that a buyer may have never needed. That is why advertising is not good for our society. First, I would like to discuss about the negative effects to children and youth. One of the most corrupt forms of advertising comes from cigarette companies. According to some investigator, â€Å"Cigarette advertisements are degrading not only because the products behind them are proven to be a health hazard, but also because the advertisements are focused toward younger generations.† Many advertisements use young, attractive, healthy looking models when advertising for a brand of cigarettes or beer. Company promotions have led people to affiliate certain products with feelings of happiness or euphoria. There is no doubt that people smoke the most heavily advertised brands of cigarettes. â€Å"Tobacco advertising increases young people’s risk of smoking by using themes that appeal to them, such as fun times, action, and being popular and attractive.† (Family Education 1). Advertisings that supply the Surgeon General’s warning along with the main body of the message are blatantly contradictive. These advertisings prove that there are many forms of advertising without any morals, and that companies will go to great lengths to have their name and image promoted regardless of the results. The nation’s companies have put themselves before the children. Similar to the case of cigarette companies, Ph.D. Henry Saffer show that spending money to advertise alcohol contributes to increase the rate of students drinking. Alcohol remains popular with American college students, as indicated by the Core Institute Survey (1998). In 1997, 84.2% of college students reported drinking alcohol, an increase of 2% over the prior year. For comparison, there were similar increases in the prevalence of tobacco and marijuana use. Moderate to heavy drinking also increased with corresponding reductions in abstention and light drinking. Nationwide, students reported consuming an average of 5.64 drinks per week in 1997, up about 7% over 1996. The Core Institute also reported that 45.5% of students had consumed five or more drinks in one sitting in the previous 2 weeks. More than 21% of the students reported three or more episodes of this kind of high-risk drinking in the previous 2 weeks. Finally, more than 90% of American college students reported that drinking is a central part of campus social life. (Henry Saffer, Ph.D., Alcohol Advertising and Youth, pg. 173) According to Competitive Media Reporting, more than $1.2 billion was spent in 1998 on alcohol advertising in measured media (i.e., print media, outdoor advertising, radio and television). An additional two-thirds billion dollars was spent on other forms of promotion, including sponsorships, couponing and direct mail. Alcohol advertising had decreased from 1987 to 1996 by 34%, in real terms. However, since 1997, alcohol advertising has been increasing. Part of the recent increase includes the use of cable television by spirits advertisers. (Henry Saffer, Ph.D., Alcohol Advertising and Youth, pg. 173) Second, advertisements can change or impact an individual’s behavior, attitude, expectations, or relationships. The more advertising that a person watches the more that they are influenced by it. The more that they are influenced by advertising the less important their relationships become. Consequently, the behaviors that we display and the influences on our physical environment are directly affected by the amount of advertisements that we see. In the world of advertising, lovers are things and things are lovers (Kilbourne, Can’t Buy My Love: How advertising changes the way we think and feel, pg. 77). Sadly, advertising promotes a corrupt and bankrupt concept of relationships (Kilbourne, Can’t Buy My Love: How advertising changes the way we think and feel, pg. 77). It is unavoidable and extremely damaging to our relationships and especially families. With the divorce rate and domestic  violence rate at the highest it has ever been, it is necessary to evaluate the influences of advertising to our relationships. It has become more and more difficult to relate to our partners in a manner that isn’t objectifying and exploitative. These are images that are forced into our heads and we may have very little control over. Moreover, advertising creates images of what is appropriate behavior in a relationship, using products. That behavior is not always one that is idealistic for real life relationships and generally can be very damaging to intimate and personal relationships. Advertising plays a part in dictating our expectations of our mate, ranging from money and clothing to behavior and attitude. Therefore, when messages and images are repeatedly presented to us they inevitably have an impact on our relationships. Our intimate relationships have been trivialized and our relationships with products have become more important. Another negative effect is that some advertisings use the sexual content to attract the attention of consumers. Consistently, studies have demonstrated that sexual appeals attract attention to the advertising, typically without a corresponding advantage for brand information processing. Sexual content may be eye-catching and entertaining, but it may not be communicative and might distract the viewer from the message. Reichert, Heckler, and Jackson (2001) claim that when sexual stimulus is used in advertising, viewers’ perceptual and processing resources are directed toward the sexual information in the ad rather than toward the brand. Therefore, they will not have a perspicacious decision to buy the products. Recently days, on the television, some company try to develop the crazy adverting project that use women’s belly to advertise. They make some small advertising boards and they paste them on the belly of women and then they ask them to wear short skirt and bikini, after that they will go around some public locations. In this case, it is very stupid that it can promote the women’s body not the products. Finally, use sexual content to advertise is one of the negative effects of advertising that is worse in the society. Throughout history politicians have used various methods, such as persuasive speeches, political advertising and political rallies, to achieve their â€Å"primary goal, the winning votes†. But according to the results of the  research made by Won Ho Chang (Professor and Director of the Stephenonson Research Center at the University of Missouri’s School of Journalism), Jae-Jin Park (Public Relation Specialist with LG Corporation in Seoul, Korea) and Sung Wook Shim (graduate student in the School of Journalism at the University of Missouri) in 1998 â€Å"over the years, politicians have found that it is most advantageous to use political advertising to persuade voters†. For example, the majority of presidential campaigns depend on television advertising. Clinton spent $12 million of his $30.9 million limit on television commercials in the middle of the primaries, $42.4 million during reconvention, and $44 million on television ads in the general election. A total of $98.4 million was used on television commercials. In my opinion, it is not good for the citizens and will influence on the result of voting. The voters will receive much positive information of the politicians and they will be distracting the purpose of vote. Moreover, by using an effective political advertising, a politician can win the other politicians even though he is not as good as the others, and it is unfair to them. There are no a commission to check the information of political advertising that is wring or wrong; therefore, the voters will have no chance to predict what the politicians will do for them. Some politician just tries to get votes by any ways, and when they win they forget what they promise. In short, advertising in voting is not a good method and it also makes some disadvantage to both the politicians and the voters. The last problem is that some activities in our society are wrapped by the advertisings. On the streets of our city, many advertising billboards are built to advertise for some products and it makes he city become uncivilized. On the television, there are many programs of advertising that trouble the audiences. For example, when people are attracted by a wonderful program, some adverting programs are run and distract them. More over, on the Internet, now people get many difficulties to check their e-mail in the inbox because they have seen many advertising letter from some company in their inbox. In short, some of advertisings are now obstructing the process of some activities in our society. Advertising has a strong influence over social behaviors, attitudes, and  expectations of individuals involved in intimate relationships between men and women Companies spend millions of dollars on advertising every year. The companies are very aware of the effect of advertisement on the community. Companies would not spend millions of dollars on advertising if it had little or no effect on the public. We all know that advertising provides a general service of informing us about products. But, does it also unnecessarily affect our behavior, relationships, and environment? How can we avoid the negative effects of advertising, especially in our relationships? Nowadays, in order to promote the products, many companies abuse so much of the advertising. In this case, they do not pay enough attention to the quality and the value of the products. Therefore, although advertising can bring them the profit and promotion from selling their products, they have to consider some bad effects of them on the society. References Family Education Network â€Å"Cigarettes – Don’t Believe the Hype† cited in 18/12/2004 at www.familyeducation.com Henry Saffer, Ph.D., Alcohol Advertising and Youth, National Bureau of Economic Research, 365 Fifth Avenue, 5th floor, New York, New York 10016-4309 Kilbourne, Jean (1999). Can’t Buy My Love: How advertising changes the way we think and feel. New York: Touchstone. Andrea Dworkin, Pornography: Men Possessing Women (New York: Phime, 1989) Reichert, T., Heckler, S.E. & Jackson, S. 2001, the effects of sexual social marketing appeals on cognitive processing and persuasion. Journal of Advertising, vol. 30, no. 1, pp. 13-27. Won Ho Chang, Jae-Jin Park, and Sung Wook Shim. â€Å"Effectiveness of Negative Political Advertising.† Cited in 21/12/2004 at http://www.scripps.ohiou.edu/wjmcr/vol02

Sarcasm in News

North Korea, one of the most modern country in the world and well know of their great military power to protect their own country per their own claim. The government has spent huge amount of money in development of their weapon technology : from nuclear bomb to missiles. The citizens of North Korea are too proud of having such a wise government to allocate all their resources on weapon development instead of economics. They have been living peacefully. This Just mirrored a quote from Steve Jobs : stay hungry, stay happy ( originally Is stay hungry, ATA foolish).A Democratic Presidential Election? As they want to be a member In the democratic world. , recently, they conducted a presidential election. What they believe Is this mechanism can serve a tool to shake hand with the western and express their democratic culture. The voting system Is designed as below: the voter will be given a choice. The ballot paper contained two boxes: one In which to vote for the party , and another where anyone who doesn't support the ruling party could write their name and address.As you can see, the voting process is widely open without anonymous vote. Isn't that wonderful? No need to be anonymous, just let everyone know who's your best choice. Eventually, the election is fair, open and peaceful. What percentage of the vote do you think: 52%, 63% or 85%? The answer is 100%. According to the official report, it said that 99. 97% of all registered voters across the country participated in the election, and 100% of them voted for the candidates were elected. The outcome equally expresses the absolute support and rust of all voters in the country.After the election, they have received congratulation letter from Iran : they described my election as â€Å"overjoyed to see that the hearts of the Korean people are fully behind their glorious chairman. † The U. S. President Obama is busy with his golf game and can not response this immediately. The only candidate and the final winne r Kim Gong-UN encourages him to comment this election result on his Face Book. The greet leader is willing to offer the successful experience to America.Sarcasm in News By Minnie eroded a quote from Steve Jobs : stay hungry, stay happy ( originally is stay hungry, stay foolish). A Democratic Presidential Election? As they want to be a member in the believe is this mechanism can serve a tool to shake hand with the western and express their democratic culture. The voting system is designed as below: the voter will be given a choice. The ballot paper contained two boxes: one in which to vote for the party , and another where anyone who doesn't support the ruling party could without anonymous vote. Isn't that wonderful? No need to be anonymous, Just let

Planning in Organisation for Creative Workforce Essay

Planning in Organisation for Creative Workforce - Essay Example This suggests that most of the organisations fail to utilise its workforce due to lack of planning leading to employee dissatisfaction. An employee who does not find any motivation into the job he performs, learns nothing out of the routine work, is not rewarded for any outstanding performance, and sees no challenge in his job is less likely to be motivated to work enthusiastically and perform at his best. Bramham (1987) propounds the most important aim of human resource planning in an organisation to foresee future need for employees not only in quantitative terms but also in qualitative manner such as the skills, calibre, performance and attitude required for particular types of jobs. Dessler (1999, p2) says that human resource management is all about devising policies and strategies for the employees working in the organisation. It includes selecting, training, evaluating, appreciating and providing convenient working environment for the employees. It shows that planning for creative workforce is very crucial for the survival and success of an organisation. The organisations use planning to select the kind of personnel it needs, motivate them and retain them towards future enhancement of organisational objectives. The organisations plan to realise organisational needs for workforce in future and take calculated steps to retain its employee through various means. In fact, human resource planning does not only enable an organisation to retain its employees but also to 'treasure' them so that they can gain more creative and efficient workforce. The use of planning by organisation to gain more creative workforce... Planning is the most important aspect of organisational management. Workforce planning is the key to acquire the kind of people the organisation needs and to retain them through various motivating factors such as salary, promotion, job security, learning opportunities, performance appraisals etc. It shows the criticality of organisational planning concerning human resource. Every organisation needs to plan in a proactive manner the labour needs that will arise in future. It will ensure that the organisation strives to attain the employees with suitable skills and attitude to train them for upcoming change. In this way, the organisation will have the 'right team' prepared for challenges when the time actually comes. Mullins (1996) maintains that human resource planning if done in an efficacious manner can enable the organisation to take imperative steps for the enhancement of employee productivity level at the right possible time. It assists the organisation in meeting all the necessary human resource requirements from hiring to firing in a systematic way. This reflects that human resource planning makes an organisation realise the factors undermining the productivity and calibre of its employees keeping them from achieving organisational objectives before it becomes too late. Most of the organisations do not actually plan to acquire highly qualified and skilled labour force, but most often to retain the employees on whom the organisation has already exerted substantial money and time. It mirrors that organisation will risk the creativity of its workforce if it does not properly plan for the development of its employees. Mathis (1997, p314) suggests that, â€Å"development can be thought of bringing about capacities that go beyond those required by the current job†¦As such, it benefits both the organisation and the individual’s career†.

Sensory Disabilities Essay Example | Topics and Well Written Essays - 250 words

Sensory Disabilities - Essay Example the blind man crossing the road alone is a sign of bravery and his this act is also showing that he is a part of the normal society of Canada, but, still it is quite dangerous and he can be the victim of a terrible accident, unlike the normal people who are able to see the vehicles on the road before crossing it. A solution to this problem can be the awareness among people that they should take care of disabled people and help any blind man crossing the road alone. The drivers should also be careful and not drive too fast. If the car and bike drivers drive fast and an unexpected blind man is seen crossing the road, the vehicle will not be able to bear the prompt break by the driver and can slip and slide over the snowy slippery road and cause a dreadful accident. Hence, such precautionary measures and care should be taken to avoid any harm to the disabled people, and encourage them to be a part of the normal Canadian

Undecided Research Paper Example | Topics and Well Written Essays - 2250 words

Undecided - Research Paper Example As international trade is complex and requires greater documentation and control, international commercial banks are actively involved in facilitating it by providing financial instruments that cater to exporters and importers. The role of commercial banks in international trade is of utmost important as they provide reliability and assurance to their clients, and provide an easy process to finance trade. This report will cover many aspects of international trade finance. It will focus on the financial instruments that are used to make payment in international trade, the parties involved in international trade finance, and trade finance methods. ... finances the trade cycle from the production till the goods are bought by the buyer and may require financing from the bank to support the production process. In most international trade transactions, the buyer and the supplier have separate banks that act as intermediaries to the transaction. Cash-in-advance The prepayment method involves cash in advance paid by the buyer to the seller. It is a risky and expensive method for the buyer but it may occur in cases where the seller is a long time business partner or a trustworthy party and the buyer is new in the market. In this scenario, the buyer will transfer the payment through his bank to the exporter’s bank account. This is the safest method of financing for exporters as they do not ship the goods till the payment is received from the importer. Letter of Credit A letter of credit is one of the most commonly used financial instruments in international trade. The letter of credit is a document that the importers bank issues pr omising to pay the exporter upon presentation of the relevant shipping documents such as bill of lading or bill of exchange in accordance with the terms agreed. This provides greater guarantee for the exporter as the bank is a more reliable creditor than any importer and it is easier for the importer as the bank will not release payment till the legal documents have been received. Although, this is riskier for the exporter as compared to the prepayment method, it is a secure was of transferring payment. The letter of credit stands even if the importer is unable to make the payment, thus the issuing bank is liable for the payment to the exporter and not the importer under the letter of credit. In cases where the exporter fears that the issuing bank’s guarantee is not sufficient, which could be

Discussion-WK4 Essay Example | Topics and Well Written Essays - 500 words

Discussion-WK4 - Essay Example His proposal approves that the solution works. He has also included an analysis of the plan and the possible results. Karen’s argument will absolutely suit her programs but will require the approval and consideration of others. She does everything to convince her boss that her idea is the best. She is not over confident that her idea will be approved and so she offers her idea put to test which is a good quality of a proposal. Proposal on nurse shortage has had a pre-test with reasons highlighted. It provides the reader with relevant facts making it meaningful and convincing. The thesis statements of the essays are effective because they assure the reader that the problems can be surely be solved effectively. Everything in the proposals has revolved around the problem and the effective ways to solve them. The opening paragraphs of the essays are effective since they have outlined the area of discussion in the essays. The reader can get the important information that is needed for the final decision. The ideas are not concealed between needless words. The points to be put across are to the point and clear. Generally, they have clearly stated the purpose of the proposal at the beginning. The closing sentences as expected should depart with a discussion resolved. The essays do not have repetition of sentences unless for words that requires emphasis. Request for schedule change has shorter paragraphs of one sentence each. The paragraphs are wordy and require reviewing. An example is the paragraph that proposes the schedule the reasons for her proposal should have had each reason on each paragraph. This is the way everyone can understand your points. It also makes the proposal look perfect and attractive irrespective of the content (Trimble,

Assessment, Diagnosis, and Research Assignment Example | Topics and Well Written Essays - 500 words

Assessment, Diagnosis, and Research - Assignment Example Clinically, identification and evaluation of available resources are instigated in the assessment process (Vacc & Loesch, 2000). In typical function, assessment is foremost action towards therapeutic interventions. It is primarily employed in the aim of â€Å"screening for...psychopathology, treatment planning, and monitoring of (psychological) progress† (Krishnamurthy et al., 2004, p. 727). In the instance of inadequate assessment, the whole counselling activity is rendered unreliable. Illustrated in the case of geriatric clients in depressive states, some counsellors may mistake related symptoms as normal in the aging process (Benek-Higgins, McReynolds, Hogan, & Savickas, 2008). If properly assessed, conceptualizing the case can be more accurate, resulting in effective therapies and improved health status. Otherwise, clients may further suffer, as experts pass such conditions as natural. Upon complete clinical inquiry and screening, the next step is diagnosis. Black and Andr easen (n.d., pp. 4-5) provided a list of purposes that diagnosis performs, such as create an organized body of thought regarding complicated clinical events, â€Å"help predict outcome...choose an appropriate treatment...search for pathophysiology and etiology.† Diagnostic procedures make it possible for coordinating assessment data with existing diagnostic systems.

Interpretation Methods Essay Example | Topics and Well Written Essays - 5500 words

Interpretation Methods - Essay Example Scholarship and research are the basic requirements to achieve this goal.Many of England's museums were mainly established to promote learning. Although there are several other ways of learning but still, learning through objects is the most beneficial way. It is an interactive approach that can encourage the imagination stimulating an urge for discovery. The cumulative impact of museums on the lives of individuals as well as society is simply enormous. Many museums have already worked in partnership with a wide range of organizations in order to develop a better approach for learning programs. Most of the times, these activities take place inside the museum premises. But sometimes the museums take their collections and expertise out into public venues, residential homes, social gatherings, hospitals, prisons and schools. This can help us understanding the powerful impact of museum-based learning. In the last ten years, living history is becoming more and more popular not only among museum professionals but the historic house visitor. This process is well established and flourishing in the USA. The use of live interpretation in Britain is lacking both the status and methodology in comparison with the other side of the Atlantic. In short, it is in its infancy. The living history technique is still having a long way to go before its acceptance by many British museum professionals, as a valid and effective technique of Social History Interpretation, instead of a simple approach just for children or special events. This acceptance mainly depends on exploring the potential educational and learning experience offered to all the visitors. Living History Living history can be defined as being a direct form of live interpretation, first person interpretation. Drama and Theatre is excluded in the field of Education because that they do not necessarily require a factual or historical basis. Whereas guiding, demonstration of a craft and the third person interpretation are historically and factually based, but they do not require any mark able performance skills. Battle re-enactments are excluded because this form of presentation frequently has no educational object. It has no historical context and is not linked to any performance skills. It should be noted that only first person interpretation requires an interesting combination of historical knowledge, performance skills and educational objectives. History The first use of living history method was in Europe less than one hundred years ago. Artur Hazelius (1833-1901), who is remembered for the Open Air Museum, founded Skansen, the Museum of Scandinavian Folklore in Stockholm. It was started in 1873. Although the museum gained popularity, he

Private School Education Essay Example | Topics and Well Written Essays - 1500 words

Private School Education - Essay Example That would enable the government to support education without necessarily maintaining public institutions. The champions of this voucher system also say that the one-size-fits-all public school system is inappropriate as the model does not cater to the different needs of the students. Opponents of the voucher system, on the other hand, say that it is unfair to take public money meant for public schools and channel the same into the private school where the public has no oversight over how the funds would be used. There is also fear that the private school system may only help to further segment the population alongside religious, social class and other lines. It is entirely possible that the introduction of the voucher system in private schools would provide a magnet for students in public schools. Faced with a larger applicant's pool, private schools would then find it easier to reject applicants deemed undesirable. Unlike public schools, private schools are not obliged to take in one and all. Why the private school vouchers system issue so polarizing Part of the answer lies in the way it has been promoted. California was among the first states to flirt with private schools voucher way back in 1993. A proposal was brought into the legislature of the state that would have taken away as much as 10 per cent of public school funding, with a possibility of further increases on the card if more students moved from public to private schools (Rushefsky, 2002, p. 396). The issue is a political hot potato so much that George W. Bush stopped talking about it in the 2000 election primaries. Two powerful arguments already advanced are essential for a balanced view on the issue. And this article will chronicle the vouchers debate and will attempt to close the difference between the two sides through critically analyzing the pros and cons of the voucher system in private schools. Recurring discussions on the topics are decidedly one-sided. And once a path has been identified, for many an author on the topic, there is no turning back. Two critically acclaimed works on the topic include Rhetoric Versus Reality done by four RAND researchers; Gill, Tiampane, Brewer, Ross and Booker (2007). This book does a fairly good job examining the theoretical underpinnings of vouchers and charter schools and tables the empirical data on their efficacy. The book also looks at how several policy formulations such as the funding, eligibility criteria, academic standards and accountability, may affect the success of the program. Some issues which have yet to be addressed are raised, and although the book is not conclusive on those issues, it leaves room for a more robust consideration of the issues in the future. The other important work on the topic is The Education Gap by Howell and Peterson (2002). Compelling evidence is tabled that African Americans have greatly benefited from the voucher system. Overall, The Education Gap is illustrative on the practicability of the voucher program in private schools and emphatically so in poor urban environments. The point of convergence for both books is that the authors favour random field trials. The sheer volume of applications that are usually received reduces the voucher program into some form of the wager so that those who received the vouchers were merely lucky than needful. There are other studies/articles on the subject. Breaking These Chains is a book by Daniel McGrory, a former Whitehouse speechwriter that in an evangelical fashion roundly criticizes the public school system (1996).        

Mentoring in Practice Essay Example | Topics and Well Written Essays - 2500 words

Mentoring in Practice - Essay Example Mentoring is the process of supporting and guiding people with the aim of empowering them so that they can better manage and benefit from their own potentials, skills and advance their performance and reach where they want to reach. It is also a perfect tool for empowering and developing personal skills and helping people to advance in their careers. The process of mentoring, established under the principle of communal trust and esteem involves two partners, mentor and mentee, with the same objectives (Mentorset 2008). A mentor guides and helps the mentee to take the right direction towards achieving their careers. Mentors usually are people having the same experiences, having a deep understanding of the issue involved, and hence providing the mentee with the chance to reflect on the career options before him and make progress. Therefore, a mentor helps the mentee to believe in himself and uplift his confidence. Finally, the mentee will be able to understand better and direct his life towards a chosen destination (Ongycp n.d.) The roles and the responsibilities of a mentor are very diverse and complex depending on the question in consideration. The mentor does not decide for the mentee but only assists him to decide. The mentor only guides, facilitates and acts as a role model to the mentee towards where the mentee want to reach (Nakagawa 2012). As time goes, the roles and the responsibilities of the mentor may change depending on the changes in the objectives and needs of the mentee. This is because; each stage reached may require different strategies in order to move successfully to the next stage. However, as the goals, needs and objectives shift, the most important idea to keep in mind is that the mentor always ensures and guarantees the mentee his freedom to develop his own goals (University of Southern Queensland 2014). A mentor is an experienced person who provides guidance to the less experience one by enhancing trust and cultivating positive

Wetland And Water Environment Essay Example for Free

Wetland And Water Environment Essay Introduction Ecological restoration has been proven to be a very difficult and yet an extremely valuable undertaking. It is one of the major problems faced by every country in the world for it is the key to Mother Earth’s struggle for survival. Restoration pertains to the reestablishment and replenishment of natural wetland systems to be once more suitable for wetland creatures as their habitat. But, what wetland ecosystems are we pertaining to? What type of wetland ecosystem do we plan to target and why? Is it enough to establish any type of wetland ecosystem and be called â€Å"restoration†? As stated by Lovette (et al. , 2002), Australias enthusiasm for restoring and rehabilitating rivers and streams is growing at a fair rate yet most of the time, such projects fail to produce the desired results of improvement. This is due to the fact that these projects lack planning resulting to poorly defined project objectives and rehabilitation strategies. In addition to this matter, many social and political factors rather than a lack of technical skills were often major factors influencing the success of river restoration projects. Ecologists and restorationists took these questions in account and had included them as definitions of restoration and restoration-type activities. A simple yet very nifty definition of ecological restoration included in the 1992 report Restoration of Aquatics Ecosystems by the National Research Council (NRC), defined restoration as the â€Å"return of an ecosystem to a close approximation of its condition prior to disturbance.† The NRC declares that the concept of restoration to be further clarified by defining many types of restoration-related activities. Creation, reallocation, and enhancement are such activities that are similar to restoration, but vary in some aspect from rehabilitation of the original ecosystem to areas they once existed. Reintroduction of animals is also a major factor of restoration that must be taken in account.   The mere recreation of form without the specific function is not the essence of restoration, nor is having the function in the artificial pattern without even a close similitude to the real thing. The goal of restoration is to produce a natural, self-regulating ecosystem that functions perfectly with the landscape and conditions in which it occurs. Body   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   To have a deeper understanding in the field of ecological restoration, let us first define terms that are used in the field of ecological restoration.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Creation is defined as the construction of a wetland in an area that was not a wetland in the recent past (within the last 100-200 years) and that is isolated from existing wetlands (i.e., not directly adjacent) (Gwin, et al., 1999). In other words, creation occurs when a wetland is placed on the landscape by some human activity on a non-wetland site (Lewis, 1989). Normally, creation of a wetland in plot of land starts by digging out upland soils to an appropriate elevation suitable for the growth of wetland species by a proper hydrological pattern. Enhancement, as defined by Gwin, et al. (1999) is â€Å"the modification of specific structural features of an existing wetland to increase one or more functions based on management objectives, typically done by modifying site elevations or the proportion of open water. Although this term implies gain or improvement, a positive change in one wetland function may negatively affect other wetland functions. Enhancement may also be the alteration of a site to produce conditions that did not previously exist in order to accentuate one or more values of a site. For example, increasing the area of deep water by excavating parts of an emergent wetland may provide more duck habitat (the desired wetland value), but may decrease foraging and cover habitat for young fish (Lewis 1989). The term reallocation replacement pertains to altering or converting existing wetlands to create a different type of wetland. For example, transforming a developing wetland, like a swamp, to a pond will convert the habitat from one wetland type to a different type. A term commonly used during discussions of restoration is mitigation, which â€Å"refers to the restoration, creation, or enhancement of wetlands to compensate for permitted wetland losses (Lewis, 1989). It is stated in under Section 404 of the Clean Water Act that â€Å"wetlands may legally be destroyed, but their loss must be compensated for by the restoration, creation, or enhancement of other wetlands. Hypothetically, the policy aims retain the wetland’s quality. The Watershed Ecology Team if Wetlands, Oceans, and Watersheds have devised a list of principles which played a critical role to the success of a wide range of aquatic resource restoration programs and projects. These principles are applicable through the different stages in the process of wetland restoration and focus on scientific and technical issues. Nevertheless, in all environmental and ecological management activities, it is crucial to examine community perspectives and values. There are a lot of guiding principles that ecologists follow in the field of wetland and river restoration. Given below are some doctrines that may help in the restoration of the rivers in Western Australia, namely the Hutt, Greenough, and Chapman River. The common dilemma faced by these rivers is erosion of soil along their banks. This is due to the lack of vegetation to hold the soil in place. Because of this catastrophe, a number of the wild life, like birds nesting on the trees or the fishes in the river, is threatened to loose obtain damage to their habitat. The Chapman River Estuary, though a popular place, due to the lack of management, has degraded. Several erosions has occurred, weeds are numerous among the vegetation, and wildlife have been frequently disturbed. Restoration of these rivers considers several, yet not too costly stages. The first stage of the Greenough River Restoration Project cost approximately $11,000 while the second stage of the Greenough River Restoration Project needed a total funding of about $68,000 through Trust Funding. The Chapman River Foreshore Restoration Project at the Nanson Hamlet in Chapman Valley adhered principles which is slowly revitalizing the landscape, cost around $18,000. The purpose of the Hutt River Floodplain Management Plan (HRFMP) is to update the Advisory Committee on their status, investigations and implementation (ATAPATTU, 2001). A clear concept of the projects goals, objectives, performance, and desired outcome is a critical part in the success of the restoration project for it gives a vivid look on how the scheme should run. One principle, â€Å"Preserve and protect aquatic resources†, explains that existing ecosystems are critical in the conservation of biodiversity, and supply the weakened system with the necessary materials. Restoration, together with protection and preservation, can improve wetland systems in an immense level. In this principle, the first step to secure the revitalization of a system is to prevent further depletion (USEPA, 2006). According to Palmer (2005), five relevant features should be brought to mind during river restoration. They are a guiding image – by creating a vision of you goals and ideas, you have a concrete image of your desired outcome; improvement of ecosystems – by adding functionality to the factors in the ecosystem, you will have positive results that the environment supplies; increase in resilience – by generating flexible products that can recover when damaged, or surpass other products; doing no lasting harm – actions done in restoration should not give an ill effect to the surrounding countryside, and have a long-lasting positive effect on the target location; and completion of an ecological assessment – provide a written clearly defined results on the project (McGee, 2005). Restoration of natural structure and function plays a major role in the restoration of natural wetlands. In the recreation of a natural habitat, its structure must be deeply studied for if a flaw in the system occurs, the whole project could further damage the area or the surrounding terrain. The function should, as much as possible, be close to the existing system’s function to instill balance (USEPA, 2006). Conclusion and Recommendation   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Though there are quite a number of principles and guidelines that ecologists use in there quest to restore and revitalize denuded wetlands in the globe, these principles come together and express common guides to the success of rejuvenating the wetland system.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   The first step is to clearly plan the project focusing on critical points that will ensure the accomplishment of the activity. Next is to mobilize the design, in which requires funds, in a procedure that won’t disturb or harm the surrounding areas. It must be ensured that the outcome of the project will be, as much as possible, like the former wetland system, to avoid further damage to the environment rather than to revitalize the land. And lastly, there should be a constant maintenance and management in the area to preserve the beauty and functionality of the structured landscape.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   By following these few principles in the reconstruction of denuded wastelands, the future of the wetlands and rivers of Australia, and also the world, will be brighter. References USEPA.(2006). Definitions distinctions. Retrieved September 24, 2006, from River Corridor and Wetland Restoration Web site: http://www.epa.gov/owow/wetlands/restore/defs.html#Defs ______. (2002) Greenough. Retrieved September 24, 2006, from Westernbelle Australian Adventures Web site: http://www.westernbelle.com/gren.html ______. (2002) Hutt river province. Retrieved September 24, 2006, from Principality of hutt river.   Ã‚  Ã‚  Ã‚  Ã‚   Web site: http://www.westernbelle.com/H.HTML#huttriver Blacklow et. al, (2001). River restoration and management in australia: a national framework for vocational education and training and graduate studies.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006 Web site: http://www.rivers.gov.au/acrobat/uwa26/uwa26final.pdf#search=river%20restoration%20western%20australia McGee, T. (2005). Guiding principles for river restoration and sustainable product design. Retrieved September 25, 2006, from Treehugger Web site: http://www.treehugger.com/files/2005/04/guiding_princip.php ______. (2005). Evaluation sourcebook. Retrieved September 25, 2006, from Ecosystem Management Initiative Website:http://www.snre.umich.edu/ecomgt/pubs/wetlands/hennepin/2.4.PDF#search=river%20wetland%20restoration%20principles Peck, D. (2003). Resolution VIII.16 on wetland restoration.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006, from the Ramsar Convention on Wetlands   Ã‚  Ã‚  Ã‚  Ã‚   Web site:http://ramsar.org/res/key_res_viii_16_e.htm ______. 2002-2003 Australian government envirofund projects western australia.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006, from National Heritage Trust   Ã‚  Ã‚  Ã‚  Ã‚   Web site:http://www.nht.gov.au/envirofund/2002-2003/general/wa-projects.html Atapattu, D. (2001). Hutt river floodplain management plan (hrfmp): project leader’s report.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006, from the Regional Council Web site:http://www.gw.govt.nz/council-reports/pdfs/reportdocs/2001_110_1_Report.pdf#search=hutt%20river%20restoration%20project _____. 2001-2002 Coastcare projects: Western australia.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006, from National Heritage Trust   Ã‚  Ã‚  Ã‚  Ã‚   Web site:http://www.nht.gov.au/nht1/programs/coastcare/wa-01-02.html#45 ______. (2006). Fact sheet 9 planning for river restoration.   Ã‚  Ã‚  Ã‚  Ã‚   Retrieved September 25, 2006, from River Landscapes.   Ã‚  Ã‚  Ã‚  Ã‚   Web site:http://www.rivers.gov.au/manage/is9planning.htm

Metformin (Glucophage) Reactions

Metformin (Glucophage) Reactions Metformin (Glucophage) is available in the Pakistan since 1998. It falls in the same drug class as phenformin. Metformin is considered a first line agent and is significantly useful in people with known insulin resistance GLUCOPHAGE ® (metformin hydrochloride tablets) and GLUCOPHAGE ® XR (metformin hydrochloride extended-release tablets) are oral antihyperglycemic drugs used in the management of type 2 diabetes. Metformin hydrochloride (N,N-dimethylimidodicarbonimidic diamide hydrochloride) is not chemically or pharmacologically related to any other classes of oral antihyperglycemic agents. The structural formula is as shown: Glucophage (metformin hydrochloride tablets) Structural Formula Illustration Metformin hydrochloride is a white to off-white crystalline compound with a molecular formula of C4H11N5 †¢ HCl and a molecular weight of 165.63. Metformin improves hyperglycemia primarily through its suppression of hepatic glucose production, especially hepatic gluconeogenesis[1]. The average person with type 2 diabetes has three times the normal rate of gluconeogenesis; metformin treatment reduces this by over one third.[2] Metformin activates AMP-activated protein kinase (AMPK), a liver enzyme that plays an important role in insulin signaling, whole body energy balance, and the metabolism of glucose and fats;[3] activation of AMPK is required for metformins inhibitory effect on the production of glucose by liver cells.[4] Research published in 2008 further elucidated metformins mechanism of action, showing that activation of AMPK is required for an increase in the expression of SHP (Small heterodimer partner), which in turn inhibits the expression of the hepatic gluconeogenic genes PEPCK and Glc-6-Pase.[5] Metformin is frequently used in research along with AICAR as an AMPK agonist. The mechanism by which biguanides increas e the activity of AMPK remains uncertain; however, research suggests that metformin increases the amount of cytosolic AMP (as opposed to a change in total AMP or total AMP/ATP).[6] In addition to suppressing hepatic glucose production, metformin increases insulin sensitivity, enhances peripheral glucose uptake, decreases fatty acid oxidation, and decreases absorption of glucose from the gastrointestinal tract.[8] Increased peripheral utilization of glucose may be due to improved insulin binding to insulin receptors.[9] AMPK probably also plays a role, as metformin administration increases AMPK activity in skeletal muscle.[10] AMPK is known to cause GLUT4 translocation, resulting in insulin-independent glucose uptake. Some metabolic actions of metformin do appear to occur by AMPK-independent mechanisms; a recent study found that the metabolic actions of metformin in the heart muscle can occur independent of changes in AMPK activity and may be mediated by p38 MAPK- and PKC-dependent mechanisms.[11] Metformin causes a few gastrointestinal side effects including nausea, metallic taste, diarrhea and abdominal discomfort[7] . These can be avoided if the dose is increased slowly, and taking the drug with meals. A small amount of weight loss, possibly due to drop in net caloric intake due to appetite repression and/or a reduction in hyperinsulinemia is suggested. Falling in the same drug class as phenformin, the reported incidence of lactic acidosis is surprisingly low, 0.03 per 1000. In a US double-blind clinical study of GLUCOPHAGE in patients with type 2 diabetes, a total of 141 patients received GLUCOPHAGE therapy (up to 2550 mg per day) and 145 patients received placebo. Most Common Adverse Reactions (>5.0 Percent) in a Placebo-Controlled Clinical Study of GLUCOPHAGE Monotherapy The occurrence can further be avoided if contraindications are followed. It is contraindicated in people with a high risk of lactic acidosis: renal serum creatinine levels over 150 ÃŽ ¼mol/l[14}or hepatic impairment, respiratory insufficiency, severe infection and alcohol abuse. Any pharmacological therapy that alters either of the factors mentioned before is also considered. It should also be used cautiously in elderly especially those above 80 years of age. It is recommended to monitor renal function upon initiation and at least once a year thereafter. It should be withheld immediately before a person has a procedure with a radiocontrast dye, as the dye increases the risk of renal failure and therefore lactic acidosis [15] [16]. It should also be discontinued before and surgery and can be started immediately after if the renal function is normal and the patient is stable. It is also recommended to monitor hematological parameters as it alters vitamin B12 absorption [12] [13] and therefore cause anemia (7% in clinical trials). The mechanism of action is unknown but can be reversed by discontinuation of the drug. Daily dosage should be 500 mg orally twice daily with meals. The dose can be increased every 2 weeks to 2000 mg daily. References Kirpichnikov D, McFarlane SI, Sowers JR (2002). Metformin: an update. Ann Intern Med 137 (1): 25-33. PMID 12093242. Hundal R, Krssak M, Dufour S, Laurent D, Lebon V, Chandramouli V, Inzucchi S, Schumann W, Petersen K, Landau B, Shulman G (2000). Mechanism by which metformin reduces glucose production in type 2 diabetes (PDF). Diabetes 49 (12): 2063-9. doi:10.2337/diabetes.49.12.2063. PMID 11118008. Towler MC, Hardie DG (2007). AMP-activated protein kinase in metabolic control and insulin signaling. Circ Res 100 (3): 328-41. doi:10.1161/01.RES.0000256090.42690.05. PMID 17307971. Zhou G, Myers R, Li Y, Chen Y, Shen X, Fenyk-Melody J, Wu M, Ventre J, Doebber T, Fujii N, Musi N, Hirshman M, Goodyear L, Moller D (2001). Role of AMP-activated protein kinase in mechanism of metformin action. J Clin Invest 108 (8): 1167-74. doi:10.1172/JCI13505. PMID 11602624. Kim YD, Park KG, Lee YS, et al. (2008). Metformin inhibits hepatic gluconeogenesis through AMP-activated protein kinase-dependent regulation of the orphan nuclear receptor SHP. Diabetes 57 (2): 306-14. doi:10.2337/db07-0381. PMID 17909097. Zhang L, He H, Balschi JA (2007). Metformin and phenformin activate AMP-activated protein kinase in the heart by increasing cytosolic AMP concentration. Am J Physiol Heart Circ Physiol 293 (1): H457-66. doi:10.1152/ajpheart.00002.2007. PMID 17369473. Bolen S, Feldman L, Vassy J, et al (2007). Systematic review: comparative effectiveness and safety of oral medications for type 2 diabetes mellitus. Ann Intern Med 147 (6): 386-99. PMID 17638715. Royal Pharmaceutical Society of Great Britain and the British Medical Association. Chapter 6:Endocrine system—6.1.2.2 Biguanides, British National Formulary, 54. Bailey CJ, Turner RC (1996). Metformin. N Engl J Med 334 (9): 574-9. doi:10.1056/NEJM199602293340906. PMID 8569826. Musi N, Hirshman MF, Nygren J, et al. (2002). Metformin increases AMP-activated protein kinase activity in skeletal muscle of subjects with type 2 diabetes. Diabetes 51 (7): 2074-81. PMID 12086935. Saeedi R, Parsons HL, Wambolt RB, et al. (2008). Metabolic actions of metformin in the heart can occur by AMPK-independent mechanisms. Am J Physiol Heart Circ Physiol 294 (6): H2497-506. doi:10.1152/ajpheart.00873.2007. PMID 18375721 Andrà ¨s E, Noel E, Goichot B (2002). Metformin-associated vitamin B12 deficiency. Arch Intern Med 162 (19): 2251-2. doi:10.1001/archinte.162.19.2251-a. PMID 12390080. Gilligan M (2002). Metformin and vitamin B12 deficiency. Arch Intern Med 162 (4): 484-5. doi:10.1001/archinte.162.4.484. PMID 11863489 Jones G, Macklin J, Alexander W (2003). Contraindications to the use of metformin. BMJ 326 (7379): 4-5. doi:10.1136/bmj.326.7379.4. PMID 12511434 Weir J (March 19, 1999). Guidelines with Regard to Metformin-Induced Lactic Acidosis and X-ray Contrast Medium Agents. Royal College of Radiologists. Retrieved on 2007-10-26 through the Internet Archive. a b Thomsen HS, Morcos SK (2003). Contrast media and the kidney: European Society of Urogenital Radiology (ESUR) guidelines. Br J Radiol 76 (908): 513-8. doi:10.1259/bjr/26964464. PMID 12893691.  

Mobile Ad Hoc Networks MANET

Mobile Ad Hoc Networks MANET Abstract Mobile 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 t heir performances which are calculated on the basis of performance metrics used which are End to end delay, Network load and Throughput. Chapter 1: Introduction This 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 done 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 type: Short Message Mail File transfers Video Audio etc When 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 Thesis: This 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 parameters 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 pe rformance 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 Work The main objective of this work is to study the different routing protocols, which are developed for Mobile 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 1 To 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 2 To 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 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 3 Conducting an experiment and collecting the output data: This 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 4 Analyzing the output data and ending up with summary and the conclusion: The 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 Survey 2.1 Introduction This 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 Protocols: As 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 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 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 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 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 m odels 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 protocol s. 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 setup carried is represented in tables below: With 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 Work A 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 are: Infrastructure network: These networks are used where the topology 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 worldwide. 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 changes 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 Routing: Routing 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 manipulate 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 Determination: Routing 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 used 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) Switching: Apart 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 another 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 Networks An 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 medium 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 Networks: A 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, 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 are: Asymmetric Links Redundant Link Interference Dynamic Topology 2.7 Characteristics of MANETs There 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 consumption 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 Protocols A 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 should be done with less overhead and minimal bandwidth consumption for effective communication. 2.9 Applications of MANETs Applications 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 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 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 Protocols According to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categories: Table driven (proactive) Routing 2.10.1 Proactive (Table-Driven) Routing Protocols These 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 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 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 periodic ally to all one hop neighbours using hello messages. 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 Protocols These 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 identified. 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 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 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 are: Route 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 fields: Source address: the address of the node which originates the route request Source Sequence number: the current sequence number to be used in deciding the route for the source request Destination 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 fields Destination address: the address of the destination node for which the route is abounded Destination sequence number: the destination sequence number related to the route Source address: the address of the source node that originates the route request Lifetime: 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 fields: Unreachable 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 Mobile Ad Hoc Networks MANET Mobile Ad Hoc Networks MANET Abstract Mobile 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 t heir performances which are calculated on the basis of performance metrics used which are End to end delay, Network load and Throughput. Chapter 1: Introduction This 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 done 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 type: Short Message Mail File transfers Video Audio etc When 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 Thesis: This 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 parameters 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 pe rformance 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 Work The main objective of this work is to study the different routing protocols, which are developed for Mobile 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 1 To 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 2 To 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 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 3 Conducting an experiment and collecting the output data: This 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 4 Analyzing the output data and ending up with summary and the conclusion: The 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 Survey 2.1 Introduction This 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 Protocols: As 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 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 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 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 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 m odels 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 protocol s. 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 setup carried is represented in tables below: With 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 Work A 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 are: Infrastructure network: These networks are used where the topology 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 worldwide. 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 changes 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 Routing: Routing 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 manipulate 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 Determination: Routing 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 used 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) Switching: Apart 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 another 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 Networks An 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 medium 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 Networks: A 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, 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 are: Asymmetric Links Redundant Link Interference Dynamic Topology 2.7 Characteristics of MANETs There 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 consumption 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 Protocols A 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 should be done with less overhead and minimal bandwidth consumption for effective communication. 2.9 Applications of MANETs Applications 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 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 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 Protocols According to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categories: Table driven (proactive) Routing 2.10.1 Proactive (Table-Driven) Routing Protocols These 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 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 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 periodic ally to all one hop neighbours using hello messages. 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 Protocols These 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 identified. 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 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 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 are: Route 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 fields: Source address: the address of the node which originates the route request Source Sequence number: the current sequence number to be used in deciding the route for the source request Destination 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 fields Destination address: the address of the destination node for which the route is abounded Destination sequence number: the destination sequence number related to the route Source address: the address of the source node that originates the route request Lifetime: 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 fields: Unreachable 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