Aristotle’s Definition of Rhetoric

Aristotle defines the fine art of persuasion. A rhetorician pursues witnesses, contracts, and the like in his pursuit of presenting an argument. However, not all forms of persuasion are rhetoric in nature. It is through persuasion that many arguments are won or lost. Aristotle talks in depth about what is right and what is wrong. He has meticulously defined terms like good, goodwill, judge, judgment, and litigation that form a crucial part of any judicial process. The reason is, according to Aristotle, laws are made after long consideration. On the other hand, decisions in the courts are given at a short notice. This makes it hard for those who try to present an argument and win the case based on the decision of the lawgiver. It is important that the lawgiver does not get influenced by matters of friendship or hatred, and lose vision of the truth. This paper will outline Aristotle’s definition of rhetoric and identify the role rhetoric plays in the judicial process. Aristotle’s Definition of Rhetoric Aristotle equivalents rhetoric to a formal system of reasoning that strives to arrive at the truth by the exchange of logical arguments. Argument is the key to the art of persuasion. A rhetorician will be able to convince a person by persuasion. People use rhetoric â€Å"either at random or through practice and from acquired habit. † That is, while some speakers succeed to persuade through practice, others achieve it spontaneously. Aristotle closely relates rhetoric to dialectic. Both rhetoric and dialectic deal with arguments from accepted hypotheses. A rhetoric person can use dialectic tools in defense of his arguments. While dialectic is useful for arguments relating to private or academic matters, rhetoric is for arguments relating to public matters. This is because rhetoric considers that the opponents are intellectuals or persons who are familiar with the subject being argued about. Dialectic is concerned with general questions that apply to â€Å"untrained thinkers† (Rhetoric I. 2). In rhetoric, three things comprise an argument—first is the speaker (ethos), second is the listener (pathos), and the third is the argument itself (logos). (Rhetoric I. 2). First, the audience will give importance to an argument if the speaker is a trustworthy person. The speaker must display practical wisdom and should be able to reason logically. He or she should have an upright character and goodness in its various forms, and should possess the good will to understand emotions. Second, the emotional state of the audience is important in the interpretation of the argument. If the listener is in a good or bad mood, then the argument takes the shade of his mood. The speaker should be persuasive enough to motivate and arouse the right mood in the listener. Third, the speaker persuades by the argument itself. There are two types of arguments: induction and deduction. An inductive argument in rhetoric argues with an example. It takes a statement and shows other statements that are similar to it. A deductive argument in rhetoric is the enthymeme, which is an argument achieved by proof or demonstration. Speeches that rely on examples are persuasive in nature; however, those that rely on enthymemes induce applause from the audience. Determined by the class of listeners, rhetoric falls into three divisions. It is the listener who determines the objects of the speaker and the speech. The listener may either be a judge, who takes a decision of things past or future, or a mere observer. A jury member decides on future events and the man who waits on the jury decides on past events. Observers are people who merely decide based upon the orator’s skill. From this idea branches the three divisions of oratory—political, forensic, and the ceremonial oratory of display. A good orator must have the appropriate prepositions at his commands. The prepositions of rhetoric are complete proofs, probabilities, and signs. According to Alain Lempereur, â€Å"today, it is necessary to circumscribe the respective fields of logic and rhetoric in the language of law, while showing how they are sometimes complementary in the resolution of legal problems. † The Role of Rhetoric in the Judicial Process Rhetoric is a faculty used for providing judgment. Every man should comply with the rules of the law, and the law varies with each form of government. Hence, one of the important qualifications for a good judge is that he or she should understand all forms of government, since the interest of men lies in the maintenance of the established order. According to Aristotle, the supreme right to judge always remains â€Å"with either a part or the whole of one or other of the(se) governing powers† (Rhetoric I. 8). So it is important that the judge should be a man of good intellect. The four forms of government are democracy, oligarchy, aristocracy, and tyranny. The ends of each of these governments vary. For example, â€Å"The end of democracy is freedom; of oligarchy, wealth; of aristocracy, the maintenance of education and national institutions; of tyranny, the protection of the tyrant† (Rhetoric 1. 8). Rhetorical persuasion is not only obtained by demonstrative but also by ethical argument. Hence it is important for a rhetorician to understand the moral qualities characteristic of each form of government. Since a legal verdict is a decision, it is particularly important for a political speaker to maintain integrity of his character in the interest of his audience. He should entertain the right feelings and he should, in turn, induce the right feelings in his audience. In delivering judgment, rhetoric seeks the use of ethos and pathos, in addition to logical proofs. John Rainold, in Oxford Lectures on Aristotle’s Rhetoric, states that as far as possible what is good or bad â€Å"must be settled by the ruling of the Lawgiver, since it is easier [to find] one man [of good sense capable of framing laws and pronouncing judgments] than many men. † Law is either special or general in nature. A special law is a written law, one that regulates the life of a particular community or the law of a state. A general law is an unwritten law, the principles that are supposed to be acknowledged everywhere or the universal law. Individuals or an entire community may affected by the law. A wrongdoer either understands and intends the action, or does it without an understanding. Aristotle defines that there are seven causes of human action that the law has to consider. They are involuntary actions like chance, nature, and compulsion, and voluntary actions like habit, reasoning, anger, and appetite. Aristotle describes accusation and defense in detail in Book I, Chapter 10 of Rhetoric. He describes that â€Å"wrong-doing† is an injury that one person voluntarily inflicts on another contrary to law. There are three things that a prosecutor should ascertain: â€Å"first, the nature and number of the incentives to wrong-doing; second, the state of mind of wrongdoers; third, the kind of persons who are wronged, and their condition† (Rhetoric I. 10). Judgment can happen in two senses—broad and narrow. In its broad sense, it involves decisions that one takes in everyday activities, wherever there is more than one possibility. In its narrow sense, it involves judgment taken in assemblies and law courts. Judging involves two people—the one who speaks and persuades, and the other who listens and judges. It also involves two mutually contradictory arguments that the judge has to listen and judge. A judge should be prudent in judging whether something is important or unimportant, or just or unjust. They should never take instructions from the petitioners and should decide for themselves. Aristotle emphasizes that â€Å"the whole business of rhetoric is with opinion† (Rhetoric, III. 1). Similarly, a litigant should show that the alleged fact is so or is not so and that it has happened or has not happened. The duty of argument is to challenge conclusive proofs. An argument in forensic oratory can be categorized as the fact, the amount of injury, the existence of injury, and the justification. An argument in ceremonial oratory is taken on the basis of trust and the speaker will maintain the nobility of the actions in question. An argument in political oratory presents if something is possible or impossible, just or unjust, good or bad as the orator thinks. The general lines of argument common to all oratory are: the possible and the impossible, past fact, future fact, and degree. The possible and impossible considers that any two contraries are equally possible. Aristotle says that â€Å"if a man can be cured, he can also fall ill; for any two contraries are equally possible, in so far as they are contraries† (Rhetoric, II. 19). Past fact argues that in two things, if one of the less likely things has happened, then there is a possibility that the more likely thing should also have happened. For example, if a man has forgotten a thing, then it is likely that he has once learnt it. Future fact considers that a thing will be done if there is the power and wish to do it. If the means to the end has happened, then the end will soon follow. For example, if there is a foundation, there will be a house. Degree considers the greatness and smallness of things. One has to apply prudence in judgment since there is also a flip side to rhetoric. People might use their persuasive skills in making the judge believe in what is wrong and they might use it for unjust reasons. Aristotle comforts by telling that it is easier to prove and believe in things that are true. And, every virtue has its negative side. It is left to the individual to either benefit by using them right or to inflict great injuries by using them wrong. References 1. Alain Lempereur, in his paper presented at the International Symposium â€Å"Argumentation, Logic and Cognition,† Ghent University, 6–8 December 1989. http://www.springerlink.com/content/qv8722r647546mv2/ 2. Stanford Encyclopedia of Philosophy, http://www.seop.leeds.ac.uk/entries/aristotle-rhetoric/ 3. John Rainold's Oxford Lectures on Aristotle's Rhetoric, by John Rainolds, Lawrence D. http://books.google.com/books?id=77RPL09TOTIC&pg=PA137&lpg=PA137&dq=aristotle's+rhetoric+in+the+judicial+process;source=web;ots=vDL0uMCFaz;sig=e9RjGNwjy64EDGfMrfSSvt9P-RU;hl=en;sa=X;oi=book_result;resnum=2;ct=result#PPA129,M1

Title : the Affects of Temperature on Enzymes Activity

Title : the affects of temperature on enzymes activity 1. The Problem: measuring and recording the digestion of carbohydrates by enzyme amylase 2. Independent variable: water bath temperature 3. Dependent variable: the time taken for the carbohydrates to get digested by amylases 4. Controls: the amounts of the carbohydrates and the enzymes in the reaction 5. Quantitative measurement: Time | Temperature | Enzymes concentration | Substrate concentration | Starches Indicators | Catalysts | In minutes | Cloven /Celeste | Per millimetre cube | Per millimetre cube | Per drop | No catalyst | 1.Materials: 6 water bathes. test tubes, test tube rack , amylase enzymes , carbohydrate form ( flower or ,potato), thermometers , indicator ,stop clock ,protection (lab coat, goggles ) 2. Procedure: * prepare 6 test tubes with 10 cm of carbohydrate milk and misuse 5 cm of amylase enzymes in a cringe and add to test tube also indicator should be add and there is no catalyst in this experiments * Place t he test tubes on the water baths Water baths should be with fixed temperatures from 10 ,20,30,40,50,60,70 * Start the stop clock as soon as the test tube in the water bath * Keep an eye on the test tube till colour change is observed and the take the test tube out and tack time measurements * Also every temperature measurements should be done individually that the other tests to eliminate error (no one can be in 6 places at the same time ) * Make a table and record the time taken to the enzymes to work and digest the substrate at each temperature individually *Draw a graph Make your conclusion based on the results Hypothesis:. the affect of temperatures on rate of typical enzyme –controlled reaction up to about 40c the rate increases smoothly, also a 10 degree increase of the temperature accompanied by approximate doubling in of the rate of the reaction this is the normal temperature rule of chemical reactions in general, above this temperature the rate starts to fall off the n decline rapidly . above 60 degree the rate ceases or stop completely. . Explanation: increase of reaction why? Increases in the temperature of a system results from increases in the kinetic energy of the system. This has several effects on the rates of reactions, 1-the increase in temperature will increase the activation energy of a molecules there for it has more potential to react and change status Also the temperature will make the molecules move faster and as a result more collision will be possible per/minute . Enzyme’s activity stops why? Altogether and that is because of the heat changes the shape of the enzyme molecules preventing them from working ,this is called (denaturation ) in fact enzymes will denature and any temperature that is why they cannot be used over and over again ,however the higher the temperature the less time it takes for the denaturation to occurs . 5. Risk assessmentHazard | Risk | How to avoid | What happens in case of accident | Risk probabil ity to occurs | Heat from hot water bath| Burning | Handel with care | Seek medical help| Big risk| Enzymes | Biological hazards (irritant | Handel with correct equipment | Wash under water tape | Medium | Glass equipment | Injury or a glass cute| Try to handel with care | Seek medical help | Big | Thermometer | In case it breaks contain mercury | Handle with care Don’t move it from the water bath unless by the lab specialist | Seek eargent medical help in case of contact with mercury | Big | Electrical wire from water baths | Electrocuted or starting a fire | But it out of the way not in contact with water | Seek medical help | Small | Source | Reference | Was it useful | Used for | Advanced biology | Michael Kent, 2004. Advanced Biology. Edition. Oxford University Press| yes| Background information | Biology – Principles and Processes| M B V Roberts, 1993. Biology: Principles and Processes Pb. Edition. Thomas Nelson. | Yes | Methods | Web | Effect of temperature on e nzyme activity. 2012. Effect of temperature on enzyme activity. [ONLINE] Available at: http://academic. brooklyn. cuny. edu/biology/bio4fv/page/enz_act. htm. [Accessed 13 November 2012]. | Yes | | | | | |

Geertz and Pacanowsky Cultural Approach to Organization Essay

Geertz and Pacanowsky Cultural Approach to Organization - Essay Example From the film ‘Developing Organizational Culture,’ Tom examines how the theory can be applied in promoting an organizational culture within a workplace. He says that culture needs to be inclusive. Meaning, it should not come from one dominant section, but be a blend that reflects the entire organization. He agrees that culture is not organization, itself, is a culture and does not necessarily need to have one. Also, he concurs that it is a unique and elusive system of shared meaning which should be embraced by everyone as it determines what the organization stands for. No organization is made up of one person. Their complexities and diversities dictate that they need to be favorable for all. In conclusion, Cultural Approach to Organization is a brilliant theory that, if effectively applied in management, can help in producing an ideal workplace. Geertz and Pacanowsky did a commendable by doing a great research that can help in producing an excellent workplace. Surely, no organization has a culture because it is the very organization which is a culture. At the same time, it needs to be drawn from the narratives from the personal, corporate and collegial stories. For all organizations to excel, they need to have a set of culture which defines their system. As seen in the article and film, its effective application can help in promoting effective interpersonal and organizational communication which can in turn help in creating harmony within the workplace. It shows that the theory can help a lot if properly applied.

Week 2 posts 6340 Assignment Example | Topics and Well Written Essays - 250 words

Week 2 posts 6340 - Assignment Example ver wonder who exactly the target audience is since you have mentioned the employees of McDonalds and also the customers and hence am a bit confused, please clarify about the target group and especially those that will be having free check-up of their blood pressure (Dougherty, 2011). Volunteering is not an easy task and especially when it has to do with teaching patients due to the differences in educational backgrounds and hence what you are doing is really honorable and I encourage you to continue and even recruit other nursing students to follow in that good cause (Scheetz, 2000). I also admire the electronic medical recording as I know how efficient it is and makes easier the work of especially nurses. Cancer is a killer disease and any helping hand extending towards furthering research about it and especially by a profession is highly appreciable. The participation by leadership is truly admirable cause. Kudos and continue with the same spirit to raise more funds not only for cancer but also other killer diseases as well which need more research (Pape, 2000). American Association of Colleges of Nursing. (1999). Defining scholarship for the discipline of nursing. Washington, DC: Author. Retrieved January 16, 2013, from: http://www.aacn.nche.edu/publications/position/defining-scholarship Pape, T. (2000). â€Å"Boyers model of scholarly nursing applied to professional development. Association of Operating Room Nurses.† AORN Journal, 71(5), 995-9, 1001-3. Retrieved from

Female gemital circumcision or mutillation Research Paper

Female gemital circumcision or mutillation - Research Paper Example The women are still subjugated and made docile in order to be the minions of men forever. This smacks of the wider agenda on the part of men in those countries to keep silent on the practice so that their supremacy is not threatened. Female genital mutilation is (FGM) a procedure forcibly practiced on girls for non-medical reasons mainly prompted by religious beliefs. This age-old practice has been under severe criticisms for the past more than two decades. It is a deliberate assault on the female body that is physically and psychologically damaging. In the era of human rights, the practice is highly barbaric and condemnable. This paper aims to make a systematic review of literature on the subject ranging from age-old practice, human rights violations to health ramifications. The review should rest with the latest status of the practice and conclude whether it has been completely eradicated, on the decline, on the increase instead or in the same old status and to ascertain what health authorities and human rights enforcement have achieved so far in containing the practice. Various practices include Sunna, Modified Sunna, Clitoridectomy/excision and the most extreme form of infibulations. In Sunna which means tradition in Arabic, prepuce of the clitoris is prickled, slit or removed In Modified Sunna, clitoris is either partially or totally excised. In Clitoridectomy or excision, clitoris is partly or entirely removed as also all parts or part of the labia minora. The extensive scar tissue as a result occludes vaginal opening. In the most extreme form called infibulation or pharoanic circumcision, clitoris is removed and labia minora is excised along with its inner layers (Lightfoot-Klein, 1989). The last of these procedures is followed by stitching of the raw edges with cat gut or even thorns to make the edges adhere together so as to form a scar issue as a bridge to cover the vaginal opening. And some stuff such as silver of wood

Describe three controversies that led to the distinctions between Essay

Describe three controversies that led to the distinctions between Orthodox and Western Christianity - Essay Example On the other hand, the bishop of Rome governed the western group implying its administration was under a single bishop. As a result, basic theological differences emerged between the eastern and the western Christians (Vidmar 47). Separation between the Roman Catholic Church rather the western Christianity and the Eastern Orthodox Christianity was primarily based on deviation by Rome from the seven ecumenical councils’ original conclusions. This included the universal papal supremacy claim. Similarly, â€Å"Filoque controversy† is noted as another contributing factor to the difference between the two religions. The insertion of the phrase into the Nicene Creed changed the implication of the Holy Spirit source. Rather than in the usual perception of its origin from the Father, the â€Å"Filogue† which meant from the son, changed the Creed to imply both the Father and the Son were the source of the Holy Spirit. Despite the western emphasis of Christ’s divinity, the Orthodox Christians were against the alterations and the emerging meaning after the insertion. According to the Eastern Christians, the Father defines the origin of both the Son and the Holy Spirit (Ware 56). The concept of â€Å"Sola Scripture† is another area that distinguishes the western Christianity from the Orthodox. According to the western Christians, the â€Å"Scripture alone† rather the â€Å"Sola Scripture† claim that God’s word can be clearly comprehended and construed by an individual believer. Therefore, it is sufficient to be defined as the final authority under the western Christianity; however, the Orthodox posits that the Holy Scripture in the Holy tradition are of equal importance and value. Their definition of the Holy Scripture stems from the definition and interpretation affirmed in the first seven ecumenical council’s teachings by the church. In addition, the difference in theological approaches explains the distinction that exists between the Western Christianity and

Appearance and Reality Essay Example | Topics and Well Written Essays - 1000 words

Appearance and Reality - Essay Example To start with, he considers light falling on the table and its distribution. He suggests that different people looking at the same table will actually see a different thing altogether depending on the angle of look and position with which they stand. He explains further that the two people will have different account of what they see, and the initial table will have a different â€Å"meaning† altogether. He continues by outlining other characteristics of the same and claims that the texture, when observed with the unaided eye, will be much different than when observed with microscopes of different powers. He alleges that more details will be revealed whenever the latter will be used, making him wonder of what more is yet to be found on this rather cool and smooth table. He elaborates that, if what can be perceived with the naked eye is questionable, then how true is that which can be observed with aids? Russell claims that a real shape will maintain its shape regardless of the angle with which it is looked at. He alleges that a circular shape will appear oval like when viewed from a distance and thus deviating from the initial theory of â€Å"real shapes,† hence concludes that there is no such thing as a real shape. Briefly, Russell Bertrand, an acclaimed theorist, suggests that there is no such thing as â€Å"Reality.† From the examples given, he brings out the possibility of reasoning and challenging even the most of basic things in life that we consider common sense. Physics teaches that light travels from the object to the eye, so whatever we perceive depends upon the light on the same object to our eyes. Therefore, whatever our eyes see depends on the property of light. Thereby we can justify that whatever our eyes see is the real object. Considering his example on texture, where he was torn in between on what exactly he was to take as the real feel for the same. He actually overlooks a lot in his reason for even considering the micros copic view as part of the â€Å"real† view. One thing he forgets to understand is that the microscopic view, whether in low or high power is actually giving the hidden structural arrangement and combination of grains, which are the building blocks for the table, which will otherwise not have been seen with the naked eye. This example is the equivalent of considering a house where the basic are bricks. When the bricks are analyzed on their own, they exhibit a different property, which the otherwise finished house will not have. Thus, the house cannot be described using such property. The human eyesight is limited to a number of things. His claim that shapes look different from a given point of view can also be challenged critically. Perspective angle causes shapes to appear different, but that does not mean that they really are. In my view, people will see whatever they want to see and interpret them in whatever manner they deem fit, making each person to have a different opin ion and account concerning what they perceive depending on their current physical and psychological condition. However, if the different people were given the same â€Å"viewing† ground and if they all had perfect eyesight, all of them would give the same answer and description of what they saw. Russell’s claim that two people will give different accounts when viewing the same from different places is actually true. Were the same people given

Project Appraisal & Finance Essay Example | Topics and Well Written Essays - 4500 words

Project Appraisal & Finance - Essay Example We have to clarify the two sets of key questions we are dealing with. The first answers the questions "what" investments are and "why" they are important for a business, whilst the second answers the question of "how" investments decisions are made. The second part of our paper elaborates and expands on some of the key concepts that we cover in the first part. In the process, we hope to acquire a deeper understanding of the principles, methods, and issues that have to be considered in investment decision-making. This paper will closely simulate the complex world of top management decision-making faced by any business on a daily basis, and where no single discipline - finance, production, corporate social responsibility, or general management - dominates. As we look at all the conceivable angles that any normal business looks at prior to the making of an investment decision, we can realise that just like in the real world, we need to make choices. Hopefully, our discussion will show that management decision-making is a complex task, that every decision made today can have far-reaching consequences, and that any professional manager who wants to be a worthy practitioner of the art and science of management must take his or her educational preparation, and eventually his or her responsibility as a manager very, very seriously. The ABC Mining plc Case For purposes of clarity in our understanding of the assumptions used in our discussions and the consequent calculations to arrive at our decisions, we summarise the key facts of the case. ABC Mining plc is investigating the possibility of purchasing an open-cast coal mine at a cost of 2.5 million which the government is selling as part of its privatisation programme. It would invest in and operate the mine for four years, after which it would clean it up and sell the assets. The Finance Director prepared the projected profit and loss accounts shown in Table 1, and in his report to the Board of Directors recommended that the company should not proceed as the profitability of the proposal is poor. The following are the questions that need to be answered: First, what could be considered as the most appropriate investment appraisal methods which would help the company to decide whether or not to proceed with the project Second, explain why we consider the investment appraisal methods just discussed to be the most appropriate for evaluating investment projects. Third, we would discuss briefly whether the project should go ahead. Table 1: ABC Mining plc Profit and Loss Statement (in millions) Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Comments Investments Purchase (2.5) Paid to government Equipment (12.5) Financed 10m debt at 12% Sale of Equipment 2.5 Year 5 sale of vehicles/eqpt Working capital (0.5) One-time investment Sunk costs (0.2) Included in Year 1 write-off Survey costs (0.4) Counted in Year 1 Clean-up (0.4) Net vehicle sales 2.1 Sales 9.4 9.8 8.5 6.3 Less: Direct Exp Wages (2.3) (2.5) (2.6) (1.8) Incl.

The Role & Impact of Treatment for Individuals with Substance Use Research Paper

The Role & Impact of Treatment for Individuals with Substance Use Disorders - Research Paper Example rious activities including research and trends with the purpose of significantly improving â€Å"prevention and treatment and to inform policy as it relates to drug abuse and addiction† (National Institute on Drug Abuse, n.d.). The â€Å"Results from the 2010 National Survey on Drug Use and Health† for instance revealed that â€Å"in 2010, 4.1 million persons aged 12 or older (1.6 percent of the population) received treatment for a problem related to the use of alcohol or illicit drugs† (Substance Abuse and Mental Health Services Administration (SAMHSA): Past Year Treatment, 2011, par. 3). In this regard, the current research aims to proffer pertinent issues relative to the role and impact of treatment on individuals with substance use disorders (SUDs), particularly with cocaine, heroin and prescription drugs, or those classified under illicit drugs. The discourse would initially provide the definition for SUDs, prior to delving into the role and impact of treatm ent, as required. â€Å"Substance abuse is defined as a maladaptive pattern of substance use leading to clinically significant impairment or distress as manifested by one (or more) of the following, occurring within a 12-month period: Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home (such as repeated absences or poor work performance related to substance use; substance-related absences, suspensions, or expulsions from school; or neglect of children or household). Continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance (for example, arguments with spouse about consequences of intoxication and physical fights)† (American Psychiatric Association, 1994, p. 181). Treatment of SUDs would therefore depend on various factors: the type of substance or drugs used, the length of time these substances or drugs have been continuously used, the state or mental condition of

Teaching grammar in context Essay Example for Free

Teaching grammar in context Essay According to Constance Weaver’s book entitled Teaching Grammar in Context, this particular aspect of education helps the students used their language in a correct manner of putting phrases and thoughts together to create a single message that sends a rightful idea to the readers or the listeners of the message. This I the primary reason why teaching grammar is encourages to be within the context of teaching speech and writing practices to the students. This is to primarily allow the students to use in actual practice what they are learning regarding grammar through writing and speaking as well. Knowing the basic ideas regarding the facts about what process writing and teaching grammar in context means, elaborating the ideas that pertain to this particular discussion indeed helps in enriching the discussion presented herein. Through the utilization of the ideas of other writers in this particular matter, proving the fact that teaching grammar in context within the curriculum of teaching the processes of writing is a more effective approach in t4eaching language to students of all ages. Presentation of sources As mentioned earlier, the book entitled â€Å"Teaching grammar in context† as authored by Constance Weaver discusses the most basic ideas that pertain to the fact that the effects of teaching grammar and process writing in an integrated manner gives better results among students, especially in the manner that they try to apply their learned strategies of writing in an effective manner that they are able to send the ample and actual message that they want to sent to their readers. In this particular reading material, Weaver points out several important points of consideration that would indeed help in the process of integrating grammar lessons within the procedures of teaching writing skills to students. The said points are as follows: teaching concepts of subject, verb, clause, sentence, and related editing concepts When teaching the basic skills that are needed to be considered in writing, the lessons on verbs as well as subjects and other parts of speech would indeed help in the procedures of helping the student understand the importance of using the right words and right phrases to be able to send the actual message needed to be conveyed to the readers. teaching style through sentence combining and generating When editing processes are discussed, the sentence structure discussion could also be generated to help the students identify what particular parts of the written work needs to be revised so as to be able to send the correct ideas to the reading audience. teaching sentence sense and style through manipulation of syntactic elements Syntactic elements and being able to understand the importance of this particular aspect of grammar in creating sensible sentences helps the writers create a better piece of work with a much clarified message and a much more furnished work. teaching the power of dialects and dialects of power The correct usage of language helps in creating a more clarified message within the context of any written work. Being able to learn this particular power of language shall encourage students, or writers at that in careful choosing the words that they use in their writing as well as furnishing the grammar that they utilize in their writing procedures. Teaching punctuation and mechanics for convention, clarity, and style- the impact of learning how to clarify the messages through the effective use of punctuations and clarifying styles of writing shall indeed help writers in being able to understand the importance of sending clarified ideas through the enhancement of the usage of correct punctuations within sentences to denote impact and feelings of the writers towards the topic.

Internet Protocol Version 6 (IPv6) Analysis

Internet Protocol Version 6 (IPv6) Analysis Overview Internet Protocol version 6 (IPv6) is the next generation of protocol defined by InternetEngineering Task force (IETF) to replace the exiting IPv4 protocol. At present, the majority of Internet users are still using IPv4 protocol, and given that most of current networking applications and network equipment run in IPv4 environments, the migration from IPv4 to IPv6 cant be accomplished overnight. It is predictable that the migration will be a long-term process (it is forecasted that the process will take 10 20 years). During the migration, IPv4 and IPv6 will coexist in a same network. This migration process poses new challenges on the routers that are the core equipment in IP network. Traditional routers cant accommodate new future network with IPv4/v6 coexistence. The routers must be improved and upgraded so that they can support both IPv4 and IPv6.Given that the core router is very important and carries huge Internet traffics, it must be able to support IPv6 forwarding at wire rate. It means ASIC chip, but not software is used to support IPv6 packet processing. At the same time, it is very important that this support cant sacrifice any IPv4 performance. After all, most of current traffics is IPv4. The core router must expand to support IPv6 routing tables and needs to support IPv6 routing protocols, such as BGP4+, OSPFv3, ISISv6, RIPng and etc. It needs to support some migration strategy from IPv4 to IPv6, such as Tunnel, Dual Stack, Translation and etc. Same as many network technologies, successful deployment of IPv6 relies on the deployment of the operators IPv6 network. As one core component in IPv6 network, IPv6 core router is key to network building, applications, performance and stability. At present, mainstream router vendors like Cisco and Juniper announce that their routers can support IPv6 while some traditional IT equipment manufactures, especially those in Japan, think Internet upgrade caused by IPv6 will change the whole landscape of router market, which brings significant opportunities for them to enter router market. From 2000 to 2002, Hitachi, NEC and Fujitsu announced IPv6-capable core router to gain some market share in new Internet network. It must be admitted that IPv6 is still in the initial phase at present, which is reflected in the following aspects: most IPv6 network is in trial phase, the number of access users is low, carried IPv6 traffics cant be comparable to IPv4, the interoperability between IPv6 equipment still needs to be proved, and network engineers lack in experience in large-scale deployment and operation of IPv6 network. The lack of data and experience is one of important causes that make some operators lack in confidence in IPv6 network deployment. Many operators take wait-and-see attitudes. In order to prove IPv6 router (especially IPv6 core router), the support to IPv6, how are they performed and interoperated, provide a practical data basis for the operators to deploy IPv6 network and provide a reference for equipment manufactures to evaluate and improve their equipment, BII(Beijing Internet Institute) collaborate with 6TNet (IPv6 Telecom Trial Network) in China tested IPv6 core routers from 4 ven dors (Fujitsu, Hitachi, Juniper and NEC) in Beijing from October to December 2002. BII performed protocol conformance, performance and  interoperability tests. In these tests, we used the test instruments provided by Agilent and received strong technical support from Agilent. The test is not a comparative performance test in different router vendors. The purpose is to verify the feasibility of IPv6 deployment. With this test, the test team thinks that all SUT (system under test) has the ability to support commercial IPv6 network and provide basic IPv6 capabilities. They can support IPv6 routing protocols, support the forwarding of IPv6 datagram at wire rate and provide interoperability between them. From perspectives of pure technology, the test team thinks the products have been ready to deploy basic IPv6 core network.. Brief Descriptions of Test The requirements for hardware provided by the SUT (system under test) are as follows: IPv6-capable core router OC48 SM ports (both ports must be in different boards) Supports both FE ports and GE ports. The number of FE ports and GE ports is no less than 3 Finally, all vendors basically meet those requirements, although CX5210 provided by NEC doesnt support FE during the time of testing. The requirement for IPv6 capabilities provided by the SUT (system under test) include: support of IPv6 forwarding in hardware and support of related IPv6 routing protocols and migration strategy. Finally, all vendors meet our requirements as shown in the following table. Company IPv6 hardwareDual Stack RIPng OSPFv3 BGP4+ IPv6 over IPv4 forwarding Tunnel Fujitsu 9 9 9 9 9 9 Hitachi 9 9 9 9 9 9 Juniper 9 9 9 9 9 9 NEC 9 9 9 9 9 9 The SUT (system under test) models and OS versions are shown in the following table. Company Model Version Fujitsu Geostream R920 E10V02L03C44 Hitachi GR2000-20H S-9181-61 07-01 [ROUTE-OS6] Juniper M20 5.5R1.2 NEC CX5210 02.0(2e) 45.08.00 The test instruments we used in the test are as follows: Agilent Router Tester 900 Version: Router Tester 5.1,Build 11.15. Agilent QA Robot Version: Router Tester 5.3,Build 5.2 The IPv6 core router test is composed of three parts: Protocol conformance test, interoperability test and IPv6 performance test. Basic IPv6 Protocols and RIPng Basic IPv6 protocols include IPv6 Specification (RFC2460), ICMPv6 (RFC2463), Neighbor Discovery (RFC2461), Stateless Autoconfiguration (RFC2462), Path MTU Discovery (RFC1981), IPv6 address Architecture (RFC1884) and etc., which are basic capabilities provided by an IPv6 implementation. RIPng is defined by RFC2080 and is the extension and expansion of RIPv2. Its basic capabilities are same as RIPv2. The routing information exchanged by RIPng can carry IPv6 addresses and prefixes. RIPng runs on IPv6 network, uses multicasting address ff02::9 as destination to transfer routing information. RIPng is not compatible with RIPv2. RIP protocol is typically used in small networks and is not deployed in large networks because of its scalability and performance, which is same in IPv6 networks. The test does not include basic IPv6 protocols and RIPng because we think both capabilities are most basic and most preliminary capabilities that should be provided in an IPv6 router, these capabilities are implemented and interoperated very well in the routers from 4 vendors, and the 4 tested routers have been tested publicly or non-publicly several times in different occasions and provided good data. Therefore, we think it is unnecessary to make efforts to repeat these work and we skipped this test and focused on more challenged test items. BGP4+ Protocol Conformance Test At present, the external gateway protocol used in the IPv4 network is BGP4. Its basic protocols are defined in RFC1771. In order to carry IPv6 network information in BGP4 updates, IETF has defined a special property multi-protocol BGP (MP-BGP), also called IPv6 NLRI (Network Layer Reachability Information) to exchange IPv6 routing information, which is not a new version of BGP protocol, but an extension to BGP4. The extension is generally called BGP4+, which is compatible with BGP4. Refer to RFC2545 for its definition. Test Purpose and Used Standards: Purpose: To test the implementation of BGP4+ and conform with related standards for SUT (System Under Test). The following standards are referred in the test: Bates, T., Chandra, R., Katz, D. and Y. Rekhter, â€Å"Multiprotocol Extension for BGP-4†, RFC 2858, Jne 2000. Bates, T., Chandra, R., Chen, E., â€Å"BGP Route Reflection An Alternative to Full Mesh IBGP†, RFC2796, April 2000. Chandra, R. and J.Scudder, â€Å"Capabilities Advertisement with BGP-4†, RFC 2842, May 2000. Dupont, F. and P. Marques, â€Å"Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing†, RFC 2545, March 1999. Rekhter, Y. and T. Li, â€Å"A Border Gateway Protocol 4 (BGP-4) †. Traina, P., McPherson, D., Scudder, J., â€Å"Autonomous System Confederations for BGP†, RFC3065, February 2001. Test Methods: All the tests are based on topology emulation. One test port of instrument firstly establishes network topology emulation, then executes pre-written scripts, interacts with the port of SUT, performs related BGP4+ protocol tests individually and each test generates Passed/Failed record. The tests can be divided into active tests and passive tests. Active test means the tester is used to verify the state machine of SUT and the correctness of message format while passive test means the tester is used to interfere with SUT using messages with errors. Test Topology Test instrument and SUT use two independent Fast Ethernet or Gigabit Ethernet connections. All BGP4+ runs on the Fast Ethernet or Gigabit Ethernet connections. The physical topology is as follows: The logical topology is as follows: Test Items and Descriptions of Test Results: The BGP4+ protocol conformance test involves in the BGP multi-protocol extension, setup and transfer of BGP4+ IBGP and EBGP sessions, ability to receive IPv6 route updates, BGP4+ next hop, starting point, MED, local preference, AS_PATH, atom aggregation, community name and various properties, the ability of SUT to correctly process these properties, BGP4+ route reflector capability, BGP4+ federation capability. These tests can only ensure implementation of BGP4+protocol in SUT comply with the standard defined by RFC, and cant ensure SUT fully and successfully deploy BGP4+ routes in commercial IPv6 network. The following diagram briefly describes the test results. Attached table 1 includes all test items, description and detailed results of BGP4+ conformance tests for 4 routers. The test items and descriptions are extracted from RFC2858, RFC2545, RFC2842, RFC2796, RFC3065 and draft-ietf-idr-bgp4-14.txt part. Model Failed test items Fujitsu GeoStream R920 2 Hitachi GR2000-20H 5 Juniper M20 1 NEC CX5210 3 Analysis of Test Results: Capabilities not supported Confederation Route reflector, Community Fujitsus GeoStreamR920 of current version does not support BGP4+ federation capability. In all BGP4+ test items it supported, the general performance is fairly good. What needs to be improved is only one item that is to support the migration of undefined property and handle interim duration. It is hoped to improve null interface which cant support next hop at present. Hitachis GR2000-20H of current version supports all test items, and is only product fully supporting BGP4+ protocols in the core routers from 3 Japanese companies. However, it needs to be improved in the following areas: handling next-hop property of IBGP in BGP4+ protocol, using AS_PATH properties to prevent from route loop, the ability of route reflector to detect ORIGINATOR_ID. At the same time, we found in the interoperability test that GR2000-20H cant establish non-physical direct-connection sessions with IBGP peering entities, which Hitachi needs to improve. It is hoped to add loopback address capability. Junipers M20 passes all tests except one item excellently. NECs CX5210 of current version doesnt support BGP4+ route reflector and community properties. In all BGP4+ test items it supported, the general performance is fairly good. However, it needs to be improved in handling BGP4+ federation AS_CONFED_SEQUENCE property. It is hoped to add null interface configuration. Interoperability Test As above mentioned, IPv6 is in initial phase of commercial deployment at present. A large amount of IPv6-capable network equipments and terminals are available. IPv6 network built by the operators doesnt only use the equipment provided by a vendor. In multi-vendor network environment, the interoperability between equipment is vital. The interoperability test is composed of BGP4+ interoperability test and OSPFv3 interoperability test. It should be noted that specific items in the interoperability test only cover some most common properties of BGP4+ and OSPFv3, and are not the interoperability tests of all properties of BGP4+ and OSPFv3. BGP4+ Interoperability Establish IBGP Sessions Test Descriptions: The test is to verify GR2000-20H, CX5210, R920,M20 and fully meshed iBGP connections that can be established. Reference: RFC1771, RFC2545 and RFC2858. Test steps: GR2000-20H, CX5210, R920, M20 and SUT are connected as shown in the following diagram. 4 routers are in a same autonomous domain and are interconnected using IBGP protocol to form a full-meshed IBGP connection. Test instrument and SUT are interconnected using EBGP connection. Because GR2000-20H doesnt support IBGP across-router Session connection, we use a FE link to connect GR2000-20H to M20 to form a fully-meshed connection. Test Results: We verified whether iBGP sessions were established between GR2000-20H, CX5210, R920 and M20, and it was found all connections were set up successfully. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A EBGP- Route Advertisement Test Descriptions: To verify GR2000-20H, CX5210, R920 and M20 can advertise routes properly in a fully meshed networks. References: RFC1771, RFC2545 and RFC2858. Test steps: Establish network topology according to previous test, establish eBGP connection between tester and SUT, send 100 EBGP routes from tester to SUT. Results: We verified whether GR2000-20H, CX5210 and R920 and M20 routing tables were correct, and it was found all routing tables were correct. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A Establish EBGP Sessions Test Descriptions: The test is to verify GR2000-20H, CX5210, R920 and M20 can establish a fully meshed eBGP connections. Reference: RFC1771, RFC2545 and RFC2858. Test steps: GR2000-20H, CX5210, R920 and M20 are connected as shown in the following diagram. Test Descriptions: We verified whether EBGP sessions were established between GR2000-20H, CX5210, R920 and M20, and it was found all connections were established successfully. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A EBGP Route Advertisement Test Descriptions: To verify GR2000-20H, CX5210, R920 and M20 can advertise EBGP routes properly. References: RFC1771, RFC2545 and RFC2858. Test steps: Establish network topology according to previous tests, send routes from each router to all other routers. Test Results: We verified whether GR2000-20H, CX5210 and R920 and M20 routing tables were correct, and it was found all routing tables were correct. GR2000-20H CX5210 R920, M20r GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A OSPFv3 Interoperability OSPF protocols supporting IPv6 is OSPFv3. OSPFv3 routing mechanism is basically same as OSPFv2. However, OSPFv2 relies primarily on IPv4, while OSPFv3 makes many improvements in OSPFv2 and is not a simple extension, thus OSPFv3, whose corresponding protocol is RFC2740, runs on IPv6. For real world applications, many operators regard OSPFv3 as a brand new protocol, also its stability and maturity need to be further verified, so when IPv6 routing protocols are selected, it tends to use IS-ISv6 (draft-ietf-isis-ipv6-02.txt), which is only a simple extension to IS-ISv4 (RFC1195) (2 TLVs re-defined) and does not make changes fully. However, it is sure the opinion is not authoritative and need to be proved. Because of the limitations of test instrument, It is required for SUT to provide 100M Ethernet interface. As CX5210 does not support Ethernet interface at present, just M20, R920 and GR2000-20H were involved in the testing. However, it does not imply that CX5210 cant interoperate with other 3 routers and has any problems with functions implementation. In the test, GR2000-20H is called SUT1 in short, M20 is called SUT2, and R920 is called SUT3. Establish OSPF Connections DR Election Test Descriptions: In the initial status, set different OSPF priority levels for SUT1, SUT2, SUT3 and the test instrument (10, 8, 5, 0). Connect these equipments based on the network topology below. Verify SUT1, SUT2, SUT3 and test instrument to establish OSPFv3 adjacency and vote DR/BDR. After DR/BDR is established properly, put DR off the network, and check whether DR/BDR is established properly. Put off-net equipment on the network, and check whether DR/BDR is established properly. Change OSPF initialization priorities of SUT1, SUT2, SUT3 and test instrument, and implement new test from step 2. Repeat the tests for 4 times, and ensure each SUT and test instrument have one opportunity to be selected as DR and BDR under the intial status. During the test, all SUTs are in the same OSPF Area 0. Reference: RFC2740 Test Results: During the testing, all the OSPF adjacencys can be established between SUTs and DR, also BDR can be elected properly. After DR is off-line, BDR can be re-elected as DR and the one with sub-top priority will be BDR. When off-line equipment is on-line again, no re-electing process occurs. All test results comply with the requirements in related standards. Exchange LSA Database Test Descriptions: Test instrument simulates an internal network with 4 routers connected, and sends the routing information to SUT. Then verify the routing information received by SUT DR from test instruments will be sent to DR Other correctly. Same as the previous test item, firstly SUT1 is used as DR, then SUT2, and finally SUT3. Reference: RFC2740 Test Results: During the testing, OSPF adjacency can be established properly between all SUTs. DR receive LSA information from test instrument and properly send the information to DR Other, which can also receive and process LSA information properly. IPv6 Performance Test The major approach used for the performance testing was to send the IPv6 traffic with different packet sizes and specific QoS information, via SUT to the destination, and then by the tester measure the throughput, latency and packet loss of SUT in various topologies. For the IPv6 performance test, there are four vendors high-end IPv6 routers, with OC-48 POS ports on which throughput and latency will be measured, with IPv6 packet sizes of 64 bytes, 128bytes, 256 bytes, 512 bytes, 1024 bytes, 1480 bytes and 1500 bytes. The performance in various of circumstances were measured, including IPv4/IPv6 mixed traffics (IPv4 and IPv6 traffics with different ratio), IPv6 traffic with packet sizes mixtures, Sweep Packet Sizes. Also the maximum routing table entry supported and the performance on manually configured tunnels were verified. Most of the referred standards is extracted from RFC2544. At present, there are deficient applications for IPv6, and the number of users in the IPv6 network can not be compared to IPv4. The sum of maximum IPv6 of IX(Internet eXchage) traffics is less than dozens of Mbits/s. These traffics can be handled using a router refitted from a PC. Based on the circumstance, is it necessary to test the performance of OC48 ports ? Actually when the operators build IPv6 network and purchase IPv6 routers, todays IPv6 network is not under their consideration. Their networks should be able to deal with the changes and growth of IPv6 network next 5 7 years. In this sense, it is necessary for IPv6 core router to support the IPv6 traffic forwarding capacities at wire rate. Otherwise, what differences can be made between a real IPv6 router and a router refitted from a PC with installed BSD and Zebra ? The measurement of the number of routing table entry also meets the same situations. At present, therere around 300-400 entries in the IPv6 backbone router routing table, which cant compared to the huge number of IPv4 (110,000 ¼Ã‚ 130,000 routes). Secondly, IPv6 has drawn experience and lessons from IPv4 in design and address assignment. RIR only assigns the large block and fixed length IPv6 addresses to IPv6 operators, instead of the end users. To some extent, this can protect IPv6 routing tables from the explosive growth. The strict prefix filtering mechanism was set on BGP4+ routers by most of IPv6 network administrators and the router only allows minor prefixes, such as /16, /24, /28, /32, /35 and etc. However, the experience of IPv4 teach us a lesson- â€Å"Money Talks!†. In the fiercely competitive ages, it is very difficult for operators to reject users requirements. Under the conditions that IPv6 doesnt solve the problems of Multi-homing completely, it is possible that the network operators are required to broadcast users network prefixes into global IPv6 routing tables in order to achieve Multi-homing applications. So far RIR has begun to assign /48 ad dress segment to IPv6 of IX independently, while it is suggested IX doesnt broadcast the addresses. Thirdly, in many IPv6 networks, there are at least two IPv6 addresses segments, from 6BONE(3ffe::/16) and RIR(2001::/16) respectively, and maybe more prefixes will appear in the future. Fourthly, RIR cant ensure IPV6 addresses assigned to IPv6 operators are from a continuous address block. Current assignment policy indicates that /32 addresses of IPv6 assigned to operators can be continuously extended to /29. If new addresses are further required, they must be assigned to discontinuous address blocks and result in the growth of the number of routing tables. To sum up, the test team suggests that the number of IPv6 routing tables supported by the router should be no less than that of IPv4 routing tables, since it is very difficult to estimate the increasing number of routing tables of IPv6 core network right now. In current IPv6 networks, commercial IPv6 network and IPv6 trial network (6BONE) are interlaced without a explicit boundary between them. A packet from commercial IPv6 network may go through many IPv6 trial network before arriving at another IPv6 network. The network administrators of many trial networks are not regarded as a â€Å"operators†, but a â€Å"players† It is pretty unstable of their networks, with routers reset very frequently. In the meantime, the networks advertise global IPv6 routes to all peers, making their own IPv6 network to implement transit. It causes the instability of current IPv6 of BGP routes, and thus it is required the capabilities of IPv6 routers cover the flapping and convergence properly, which should be included in this test, however due to limited test time frame, it is a pity the test team has to give up these tests. The network topology used for the performance test is shown as following: Ideally, the test topology should be as following, so that the packet forwarding capability of the routers in real-world network environment is shown completely. Send one traffic from a source port of the tester, via multiple ports of the router to the destination ports of tester, measure the performance of the router. However as the vendors cant provide enough OC48 ports, the test team can only perform the test by simply sending packets from one port and receiving packets form another port. In this sense, this test environment cant simulate completely the performance of the router in the real-world network environment. The Measurement of Throughput and Latency with Different IPv6 Packets Sizes at OC-48 POS port Test Descriptions: To test the maximum IPv6 packet forwarding rate of SUT with zero packet loss with different IPv6 packet sizes. Test Methods: Send IPv6 packets, via SUT to the destination ports of the tester, which measures the packet rate of SUT according to the received IPv6 packets. Set the initial offered load to 2%, and If no packet loss occurs, increase the offered load to 100% and repeat the test. If packet loss occurs, decrease the offered load to (100%+2%)/2=51%, repeat the test again†¦Ã¢â‚¬ ¦In a binary search manner, continue to increase or decrease the offered load in subsequent iterations until the difference in offered load between successful and failed tests is less than the resolution for the test. This is the zero-loss throughput rate. Traffic forwarding mode: full duplex. Offered Packet type: IPv6; Offered Packet size (bytes): 64 128 256 512 1024 1480 1500 Test duration of each packet type(s): 5 Bandwidth resolution (%): 0.1 Line BER tolerance (10^_): -10 The results are as follows: Sustainable Throughput of OC-48 POS Port 105.00% 100.00% 95.00% 90.00% 85.00% 80.00% 75.00% 70.00% 65.00% 60.00% 55.00% 50.00% 64 128 256 512 1024 1480 1500 bytes bytes bytes bytes bytes bytes bytes Test Packets Size Average Latency (us) at Variable Test Packets Size 100 90 80 70 60 50 40 30 20 10 0 Test Packets Size Hitachi NEC Fujistu Juniper Hitachi NEC Fujistu Juniper Note: About inherent latency of tester Before we perform tests, we must consider intrinsic latency of tester. The following table indicates inherent latency of tester for different test packet sizes when sending 100% offered load. Inherent latency of tester (100% offered load) Packet Size (bytes) 64 128 256 512 1024 1480 1500 Average Inherent 2.74 2.69 2.69 2.65 2.65 2.60 2.60 Latency (us) From the above, the inherent latency of tester under different packet sizes is about 2.7us. Compared to the tens of us of SUTs latency, there are not significant impacts on the test results. In addition, the impact of inherent latency is fair to these 4 SUTs. Forwarding Performance of IPv4/IPv6 Packets on OC48 Ports Test Descriptions: To verify the performance of SUT to forward IPv4/IPv6 packets in offered packets sizes. The test requires SUT to support IPv4/IPv6 dual protocol stacks. Test Methods: The tester sends IPv4 and IPv6 traffic simultaneously in full duplex configuration, via SUT to the destination port, measure the throughput and latency with various ratio of IPv4 and IPv6 traffic. Send traffic with 50% of IPv4 and 50% of IPv6 and 100% offered load first time. If packet loss occurs, decrease the offered load in 5% resolution until the difference in offered load between successful and failed tests is less than the resolution for the test. This is the zero-loss throughput rate. At the same time, measure the latency at maximum forwarding rate. Then change the ratio of IPv4 and IPv6 traffic to test again. Increase continuously the proportion of IPv6 traffic to simulate the change of traffic characteristics in the real-world network transition. Test Descriptions: Offered load (%): initial100% with 5% increment and final 0 Offered packet types: IPv6 Percentage of IPv4 and IPv6 traffic: 50:50—10:90 (IPv4:IPv6) Offered packet size (bytes): 62 512 1518 Test duration of each packet size(s): 5 The test results are as follows: Sustainable throughput of OC-48 POS port at packet size 64 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 64 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Sustainable throughput of OC-48 POS port at packet size 512 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 512 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Sustainable throughput of OC-48 POS port at packet size 1518 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 1518 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Average latency (us) at test packets size 64 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 64 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/6 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper Average latency (us) at test packets size 512 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 512 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper Average latency (us) at test packets size 1518 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 1518 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/60 30/70 20/80  Ã‚  Ã‚  Ã‚   10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper IPv6 over IPv4 Configured Tunneling Performance of OC-48 POS Port Test Description: Tunneling technology is an effective means to connect separate IPv6 networks via IPv4 backbone. This item is to verify the performance of SUT when SUT encapsulates IPv6 data packets into IPv4 payload and forwards the packets. Test Method: The tester sends IPv6 data packets to SUT, and configures an IPv6 over IPv4 tunnel between SUT and the tester. Thus after SUT receives pure IPv6 packets from the tester, it will encapsulate it into IPv4 packet payload, and send IPv6 packets to destination over IPv4 network. The tester analyzes the packets forwared by the SUT at receiving end, calculates the throughput of SUT for different sizes of packets under the IPv6 over IPv4 configured tunnel. Test Results: IPv6 packet size: 512 Destination address of sending IPv6 data packets: 3FFE:0:0:4::2/64 Bandwidth range of sending IPv6 tra Internet Protocol Version 6 (IPv6) Analysis Internet Protocol Version 6 (IPv6) Analysis Overview Internet Protocol version 6 (IPv6) is the next generation of protocol defined by InternetEngineering Task force (IETF) to replace the exiting IPv4 protocol. At present, the majority of Internet users are still using IPv4 protocol, and given that most of current networking applications and network equipment run in IPv4 environments, the migration from IPv4 to IPv6 cant be accomplished overnight. It is predictable that the migration will be a long-term process (it is forecasted that the process will take 10 20 years). During the migration, IPv4 and IPv6 will coexist in a same network. This migration process poses new challenges on the routers that are the core equipment in IP network. Traditional routers cant accommodate new future network with IPv4/v6 coexistence. The routers must be improved and upgraded so that they can support both IPv4 and IPv6.Given that the core router is very important and carries huge Internet traffics, it must be able to support IPv6 forwarding at wire rate. It means ASIC chip, but not software is used to support IPv6 packet processing. At the same time, it is very important that this support cant sacrifice any IPv4 performance. After all, most of current traffics is IPv4. The core router must expand to support IPv6 routing tables and needs to support IPv6 routing protocols, such as BGP4+, OSPFv3, ISISv6, RIPng and etc. It needs to support some migration strategy from IPv4 to IPv6, such as Tunnel, Dual Stack, Translation and etc. Same as many network technologies, successful deployment of IPv6 relies on the deployment of the operators IPv6 network. As one core component in IPv6 network, IPv6 core router is key to network building, applications, performance and stability. At present, mainstream router vendors like Cisco and Juniper announce that their routers can support IPv6 while some traditional IT equipment manufactures, especially those in Japan, think Internet upgrade caused by IPv6 will change the whole landscape of router market, which brings significant opportunities for them to enter router market. From 2000 to 2002, Hitachi, NEC and Fujitsu announced IPv6-capable core router to gain some market share in new Internet network. It must be admitted that IPv6 is still in the initial phase at present, which is reflected in the following aspects: most IPv6 network is in trial phase, the number of access users is low, carried IPv6 traffics cant be comparable to IPv4, the interoperability between IPv6 equipment still needs to be proved, and network engineers lack in experience in large-scale deployment and operation of IPv6 network. The lack of data and experience is one of important causes that make some operators lack in confidence in IPv6 network deployment. Many operators take wait-and-see attitudes. In order to prove IPv6 router (especially IPv6 core router), the support to IPv6, how are they performed and interoperated, provide a practical data basis for the operators to deploy IPv6 network and provide a reference for equipment manufactures to evaluate and improve their equipment, BII(Beijing Internet Institute) collaborate with 6TNet (IPv6 Telecom Trial Network) in China tested IPv6 core routers from 4 ven dors (Fujitsu, Hitachi, Juniper and NEC) in Beijing from October to December 2002. BII performed protocol conformance, performance and  interoperability tests. In these tests, we used the test instruments provided by Agilent and received strong technical support from Agilent. The test is not a comparative performance test in different router vendors. The purpose is to verify the feasibility of IPv6 deployment. With this test, the test team thinks that all SUT (system under test) has the ability to support commercial IPv6 network and provide basic IPv6 capabilities. They can support IPv6 routing protocols, support the forwarding of IPv6 datagram at wire rate and provide interoperability between them. From perspectives of pure technology, the test team thinks the products have been ready to deploy basic IPv6 core network.. Brief Descriptions of Test The requirements for hardware provided by the SUT (system under test) are as follows: IPv6-capable core router OC48 SM ports (both ports must be in different boards) Supports both FE ports and GE ports. The number of FE ports and GE ports is no less than 3 Finally, all vendors basically meet those requirements, although CX5210 provided by NEC doesnt support FE during the time of testing. The requirement for IPv6 capabilities provided by the SUT (system under test) include: support of IPv6 forwarding in hardware and support of related IPv6 routing protocols and migration strategy. Finally, all vendors meet our requirements as shown in the following table. Company IPv6 hardwareDual Stack RIPng OSPFv3 BGP4+ IPv6 over IPv4 forwarding Tunnel Fujitsu 9 9 9 9 9 9 Hitachi 9 9 9 9 9 9 Juniper 9 9 9 9 9 9 NEC 9 9 9 9 9 9 The SUT (system under test) models and OS versions are shown in the following table. Company Model Version Fujitsu Geostream R920 E10V02L03C44 Hitachi GR2000-20H S-9181-61 07-01 [ROUTE-OS6] Juniper M20 5.5R1.2 NEC CX5210 02.0(2e) 45.08.00 The test instruments we used in the test are as follows: Agilent Router Tester 900 Version: Router Tester 5.1,Build 11.15. Agilent QA Robot Version: Router Tester 5.3,Build 5.2 The IPv6 core router test is composed of three parts: Protocol conformance test, interoperability test and IPv6 performance test. Basic IPv6 Protocols and RIPng Basic IPv6 protocols include IPv6 Specification (RFC2460), ICMPv6 (RFC2463), Neighbor Discovery (RFC2461), Stateless Autoconfiguration (RFC2462), Path MTU Discovery (RFC1981), IPv6 address Architecture (RFC1884) and etc., which are basic capabilities provided by an IPv6 implementation. RIPng is defined by RFC2080 and is the extension and expansion of RIPv2. Its basic capabilities are same as RIPv2. The routing information exchanged by RIPng can carry IPv6 addresses and prefixes. RIPng runs on IPv6 network, uses multicasting address ff02::9 as destination to transfer routing information. RIPng is not compatible with RIPv2. RIP protocol is typically used in small networks and is not deployed in large networks because of its scalability and performance, which is same in IPv6 networks. The test does not include basic IPv6 protocols and RIPng because we think both capabilities are most basic and most preliminary capabilities that should be provided in an IPv6 router, these capabilities are implemented and interoperated very well in the routers from 4 vendors, and the 4 tested routers have been tested publicly or non-publicly several times in different occasions and provided good data. Therefore, we think it is unnecessary to make efforts to repeat these work and we skipped this test and focused on more challenged test items. BGP4+ Protocol Conformance Test At present, the external gateway protocol used in the IPv4 network is BGP4. Its basic protocols are defined in RFC1771. In order to carry IPv6 network information in BGP4 updates, IETF has defined a special property multi-protocol BGP (MP-BGP), also called IPv6 NLRI (Network Layer Reachability Information) to exchange IPv6 routing information, which is not a new version of BGP protocol, but an extension to BGP4. The extension is generally called BGP4+, which is compatible with BGP4. Refer to RFC2545 for its definition. Test Purpose and Used Standards: Purpose: To test the implementation of BGP4+ and conform with related standards for SUT (System Under Test). The following standards are referred in the test: Bates, T., Chandra, R., Katz, D. and Y. Rekhter, â€Å"Multiprotocol Extension for BGP-4†, RFC 2858, Jne 2000. Bates, T., Chandra, R., Chen, E., â€Å"BGP Route Reflection An Alternative to Full Mesh IBGP†, RFC2796, April 2000. Chandra, R. and J.Scudder, â€Å"Capabilities Advertisement with BGP-4†, RFC 2842, May 2000. Dupont, F. and P. Marques, â€Å"Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing†, RFC 2545, March 1999. Rekhter, Y. and T. Li, â€Å"A Border Gateway Protocol 4 (BGP-4) †. Traina, P., McPherson, D., Scudder, J., â€Å"Autonomous System Confederations for BGP†, RFC3065, February 2001. Test Methods: All the tests are based on topology emulation. One test port of instrument firstly establishes network topology emulation, then executes pre-written scripts, interacts with the port of SUT, performs related BGP4+ protocol tests individually and each test generates Passed/Failed record. The tests can be divided into active tests and passive tests. Active test means the tester is used to verify the state machine of SUT and the correctness of message format while passive test means the tester is used to interfere with SUT using messages with errors. Test Topology Test instrument and SUT use two independent Fast Ethernet or Gigabit Ethernet connections. All BGP4+ runs on the Fast Ethernet or Gigabit Ethernet connections. The physical topology is as follows: The logical topology is as follows: Test Items and Descriptions of Test Results: The BGP4+ protocol conformance test involves in the BGP multi-protocol extension, setup and transfer of BGP4+ IBGP and EBGP sessions, ability to receive IPv6 route updates, BGP4+ next hop, starting point, MED, local preference, AS_PATH, atom aggregation, community name and various properties, the ability of SUT to correctly process these properties, BGP4+ route reflector capability, BGP4+ federation capability. These tests can only ensure implementation of BGP4+protocol in SUT comply with the standard defined by RFC, and cant ensure SUT fully and successfully deploy BGP4+ routes in commercial IPv6 network. The following diagram briefly describes the test results. Attached table 1 includes all test items, description and detailed results of BGP4+ conformance tests for 4 routers. The test items and descriptions are extracted from RFC2858, RFC2545, RFC2842, RFC2796, RFC3065 and draft-ietf-idr-bgp4-14.txt part. Model Failed test items Fujitsu GeoStream R920 2 Hitachi GR2000-20H 5 Juniper M20 1 NEC CX5210 3 Analysis of Test Results: Capabilities not supported Confederation Route reflector, Community Fujitsus GeoStreamR920 of current version does not support BGP4+ federation capability. In all BGP4+ test items it supported, the general performance is fairly good. What needs to be improved is only one item that is to support the migration of undefined property and handle interim duration. It is hoped to improve null interface which cant support next hop at present. Hitachis GR2000-20H of current version supports all test items, and is only product fully supporting BGP4+ protocols in the core routers from 3 Japanese companies. However, it needs to be improved in the following areas: handling next-hop property of IBGP in BGP4+ protocol, using AS_PATH properties to prevent from route loop, the ability of route reflector to detect ORIGINATOR_ID. At the same time, we found in the interoperability test that GR2000-20H cant establish non-physical direct-connection sessions with IBGP peering entities, which Hitachi needs to improve. It is hoped to add loopback address capability. Junipers M20 passes all tests except one item excellently. NECs CX5210 of current version doesnt support BGP4+ route reflector and community properties. In all BGP4+ test items it supported, the general performance is fairly good. However, it needs to be improved in handling BGP4+ federation AS_CONFED_SEQUENCE property. It is hoped to add null interface configuration. Interoperability Test As above mentioned, IPv6 is in initial phase of commercial deployment at present. A large amount of IPv6-capable network equipments and terminals are available. IPv6 network built by the operators doesnt only use the equipment provided by a vendor. In multi-vendor network environment, the interoperability between equipment is vital. The interoperability test is composed of BGP4+ interoperability test and OSPFv3 interoperability test. It should be noted that specific items in the interoperability test only cover some most common properties of BGP4+ and OSPFv3, and are not the interoperability tests of all properties of BGP4+ and OSPFv3. BGP4+ Interoperability Establish IBGP Sessions Test Descriptions: The test is to verify GR2000-20H, CX5210, R920,M20 and fully meshed iBGP connections that can be established. Reference: RFC1771, RFC2545 and RFC2858. Test steps: GR2000-20H, CX5210, R920, M20 and SUT are connected as shown in the following diagram. 4 routers are in a same autonomous domain and are interconnected using IBGP protocol to form a full-meshed IBGP connection. Test instrument and SUT are interconnected using EBGP connection. Because GR2000-20H doesnt support IBGP across-router Session connection, we use a FE link to connect GR2000-20H to M20 to form a fully-meshed connection. Test Results: We verified whether iBGP sessions were established between GR2000-20H, CX5210, R920 and M20, and it was found all connections were set up successfully. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A EBGP- Route Advertisement Test Descriptions: To verify GR2000-20H, CX5210, R920 and M20 can advertise routes properly in a fully meshed networks. References: RFC1771, RFC2545 and RFC2858. Test steps: Establish network topology according to previous test, establish eBGP connection between tester and SUT, send 100 EBGP routes from tester to SUT. Results: We verified whether GR2000-20H, CX5210 and R920 and M20 routing tables were correct, and it was found all routing tables were correct. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A Establish EBGP Sessions Test Descriptions: The test is to verify GR2000-20H, CX5210, R920 and M20 can establish a fully meshed eBGP connections. Reference: RFC1771, RFC2545 and RFC2858. Test steps: GR2000-20H, CX5210, R920 and M20 are connected as shown in the following diagram. Test Descriptions: We verified whether EBGP sessions were established between GR2000-20H, CX5210, R920 and M20, and it was found all connections were established successfully. GR2000-20H CX5210 R920 M20 GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A EBGP Route Advertisement Test Descriptions: To verify GR2000-20H, CX5210, R920 and M20 can advertise EBGP routes properly. References: RFC1771, RFC2545 and RFC2858. Test steps: Establish network topology according to previous tests, send routes from each router to all other routers. Test Results: We verified whether GR2000-20H, CX5210 and R920 and M20 routing tables were correct, and it was found all routing tables were correct. GR2000-20H CX5210 R920, M20r GR2000-20H N/A OK OK OK CX5210 OK N/A OK OK R920 OK OK N/A OK M20 OK OK OK N/A OSPFv3 Interoperability OSPF protocols supporting IPv6 is OSPFv3. OSPFv3 routing mechanism is basically same as OSPFv2. However, OSPFv2 relies primarily on IPv4, while OSPFv3 makes many improvements in OSPFv2 and is not a simple extension, thus OSPFv3, whose corresponding protocol is RFC2740, runs on IPv6. For real world applications, many operators regard OSPFv3 as a brand new protocol, also its stability and maturity need to be further verified, so when IPv6 routing protocols are selected, it tends to use IS-ISv6 (draft-ietf-isis-ipv6-02.txt), which is only a simple extension to IS-ISv4 (RFC1195) (2 TLVs re-defined) and does not make changes fully. However, it is sure the opinion is not authoritative and need to be proved. Because of the limitations of test instrument, It is required for SUT to provide 100M Ethernet interface. As CX5210 does not support Ethernet interface at present, just M20, R920 and GR2000-20H were involved in the testing. However, it does not imply that CX5210 cant interoperate with other 3 routers and has any problems with functions implementation. In the test, GR2000-20H is called SUT1 in short, M20 is called SUT2, and R920 is called SUT3. Establish OSPF Connections DR Election Test Descriptions: In the initial status, set different OSPF priority levels for SUT1, SUT2, SUT3 and the test instrument (10, 8, 5, 0). Connect these equipments based on the network topology below. Verify SUT1, SUT2, SUT3 and test instrument to establish OSPFv3 adjacency and vote DR/BDR. After DR/BDR is established properly, put DR off the network, and check whether DR/BDR is established properly. Put off-net equipment on the network, and check whether DR/BDR is established properly. Change OSPF initialization priorities of SUT1, SUT2, SUT3 and test instrument, and implement new test from step 2. Repeat the tests for 4 times, and ensure each SUT and test instrument have one opportunity to be selected as DR and BDR under the intial status. During the test, all SUTs are in the same OSPF Area 0. Reference: RFC2740 Test Results: During the testing, all the OSPF adjacencys can be established between SUTs and DR, also BDR can be elected properly. After DR is off-line, BDR can be re-elected as DR and the one with sub-top priority will be BDR. When off-line equipment is on-line again, no re-electing process occurs. All test results comply with the requirements in related standards. Exchange LSA Database Test Descriptions: Test instrument simulates an internal network with 4 routers connected, and sends the routing information to SUT. Then verify the routing information received by SUT DR from test instruments will be sent to DR Other correctly. Same as the previous test item, firstly SUT1 is used as DR, then SUT2, and finally SUT3. Reference: RFC2740 Test Results: During the testing, OSPF adjacency can be established properly between all SUTs. DR receive LSA information from test instrument and properly send the information to DR Other, which can also receive and process LSA information properly. IPv6 Performance Test The major approach used for the performance testing was to send the IPv6 traffic with different packet sizes and specific QoS information, via SUT to the destination, and then by the tester measure the throughput, latency and packet loss of SUT in various topologies. For the IPv6 performance test, there are four vendors high-end IPv6 routers, with OC-48 POS ports on which throughput and latency will be measured, with IPv6 packet sizes of 64 bytes, 128bytes, 256 bytes, 512 bytes, 1024 bytes, 1480 bytes and 1500 bytes. The performance in various of circumstances were measured, including IPv4/IPv6 mixed traffics (IPv4 and IPv6 traffics with different ratio), IPv6 traffic with packet sizes mixtures, Sweep Packet Sizes. Also the maximum routing table entry supported and the performance on manually configured tunnels were verified. Most of the referred standards is extracted from RFC2544. At present, there are deficient applications for IPv6, and the number of users in the IPv6 network can not be compared to IPv4. The sum of maximum IPv6 of IX(Internet eXchage) traffics is less than dozens of Mbits/s. These traffics can be handled using a router refitted from a PC. Based on the circumstance, is it necessary to test the performance of OC48 ports ? Actually when the operators build IPv6 network and purchase IPv6 routers, todays IPv6 network is not under their consideration. Their networks should be able to deal with the changes and growth of IPv6 network next 5 7 years. In this sense, it is necessary for IPv6 core router to support the IPv6 traffic forwarding capacities at wire rate. Otherwise, what differences can be made between a real IPv6 router and a router refitted from a PC with installed BSD and Zebra ? The measurement of the number of routing table entry also meets the same situations. At present, therere around 300-400 entries in the IPv6 backbone router routing table, which cant compared to the huge number of IPv4 (110,000 ¼Ã‚ 130,000 routes). Secondly, IPv6 has drawn experience and lessons from IPv4 in design and address assignment. RIR only assigns the large block and fixed length IPv6 addresses to IPv6 operators, instead of the end users. To some extent, this can protect IPv6 routing tables from the explosive growth. The strict prefix filtering mechanism was set on BGP4+ routers by most of IPv6 network administrators and the router only allows minor prefixes, such as /16, /24, /28, /32, /35 and etc. However, the experience of IPv4 teach us a lesson- â€Å"Money Talks!†. In the fiercely competitive ages, it is very difficult for operators to reject users requirements. Under the conditions that IPv6 doesnt solve the problems of Multi-homing completely, it is possible that the network operators are required to broadcast users network prefixes into global IPv6 routing tables in order to achieve Multi-homing applications. So far RIR has begun to assign /48 ad dress segment to IPv6 of IX independently, while it is suggested IX doesnt broadcast the addresses. Thirdly, in many IPv6 networks, there are at least two IPv6 addresses segments, from 6BONE(3ffe::/16) and RIR(2001::/16) respectively, and maybe more prefixes will appear in the future. Fourthly, RIR cant ensure IPV6 addresses assigned to IPv6 operators are from a continuous address block. Current assignment policy indicates that /32 addresses of IPv6 assigned to operators can be continuously extended to /29. If new addresses are further required, they must be assigned to discontinuous address blocks and result in the growth of the number of routing tables. To sum up, the test team suggests that the number of IPv6 routing tables supported by the router should be no less than that of IPv4 routing tables, since it is very difficult to estimate the increasing number of routing tables of IPv6 core network right now. In current IPv6 networks, commercial IPv6 network and IPv6 trial network (6BONE) are interlaced without a explicit boundary between them. A packet from commercial IPv6 network may go through many IPv6 trial network before arriving at another IPv6 network. The network administrators of many trial networks are not regarded as a â€Å"operators†, but a â€Å"players† It is pretty unstable of their networks, with routers reset very frequently. In the meantime, the networks advertise global IPv6 routes to all peers, making their own IPv6 network to implement transit. It causes the instability of current IPv6 of BGP routes, and thus it is required the capabilities of IPv6 routers cover the flapping and convergence properly, which should be included in this test, however due to limited test time frame, it is a pity the test team has to give up these tests. The network topology used for the performance test is shown as following: Ideally, the test topology should be as following, so that the packet forwarding capability of the routers in real-world network environment is shown completely. Send one traffic from a source port of the tester, via multiple ports of the router to the destination ports of tester, measure the performance of the router. However as the vendors cant provide enough OC48 ports, the test team can only perform the test by simply sending packets from one port and receiving packets form another port. In this sense, this test environment cant simulate completely the performance of the router in the real-world network environment. The Measurement of Throughput and Latency with Different IPv6 Packets Sizes at OC-48 POS port Test Descriptions: To test the maximum IPv6 packet forwarding rate of SUT with zero packet loss with different IPv6 packet sizes. Test Methods: Send IPv6 packets, via SUT to the destination ports of the tester, which measures the packet rate of SUT according to the received IPv6 packets. Set the initial offered load to 2%, and If no packet loss occurs, increase the offered load to 100% and repeat the test. If packet loss occurs, decrease the offered load to (100%+2%)/2=51%, repeat the test again†¦Ã¢â‚¬ ¦In a binary search manner, continue to increase or decrease the offered load in subsequent iterations until the difference in offered load between successful and failed tests is less than the resolution for the test. This is the zero-loss throughput rate. Traffic forwarding mode: full duplex. Offered Packet type: IPv6; Offered Packet size (bytes): 64 128 256 512 1024 1480 1500 Test duration of each packet type(s): 5 Bandwidth resolution (%): 0.1 Line BER tolerance (10^_): -10 The results are as follows: Sustainable Throughput of OC-48 POS Port 105.00% 100.00% 95.00% 90.00% 85.00% 80.00% 75.00% 70.00% 65.00% 60.00% 55.00% 50.00% 64 128 256 512 1024 1480 1500 bytes bytes bytes bytes bytes bytes bytes Test Packets Size Average Latency (us) at Variable Test Packets Size 100 90 80 70 60 50 40 30 20 10 0 Test Packets Size Hitachi NEC Fujistu Juniper Hitachi NEC Fujistu Juniper Note: About inherent latency of tester Before we perform tests, we must consider intrinsic latency of tester. The following table indicates inherent latency of tester for different test packet sizes when sending 100% offered load. Inherent latency of tester (100% offered load) Packet Size (bytes) 64 128 256 512 1024 1480 1500 Average Inherent 2.74 2.69 2.69 2.65 2.65 2.60 2.60 Latency (us) From the above, the inherent latency of tester under different packet sizes is about 2.7us. Compared to the tens of us of SUTs latency, there are not significant impacts on the test results. In addition, the impact of inherent latency is fair to these 4 SUTs. Forwarding Performance of IPv4/IPv6 Packets on OC48 Ports Test Descriptions: To verify the performance of SUT to forward IPv4/IPv6 packets in offered packets sizes. The test requires SUT to support IPv4/IPv6 dual protocol stacks. Test Methods: The tester sends IPv4 and IPv6 traffic simultaneously in full duplex configuration, via SUT to the destination port, measure the throughput and latency with various ratio of IPv4 and IPv6 traffic. Send traffic with 50% of IPv4 and 50% of IPv6 and 100% offered load first time. If packet loss occurs, decrease the offered load in 5% resolution until the difference in offered load between successful and failed tests is less than the resolution for the test. This is the zero-loss throughput rate. At the same time, measure the latency at maximum forwarding rate. Then change the ratio of IPv4 and IPv6 traffic to test again. Increase continuously the proportion of IPv6 traffic to simulate the change of traffic characteristics in the real-world network transition. Test Descriptions: Offered load (%): initial100% with 5% increment and final 0 Offered packet types: IPv6 Percentage of IPv4 and IPv6 traffic: 50:50—10:90 (IPv4:IPv6) Offered packet size (bytes): 62 512 1518 Test duration of each packet size(s): 5 The test results are as follows: Sustainable throughput of OC-48 POS port at packet size 64 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 64 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Sustainable throughput of OC-48 POS port at packet size 512 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 512 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Sustainable throughput of OC-48 POS port at packet size 1518 bytes with different percentage of IPv4 and IPv6 traffic Sustainable Throughput of OC-48 POS Port at Packet Size 1518 bytes with different Percentage of IPv4 and IPv6 Traffic 105% 100% 95% 90% 85% Hitachi 80% NEC 75% Fujistu 70% Juniper 65% 60% 55% 50% 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Average latency (us) at test packets size 64 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 64 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/6 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper Average latency (us) at test packets size 512 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 512 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/60 30/70 20/80 10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper Average latency (us) at test packets size 1518 bytes with different percentage of IPv4 and IPv6 traffic Average Latency (us) at Test Packets Size 1518 bytes with Different Percentage of IPv4 and IPv6 Traffic 100 90 80 70 60 50 40 30 20 10 0 50/50 40/60 30/70 20/80  Ã‚  Ã‚  Ã‚   10/90 IPv4/IPv6 Test Packets Percentage (IPv4/IPv6) Hitachi NEC Fujistu Juniper IPv6 over IPv4 Configured Tunneling Performance of OC-48 POS Port Test Description: Tunneling technology is an effective means to connect separate IPv6 networks via IPv4 backbone. This item is to verify the performance of SUT when SUT encapsulates IPv6 data packets into IPv4 payload and forwards the packets. Test Method: The tester sends IPv6 data packets to SUT, and configures an IPv6 over IPv4 tunnel between SUT and the tester. Thus after SUT receives pure IPv6 packets from the tester, it will encapsulate it into IPv4 packet payload, and send IPv6 packets to destination over IPv4 network. The tester analyzes the packets forwared by the SUT at receiving end, calculates the throughput of SUT for different sizes of packets under the IPv6 over IPv4 configured tunnel. Test Results: IPv6 packet size: 512 Destination address of sending IPv6 data packets: 3FFE:0:0:4::2/64 Bandwidth range of sending IPv6 tra

Service Learning: Working at the Youth Detention Center (YDC) Essays

This semester I have been volunteering at the Youth Detention Center (YDC). YDC is a youth center for those youth ages 13-18 that have committed crimes, from running away from home to cutting the hydraulic brake lines of their parent's car. When is is concluded that the youth can no longer be active members in their communities, they are sent to YDC. There are four different units: H is for the youth that are in court right now but cannot stay at home, E is the girls unit, G unit is for the boys who committed minor crimes and felonies, and F unit is for the boys who committed major crimes and felonies such as sexual assault and dealing drugs. What first drew me to YDC was the fact that an ex-boyfriend of mine almost went there in the eighth grade, and was a troubled kid just like them. I could see a little bit of him in each of the residents and by trying to help them it felt like I was helping him in some strange way. Being a nursing major also makes me think that I can just mothe r the world, so I wanted to work at a service learning site that made me feel like I was fulfilling my mothering goals. The building itself is designed in a circular shape with an enclosed courtyard in the center for activities such as kickball, volleyball, and even skating in the winter. In each unit there are three separate living facilities. Fortunately only two of the facilities are used leaving the other free for different activities. The living quarters are made up of a living room, kitchenette, and an office area for the employees. Surrounding this area are rooms for each of the residents. In their room they have a bed, desk, and toilet; they are allowed to have two books and a Bible, a pair of sneakers, and shower shoes. All three of the li... ...s better understand how to raise their children, I can help kids get out of bad homes, and generally just be there to facilitate in any way possible. Although YDC did not change my career choice it helped me see how I can maximize the effectiveness of my profession to help others. Anytime someone asks me if YDC is a good place to volunteer at I always tell them that it is the most rewarding experience and that everyone should have the opportunity to go. One of my friends, after I told her about YDC, told me that it takes a special person to do what I do each week. I disagree though, anyone can go in for two hours and play cards each week, you get out of the experience what you put in, but I guarantee that going to YDC will affect you in some way. Works Cited Wade, C., Tavris, C., Garry, M. (2011). Psychology. Upper Saddle River, NJ: Pearson Education Inc.

Aerosol Spray Cans :: essays research papers fc

Aerosol Spray Cans   Ã‚  Ã‚  Ã‚  Ã‚  Spray cans produce an aerosol, the technical term for a very fine spray. They do this by means of a pressurized propellant, which is a liquid that boils at everyday temperatures. Inside the can, a layer of gaseous pressure increased, and eventually it becomes so high that boiling stops. when the nozzle is pressed, the gas pressure forces the product up the tube in the can and out of the nozzle in a spray or foam. The propellant may emerge as well but, now under less pressure, it immediately evaporates.   Ã‚  Ã‚  Ã‚  Ã‚  First patented in the US in 1941, aerosol spray cans have been used as convenient packages for an ever increasing range of products including paints, insecticides, and shaving cream to name a few. The can is filled with the product to be sprayed and the propellant, a compressed gas such as butane or Freon. The gas is partly liquefied by the pressure in the can, but there is a layer of free gas above the liquid. As the can empties liquefied gas vaporizes to fill the space.   Ã‚  Ã‚  Ã‚  Ã‚  The valve is normal held shut by the pressure in the can, and by the coil spring directly below the valve stem. When the push button is pressed, it forces the valve stem down in its housing, uncovering a small a small hole which leads up through the stem to the nozzle in the button. This allows the product to be forced up the dip tube by the gas pressure in the can. The nozzle is shaped to give a spray or a continuous stream.   Ã‚  Ã‚  Ã‚  Ã‚  To produce a fine mist, a propellant is used which mixes with the product. The two leave the nozzle together and the propellant evaporates a soon as it reaches the air, breaking the product in to tiny droplets. The same technique used with a more viscous liquid and a wider nozzle results in a foam. For a continuous stream of liquid or more viscous material, a nonmixing propellant is used, and the dip tube reaches into the product.   Ã‚  Ã‚  Ã‚  Ã‚  The widespread use of aerosol cans using Freon as the propellant led scientists to believe by the late 1970s that the ozone layer in the upper atmosphere, which filters out harmful Ultraviolet radiation from the sun, could be destroyed by the large quantities of fluorocarbons in the gas being release into the air. Federal controls were introduced to ban the use of Freon, and other propellants are now employed, notably butane which, however is dangerously flammable.   Ã‚  Ã‚  Ã‚  Ã‚  Among young people in United States, conventional drug or alcohol abuse has given away-for an increasing number of teen-agers-to a practice called