Assignment_

在撰写一篇关于“assignment”词根词缀的文章之前，让我们先深入了解一下这个主题。

我们需要了解“assignment”是什么意思，以及它的词根和词缀分别代表什么含义。

接下来，我们将探讨“assignment”在不同领域和语境中的应用，以及它所涉及的深层含义和广泛影响。

我们会回顾和总结所学内容，以便全面和深刻地理解“assignment”这一主题。

1. “assignment”是什么意思？“assignment”这个词源自拉丁词根“assignare”，意为“指派”或“分派”。

在英文中，这个词通常表示指定特定的任务、工作或责任给某人，也可以指分配特定的任务或活动。

“assignment”还可以指代布置的作业、任务或项目。

2. 词根词缀含义解析在“assignment”这一词中，“assign-”是词根，代表指派或分派的意思。

而后缀“-ment”则表示名词形式，将动词转化为名词，表示行为、结果或状态。

我们可以理解“assignment”为指派的行为或状态，或指派所得到的任务、职责或作业。

3. “assignment”在不同领域和语境中的应用在教育领域，“assignment”通常指代老师布置给学生的作业或任务。

而在职场中，“assignment”可能指派给员工的特定责任或工作任务。

在法律上，“assignment”也具有特定的含义，指代将权利或债务转让给他人的行为。

在项目管理、军事领域等领域中，“assignment”也有着特定的应用和含义。

4. 个人观点和理解在我看来，“assignment”不仅仅是简单的任务分配，它背后蕴含着领导能力、责任担当和团队合作的重要意义。

在现代社会中，“assignment”更多地呈现为一种团队协作和角色分工的体现，是一种高效管理和资源配置的重要手段。

5. 总结和回顾通过本文的探讨，我们对“assignment”这一主题有了全面、深刻和灵活的理解。

我们了解了它的词根词缀含义、不同领域和语境中的应用，以及个人观点和理解。

英文Assignment的写作细节（别说留学生天天就是花天酒地的玩，我们比你们要辛苦）来源：王嘉煊Sylvia的日志我们的assignment通常分为两种形式，一是essay，一是report。

二者在形式上有所差别，但大体相同。

一篇assignment上面会对写成essay还是report格式作出明确要求。

在阅读题目时，请尽量仔细相同点：1、字体：Times New Roman，字号：小四，行距：1.5倍。

请有写作之前就把这些格式调好，以避免写好后再调会出现一些意想不到的情况。

2、段与段之间隔行。

每段不要求像中文写作那样空两格，而是直接顶格写。

下面还有一些相同点，我在两种文体分开讨论时，再涉及。

区别：Essay:Essay的写作相对report要简单一些。

通常只包括三个部分，Introduction, Main Body, Conclusion. Introduction 包括topic的背景介绍和文章要解决的主要问题。

一般占总字数的10%左右。

Main Body是主体部分，占总字数80%左右。

如果题目中作了具体要求，就根据题目提到的几个方面来逐一讨论就可以了。

有的题目没有作具体要求，就根据自己的构思来写。

但要求有逻辑性。

Conclusion也是占10%，在这一段里把文章中的主要观点用一到两句话概括出来。

Essay 可以不写题目，不要把小标题加粗。

Reference的写作是两种形式都要涉及的，我放在最后来详细说。

Report:它的写法大体上和essay差不多，但要求要严格一些。

第一：标题页：包括标题和executive summary. 在Executive summary中是对文章的摘要。

这个大家都知道怎么写我就不多说了。

这两个东西一般是单独占一页第二：主体部分。

Report的主体部分，前三个和essay差不多，只是在conclusion后还有一部分就是recommendations.是对提出的问题的建议。

Assignment(essay)和presentation(report)是每个留学生必须要经历的残酷生存赛...熬不过的assignmentAssignment一般都是会换算比例记入最后module的分数的。

首先是essay，report这类学术性的。

国外的论文要求那是相当严格，特别是引用的规则。

论文中提到的每一个观点都需要各种理论学说来支持。

而这些theory的来源要求也很高，如果你想要得高分，不能是随便一篇文章里的某一个所谓的expert说的，必须是相关领域相关专家发表在相关学术期刊上的，经过了Peer Review同行审查的最佳。

除了theory，必要的时候各种data以及report结果也需要引用，用于支撑你文章的观点。

所以，我们在写essay的时候，需要大量引用evidence来支撑文章，而每一个evidence都必须被标明作者以及年份，在文章中为citation，在文末为reference。

如果没有标明，则将被视为plagiarism抄袭，后果很严重，甚至导致直接挂科。

而即使你做了citation，也不能直接一字不动地照搬原文语句，需要通过quotation，paraphrase 或者summary来改写文章。

目前英国高校普遍要求通过数据库系统提交作业，自动在超过80亿的文献和网页中搜索和你的作业相似度高的文字，稍不注意就可能被电脑判断为相似度高的”伪剽窃“。

所以，想要写好一篇report和essay：1. 你要认真读懂并且理解老师给的题目2. 你要清楚这题目跟学过的那些知识点哪些理论可以联系得上3. 你要学会怎么规划整篇文章的结构以及每部分大致的字数，最后按顺序一部分一部分的去完成4. 你要学会规避“伪剽窃”这类系统性的写作风险这就是大部分中国留学生不能毕业的原因经常被坑/坑人的presentationpresentation分为个人和小组的，需要根据老师布置的主题来准备ppt和稿子。

DIRECTORATE OF LEARNING SYSTEMSDISTANCE EDUCATION COURSESStudent Number: ________________________________Name: _________________________________________Address: ______________________________________________________________________________________INTEGRATED HIV/AIDSTutor Marked AssignmentUnit 4: HIV Associated Conditions in Adults & Adolescents Instructions: Answer all the questions in this assignment.1. List the common neurological diseases seen in HIV positive patients_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________2. Kasuku, who is known to be HIV positive, presents to hospital with a two week historyof weakness on one side of the body and difficulty with speech. The following are possible causes of his condition (indicate true or false).A. Candia albicansB. Cryptococcal meningitisC. MeningiomaD. LymphomaE. Toxoplasmosis3. Fatuma is a 38 year old woman who is HIV positive. She comes to the hospitalcomplaining of difficulty walking and leg weakness of sudden onset. What othersymptoms might she experience that are related to neuropathy?A. HeadacheB. IncontinenceC. SeizuresD. FeverE. Difficulty in breathing4. List the possible complications of peripheral neuropathy and outline how you willmanage them._____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________5. Juma, who is 27 years old, complains of hearing voices and seeing people with swordschasing him. He tested HIV positive 3 years ago. The following statements are true of Juma’s condi tion.A. It is unrelated to his HIV statusB. HIV does not affect the brain directlyC. He should be given high doses of antipsychotic medicationD. The absence of fever makes infection unlikely6. a) What is delirium?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________b) List the possible causes of delirium in HIV positive patients_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________7. List the common respiratory conditions seen in HIV/AIDS__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________8. Which of the following drugs are used in the prevention of Tuberculosis?A. ClarithromycinB. CotrimoxazoleC. PyrazinamideD. IsoniazidE. Ketocnazole9. Which of the following statements are true regarding TB in HIV infection?A. HIV positive people with a negative Mantoux test should be offered prophylaxisagainst TB infectionB. Tuberculosis treatment is given for a longer timeC. It only occurs on those who are severely immunosuppressedD. It is difficulty to cure10. Outline the steps that should be taken to prevent tuberculosis in healthcare facilities.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________11. The following are useful in the management of pneumocystis carinii pneumoniaA. Penicillin VB. CotrimoxazoleC. ErythromycinD. DapsoneE. Prednisolone12. List the common causes of diarrhoea in HIV positive patients.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________13. Jama, who is HIV positive, is 22 years of age and works as a herds-boy. He spendsmost of the day in the fields and the only water available to him is from streams. He complains that he gets dizzy during the middle of the day. He has been having episodes of diarrhoea on and off for the last 4 weeks. What advise would you give Jama?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________14. Amina is a 37 year old housewife. She was found to be HIV positive during her lastpregnancy 2 years ago. She has noticed that she has been loosing weight over the last 3 months. She has mouth sores that are painful and occasionally has central chest pain when she swallows food.a. List the common causes of oral sores in HIV infection.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________b. On looking inside Amina’s mouth, you notice tha t she has white plaques (patches) atthe back of the mouth. What is the most likely cause of these patches?______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________c. What are some of the effects of oral disease in HIV/AIDS?______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________e. What treatment would you give Amina?_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________15. List the possible causes of weight loss in HIV/AIDS:_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________16. How do you assess a patient with weight loss in the HIV Clinic?_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________17. List the common causes of skin disease in HIV/AIDS______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________b. W hat are the common sites for Kaposi’s sarcoma lesions? How can these lesions bedescribed?________________________________________________________________________ ________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________c. Why is it important to differentiate between lesions due to seborrheic dermatitis, andthose due to fungal infection? Mention some of the differences between these conditions. How would you treat them?________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ _______________________________________________________________________Congratulations! You have now come to the end of this unit. Remember to indicate your Student Number, names and address before sending this assignment. Once you complete this assignment, post or bring it in person to AMREF Training Centre.。

英文Assignment和Dissertation的写作细节（珍藏版）Dissertation一、Dissertation大体结构1.首先是Cover Page，即封面，包括论文的题目，作者姓名，所在学院，学校和上交时间等信息。

2.Declaration，也就是声明，“我声明，所有成果除了我已经注释的，其他均为我自己的研究成果，没有剽窃他人的”，之后是上交时间，指导导师，签名，学院等。

3.Acknowledgment，写要感谢的人，导师是必须要感谢的，当然还可以感谢其他人，这个随意。

4.Content，目录，这个要两端对其，整体格式一致，用Word中的目录索引功能自动生成。

一般三级目录就可以了。

比如3，3.1，3.1.2。

5.List of Figures，也就是所有图片的一个目录，包括所有在论文中出现的图片标题，不要把图片也贴上，只要标题。

比如：1.1 XXXX标题名称2.1 XXXX标题名称6.List of T ables，和上面类似，就是表格的目录。

(注：以上内容的页码为罗马数字，从下面的Abstract开始，为阿拉伯数字并从1重新开始，这个在word中可以设置。

目录第一条从Introduction开始，而不是Abstract，切记。

）7.Abstract，也就是摘要。

一般50-60页的论文摘要1页以内即可，最好控制在半页到3/4页，不要多。

8.Introduction，介绍部分。

9.Background 或者Literature Review，题目只要涉及这些方面即可，一般是这两个。

内容也是。

(具体写作我后面会具体说)。

10.Proposed Method也就是主体部分，题目自定或者问问导师，但是内容是你的研究成果的描述。

11.Analytical and T est Results，分析和测试结果，题目自定，内容主要就是测试结果。

12.Discussion,对结果产生的分析和解释，也有并入上面的一说。

第一讲练习试将下列句子译成汉语：1．The many colors of a rainbow range from red on the outside to violet on the inside.彩虹有多种颜色，外圈红，内圈紫。

2. He had a disconcerting habit of expressing contradictory ideas in rapid succession.他有一种令人难堪的习惯：一会儿一个看法，自相矛盾，变化无常。

3.This was an intelligently organized and fervent meeting in a packed Town Hall, with Mr. Strong in the chair.这是一次精心组织起来的会议。

市政厅里济济一堂，热情洋溢，主持会议的是斯特朗先生。

4.Power can be transmitted over a great distance withpractically negligible loss if it is carried by an electric current.电流可以把动力传送到很远的地方，其消耗几乎可以忽略不计。

5.The present onslaught of vehicles poses a serious threat to urban life and pedestrian peace of mind.当前，车辆横冲直闯，严重地威胁着城市生活，路上行人无不提心吊胆。

6.Change of information, if any, concerning the contents of this section will be found in the appendix at the end of this book.本节内容如有更改，均见本书末附录。

7.She said, with perfect truth, that “it must be delightful to have a brother,”and easily got the pity of tender-hearted Amelia, for being alone in the world, an orphan without friends or kindred.她说道，“有个哥哥该多好啊，”这话说得入情入理。

Chapter 1321.The document becomes a negotiable instrument wherein the title to themerchandise goes with possession of the bill of lading.此提单成为流通票据，其货物的所有权随着提单的持有者而转移。

2.We surrendered a clean on board bill of lading for the negotiation ofpayment.议付时，我们提交了清洁已装船提单。

3.You may draw a clean draft on us for the value of this sample shipment.你方可向我方开出光票索取这批货的价款。

4.The balance of USD 10,000 has been drawn at sight on you.我方已向你方开出USD10,000的即期汇票。

5.You can draw on us against this credit.你方可以凭此信用证向我方开立汇票。

6.Bill of lading should be made out to order and endorsed in blank.提单应当要有指示并且要有空白背书。

7.The customary letter of credit calls for “a full set on board ocean bills oflading to order of shipper, blank endorsed”.习惯上的信用证要求全套的已装船提单要有承运人指示，及空白背书。

8.If blank endorsement is made, the holder of the B/L has the right to takedelivery of the goods.如果已经空白背书，提单的所有者就有权提取货物。

Assignment/p/2474897921翻译/cn/help/simulink/slref/assignment.html赋值到指定元素的信号库Math OperationsAssignment块分配指定元素的值的信号。

您可以指定元素的索引被分配的值块的对话框中输入索引，或块通过连接一个外部索引的来源或来源。

块的数据端口处的信号，标记为U，指定值被分配到Y。

该块从数据信号中的元素替换指定Y的元素基于该值，您输入的Number of output dimensions参数，显示一个表的索引选项。

表中的每一行对应输出维度的一个在Number of output dimensions中.对于每个维度，可以定义的元素的信号来工作。

指定为一个1-D的信号和一个2-D信号的矩阵信号作为一个矢量信号。

当您设定的分配块的块图标变化，操作多维信号。

例如，假设一个5-D信号基于索引模式。

该表在分配块对话框中切换到包括一个行的每个维度。

如果你定义了每个维度的以下项：∙1Index Option, 选择Assign all∙2Index Option, 选择Index vector (dialog)Index, 输入[1 3 5]∙3Index Option, 选择Starting index (dialog)Index, 输入4∙4Index Option, 选择Starting index (port)∙5Index Option, 选择Index vector (port)分配的值将是Y(1:end,[1 3 5],4:3+size(U,3),Idx4:Idx4+size(U,4)-1,Idx5)=U, where Idx4和Idx5是输入端口4和5的维度.分配块的数据端口标记为U.本节的其余部分是指为了简化解释块的使用为数据端口U。

您可以使用块将值指派给向量，矩阵或多维信号。

您可以使用一个数组作为分配块的输入信号的总线。

1.Present the OSI layered model. (Outcome 4.1)(1)Present the seven layers of the OSI model.Following is a figure for the seven layers.Figure 1-1 The seven layers(2)The function of each layer.Table 1-1 The function of seven layers(3)The relationship of layers.Moving from the top, down - messages get larger and larger. A message is passed down, and the lower layer adds a header to it. This is called encapsulation, because it is like placing an object into a capsule. The header is sometimes called a wrapper. Each successive lower layer encapsulates what it receives from the layer above it. Moving from the bottom, up - messages get smaller and smaller. A message is first stripped of it's header, and then the inner contents (the "data" portion) is passed up. This is "decapsulation" but no one uses that term. Each successive upper layer receives the data message from the layer below, and then strips off it's own header and passes the data up.2.Explain the role of drivers in a network, discussing their relationship to the NOS and OSI model. (Outcome 4.2)(1)The function of drivers in a network.LAN drivers direct the function of the hardware used to transfer data to and from computers in the LAN. These drivers come in many types, and they can be installed on a user's computer or on a shared server. Network hardware devices, which might need LAN drivers to function, include network routers, modems, network cards, or network card adapters.(2)Drivers’ relationship to the Windows server 2003.Drivers are one kinds of software help communication between Win 2003 and hardware. The connecting hardware can never work without the matching driver. In usually, Win 2003 owns the driver. It can update the driver by the “Windows Update”from the control platform. If it didn’t owns the driver, then it need the CD which as the additional with the hardware, or search and download from the internet.(3)Drivers’ relationship to the OSI model.Different driver works on different layer. The File system driver works on application layer, session and presentation layers. The gate way works on the Transport layer. The router works on the Network layer. The switch works on the Data link layer. The repeater works on Physical layer.3.Discuss how drivers are selected and implemented for various network components; install NIC driver and demonstrate how to remove and update. (Outcome4.3)(1)Discuss how drivers are selected and implemented for sound card, network interface card and video card.Every computer has its own drivers includes sound card, network interface card and video card and so on. When we buy the computer, a CD/DVD contain drivers will be give us. We can use the CD/DVDs to select and implement the drivers. And we can download some driver software to check out whether our computer lack of drivers, then select the driver and implement it.(2)Install Microsoft Loopback Adapter driver.Following are the figures for install steps:Figure 3-1 Installation1Figure 3-2 Installation2Figure 3-3 Installation3Figure 3-4 Installation4Figure 3-5 Installation5Figure 3-6 Installation6Figure 3-7 Installation7Figure 3-8 Installation8(3)Remove and update the Microsoft Loopback Adapter driver. Following are figures show the steps for remove and update:Figure 3-9 Step1Figure 3-10 Step2Figure 3-11 Remove and update4.Explain the detailed operation of different IEEE 802.N network configurations. (Outcome 4.4)Table 4-1 The detailed operation of different IEEE 802.N5.Refer the 802 protocols to the existing OSI layers. (Outcome 4.5)(1)The IEEE 802 model.IEEE 802 refers to a family of IEEE standards dealing with local area networks and metropolitan area networks.More specifically, the IEEE 802 standards are restricted to networks carrying variable-size packets. (By contrast, in cell relay networks data is transmitted in short, uniformly sized units called cells. Isochronous networks, where data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also out of the scope of this standard.) The number 802 was simply the next free number IEEE could assign,[1] though “802” is sometimes associated with the date the first me eting was held — February 1980.The services and protocols specified in IEEE 802 map to the lower two layers (Data Link and Physical) of the seven-layer OSI networking reference model. In fact, IEEE 802 splits the OSI Data Link Layer into two sub-layers named Logical Link Control (LLC) and Media Access Control (MAC), so that the layers can be listed like this:Data link layer⏹LLC Sublayer⏹MAC SublayerPhysical layerThe IEEE 802 family of standards is maintained by the IEEE 802 LAN/MAN Standards Committee (LMSC). The most widely used standards are for the Ethernet family, Token Ring, Wireless LAN, Bridging and Virtual Bridged LANs. An individual Working Group provides the focus for each area.(2)Compare the 802 protocols with the OSI layers.Figure 5-1 ComparisonThe main thing to note is that the original OSI model didn't include a "medium access" layer because the assumption was made that all networks would be made of point-to-point lines. Boy, were they wrong. They later hacked a medium access control sublayer into the data link layer.Basically, the OSI physical layer corresponds to the IEEE 802 physical layer. Then, the OSI data link layer corresponds to the 802 LLC and MAC layers.(3)Define and explain the data link layer in IEEE Project 802.The bottom two OSI layers, the physical layer and the data-link layer, define how multiple computers can use the network simultaneously without interfering with each other.The IEEE 802 project incorporated the specifications in those two layers to create standards that have defined the dominant LAN environments. Figure 5.8 shows the data-link layer and its two sublayers.After deciding that more detail was needed at the data-link layer, the 802 standards committee divided the data-link layer into two sublayers:Logical Link Control (LLC) Establishing and terminating links, controlling frametraffic, sequencing frames, and acknowledging frames●Media Access Control (MAC) Managing media access, delimiting frames,checking frame errors, and recognizing frame addressesLogical Link Control (LLC) SublayerThe LLC sublayer manages data-link communication and defines the use of logical interface points called service access points (SAP). Other computers can refer to and use SAPs to transfer information from the LLC sublayer to the upper OSI layers. Category 802.2 defines these standards.Media Access Control (MAC) SublayerAs Figure 5.9 indicates, the MAC sublayer is the lower of the two sublayers, providing shared access to the physical layer for the computers' NICs. The MAC layer communicates directly with the NIC and is responsible for delivering error-free data between two computers on the network.6.Relate how architecture influences access and control of the network and draw out merits of different architectures. (Outcome 4.6)(1)Explain CSMA/CD and Token Passing access and control method.a)CSMA/CDCarrier sense multiple access with collision detection (CSMA/CD) is a Media Access Control method in which:● A carrier sensing scheme is used.● A transmitting data station that detects another signal while transmitting a frame,stops transmitting that frame, transmits a jam signal, and then waits for a random time interval before trying to resend the frame.CSMA/CD is a modification of pure carrier senses multiple accesses (CSMA). CSMA/CD is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus shortening the time required before a retry can be attempted.b)Token PassingIn telecommunication, token passing is a channel access method where a signal called a token is passed between nodes that authorizes the node to communicate. The mostwell-known examples are token ring and ARCNET.Token passing schemes provide round-robin scheduling, and if the packets are equally sized, the scheduling is max-min fair. The advantage over contention based channel access is that collisions are eliminated, and that the channel bandwidth can be fully utilized without idle time when demand is heavy. The disadvantage is that even when demand is light, a station wishing to transmit must wait for the token, increasing latency.(2)Relate how architecture influences CSMA/CD and Token Passing.In the CSMA/CD media-access scheme, network devices contend for use of the physical network medium. CSMA/CD is therefore sometimes called contention access. Examples of LANs that use the CSMA/CD media-access scheme are Ethernet/IEEE 802.3 networks, including 100BaseT.In the token-passing media-access scheme, network devices access the physical medium based on possession of a token. Examples of LANs that use the token-passing media-access scheme are Token Ring/IEEE 802.5 and FDDI.(3)Draw out merits of Ethernet, Token Ring and ArcNet.a)Merits of EthernetConceptually Simple:Ethernet is simply daisy-chained together with coax cable and "T" adapters. There are usually no hubs, transceivers, or other devices used.Relatively Inexpensive:Due to the simplicity inherent in the design of Ethernet, it can be an inexpensive technology to implement.Noise Immunity:The coaxial cable used in a Ethernet network is very well shielded, and has a very high immunity from electrical noise caused by outside sources.b)Merits of Token RingToken Ring networks are deterministic in nature. In English, this means that the nodes may only transmit at certain, well defined times. This eliminates incidents of two or more nodes transmitting at the same time and corrupting each other's transmission(collisions). The elimination of collisions results in a network where data almost always gets to its destination on the first attempt, greatly reducing retransmissions which waste bandwidth. The end result is a higher effective bandwidth at the same wire speed.c)Merits of ArcNetARCNET added a small delay on an inactive network as a sending station waited to receive the token, but Ethernet's performance degraded drastically if too many peers attempted to broadcast at the same time, due to the time required for the slower processors of the day to process and recover from collisions.[citation needed] ARCNET had slightly lower best-case performance (viewed by a single stream), but was much more predictable. ARCNET also has the advantage that it achieved its best aggregate performance under the highest loading, approaching asymptotically its maximum throughput.7.Describe scenarios where one architecture might be favored over another. (Outcome 4.7)(1)Describe the features, cabling and components of Ethernet, Token Ring, Apple Talk and ArcNet.a)EthernetTable 7-1 The features of EthernetTable 7-2 The cablingComponentsIn an Ethernet LAN, the components include NIC, switch, hubs, router, and the cables.b)Token RingA Token Ring network includes the following features:•Star-wired ring topology•Token-passing access method•Shielded and unshielded twisted-pair (IBM Types 1, 2, and 3) cabling •Transfer rates of 4 and 16 Mbps•Baseband transmission•802.5 specificationsCablingThe STP or UTP cable to a hub connects computers on a Token Ring network. Figure 3.28 shows cable length limits for three types of cabling. Token Rings use IBM Type 1, 2, and 3 cabling. Most networks use IBM Cabling System Type 3 UTP cabling. ComponentsIn a Token Ring network, the components include Hub, Cabling, Connectors, Patch Cables, Media Filters, Patch Panels, Repeaters, Fiber-Optic Cable.c)Apple TalkFeatures•LocalTalk networks, which have a single network number and can have as many as 254 nodes. (They are actually limited to 32 or fewer nodes because of media capacity.)•EtherTalk and TokenTalk networks, which can be assigned a network range sothat the network can have more nodes. EtherTalk and TokenTalk networks can have as many as 253 nodes for every number in the network range, for a maximum of 16.5 million nodes.LocalTalk networks, which each must be in a single zone. Each EtherTalk and TokenTalk network can have multiple zones, and individual nodes on a network can be configured to be in any one of the network's associated zones.CablingSTP cabling is most often used in a bus or tree topology. A LocalTalk network supports a maximum of 32 devices.Because of LocalTalk's limitations, manufacturers other than Apple are often preferred for cabling. Farallon PhoneNet, for example, can handle 254 devices. PhoneNet uses telephone cable and connectors and can be implemented as a bus network or plugged into a central wiring hub to form a star topology.ComponentAppleTalk networks are arranged hierarchically. Four basic components form the basis of an AppleTalk network: sockets, nodes, networks, and zones.d)ArcNetFeaturesDeterministic Performance - Users Can Calculate the Worst Case Node to Node Message TimeLogical Ring - Nodes Automatically Find Their Neighbor to Create A Ring Automatic Reconfiguration - A New Node Joins the Ring Automatically Without Software InterventionBroadcast and Directed MessagesMulti-Master with Automatic Token GenerationCabling Options - Coaxial, Fiber, EIA-485 Twisted PairHigh Speed - Standard 2.5 Mbps, Optionally 19 kbps to 10 MbpsLow Cost ChipsLow Protocol Overhead - 3 or 4 Bytes—Good Usage of Available Bandwidth Variable Packet Size - 0 to 507 BytesBit Rate Scalable up to 10 Mbps—Grows with Your ApplicationHigh Noise ImmunityEasy/Simple Manageable Technology—No Special Development Tools Required CablingThe standard cabling used for ArcNet is 93-ohm RG-62 A/U, coaxial cable. ArcNet also supports twisted-pair and fiber-optic media. The distances between computers vary, depending on the cabling and the topology.(2)Describe appropriate application scenarios of Ethernet, Token Ring, Apple Talk and ArcNet.a)EthernetNearly all scenarios can use the Ethernet, it is so popular in the world, but its limitation is that if many people want to connect the Ethernet in a area, the speed will be slow down.b)Token RingToken Ring networks give the benefit of a very fast. deterministic network, but require a major commitment to properly plan and maintain. Before choosing Token Ring as the technology for a particular project, it is very important to ensure that the organization has the ability to commit the time and resources necessary. Not doing so is basically a recipe for disaster.c)Apple talkAppleTalk is the Apple network architecture and is included in the Macintosh operating system software. Figure 7-1 shows a typical AppleTalk network configuration. This means that network capabilities are built into every Macintosh. It is used for sharing information and print etc.Figure 7-1 Apple talk networkd)ArcNetDatapoint Corporation developed the Attached Resource Computer Network (ArcNet) in 1977. Figure 7-2 shows a star-wired ArcNet. It is a simple, inexpensive, flexible network architecture designed for workgroup-size networks. The first ArcNet cards were shipped in 1983.Figure 7-2 Simple star-wired ArcNet8.Discuss the role of packets and how they are built up from their various components, giving an example where data packets are transmitted through different layers of the OSI model. (Outcome 5.1)(1)Discuss the role of the frame and how it is built up from its components.In computer networking, a frame is a data packet on the Layer 2 of the OSI model. A frame is "the unit of transmission in a link layer protocol, and consists of a link-layer header followed by a packet." Examples are Ethernet frames (maximum 1500 byte plus overhead), PPP frames and V.42 modem frames.The Ethernet II frame is a standard format for data transmitted via an Ethernet network. The frame refers to a collection of byte values in specified locations that identify the frame sender, the intended receiver, the data payload and an error-check value. Packaging data into frames such as this enables data to be sent via a packet-switching network rather than requiring a constant end-to-end connection. (2)Discuss the role of the packet and how it is built up from its components. Packets are constructed in such a way that layers for each protocol used for a particular connection are wrapped around the packets, like the layers of skin on an onion.At each layer (except perhaps at the application layer), a packet has two parts: theheader and the body. The header contains protocol information relevant to that layer, while the body contains the data for that layer, which often consists of a whole packet from the next layer in the stack. Each layer treats the information it gets from the layer above it as data, and applies its own header to this data. At each layer, the packet contains all of the information passed from the higher layer; nothing is lost. This process of preserving the data while attaching a new header is known as encapsulation.(3)Discuss the role of the segment and how it is built up from its components. Transmission Control Protocol accepts data from a data stream, segments it into chunks, and adds a TCP header creating a TCP segment. The TCP segment is then encapsulated into an Internet Protocol (IP) datagram. A TCP segment is "the packet of information that TCP uses to exchange data with its peers."A TCP segment consists of a segment header and a data section. The TCP header contains 10 mandatory fields, and an optional extension field (Options, pink background in table).The data section follows the header. Its contents are the payload data carried for the application. The length of the data section is not specified in the TCP segment header. It can be calculated by subtracting the combined length of the TCP header and the encapsulating IP header from the total IP datagram length (specified in the IP header).(4)Taking network layer for example, describe how data packets are transmitted through Transmission layer, Network layer and Data Link layer.a)Layer 4: Transport Layer•Manages end-to-end message delivery in network•Provides reliable and sequential packet delivery through error recovery and flow control mechanisms•Provides connectionless oriented packet deliveryb)Layer 3: Network Layer•Determines how data are transferred between network devices•Routes packets according to unique network device addresses•Provides flow and congestion control to prevent network resource depletionc)Layer 2: Data Link Layer•Defines procedures for operating the communication links•Frames packets•Detects and corrects packets transmit errors9.Discuss the role of protocols at different layers of the OSI model, describing the function of specific protocols. (Outcome 5.2)(1)Discuss the role of protocols at physical layer, data link layer, network layer, transport layer, session layer, presentation layer and application layer of the OSI model.Figure 9-1 The protocols at physical layera)Medium-access protocolsDefines the addressing that distinguishes each node an a NetWare network.b)Internetwork Packet Exchange (IPX)Defines the addressing schemes used on a NetWare network.c)Sequenced Packet Exchange (SPX)Provides security and reliability to the IPX protocol.d)Routing Information Protocol (RIP)Facilitates the exchange of routing information on a NetWare network.e)Service Advertising Protocol (SAP)Allows service-providing nodes to advertise their services and addresses.f)NetWare Core Protocol (NCP)Defines the connection control and service request encoding that make possible the interaction between clients and servers(2)Describe the function of FTP, HTTP, TELNET, SMPT, TCP, UDP, IP, ARP and ICMP.a)FTPFile Transfer Protocol (FTP) is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on client-server architecture and uses separate control and data connections between the client and server. FTP users may authenticate themselves using a clear-text sign-in protocol but can connect anonymously if the server is configured to allow it.b)HTTPThe Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.c)TELNETTelnet is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communications facility using a virtual terminal connection. User data is interspersed in-band with Telnet control information in an 8-bit byte oriented data connection over the Transmission Control Protocol (TCP). d)SMTPSMTP is a standard electronic-mail protocol that handles the sending of mail from one SMTP to another SMTP server. To accomplish the transport, the SMTP server has its own MX (mail exchanger) record in the DNS database that corresponds to the domain for which it is configured to receive mail.e)TCPThe Transmission Control Protocol (TCP) is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered delivery of a stream of bytes from a program on one computer to another program on another computer. TCP is the protocol that major Internet applications such as the World Wide Web, email, remote administration and file transfer rely on. Other applications, which do not requirereliable data stream service, may use the User Datagram Protocol (UDP), which provides a datagram service that emphasizes reduced latency over reliability.f)UDPUDP uses a best-effort delivery system, similar to how first class and lower postal services of the Indian Postal Service work. With a first class letter (post card), you place the destination address and put it in your mailbox, and hope that it arrives at the destination.g)IPThe Internet Protocol (IP) is the principal communications protocol used for relaying datagrams (packets) across an internetwork using the Internet Protocol Suite. Responsible for routing packets across network boundaries, it is the primary protocol that establishes the Internet.IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering datagrams from the source host to the destination host solely based on their addresses. For this purpose, IP defines addressing methods and structures for datagram encapsulation.h)ARPThe Address Resolution Protocol (ARP) is an Internet layer protocol that helps TCP/IP network components find other devices in the same broadcast domain.ARP resolves an IP address of a destination to the MAC address of the destination on the same data link layer medium, such as Ethernet. Remember that for two devices to talk to each other in Ethernet (as with most layer 2 technologies), the data link layer uses a physical address (MAC) to differentiate the machines on the segment. When Ethernet devices talk to each other at the data link layer, they need to know each other MAC addressesi)ICMPICMP provides network diagnostic functions and error reporting. One of the most used IP commands is the Packet Internet Grouper (PING) command. When a host PINGS another client, it sends an ICMP ECHO request, and the receiving host responds with an ICMP ECHO REPLY. PING checks network connectivity on clientsand routers. ICMP also provides a little network help for routers. When a router is being overloaded with route requests, the router sends a source quench message to all clients on the network, instructing them to slow their data requests to the router.10.Explain examples of transmission between different network layers. (Outcome 5.3)(1)Explain the process of data transmission how host A sends the data via different layers.Figure 10-1 The process of data transmission1When host A sends a message to host B, the message moves down the successive layers of host A, from the application layer to the presentation layer, to the session layer, etc., until it reaches the physical layer. It is then transmitted across the communication line between host A and node X, and moves up the three layers of node X and down again. Then it is transmitted to node Y where it goes through the same procedure, and finally is transmitted to host B, where it moves up its seven layers, until it arrives at the application layer of host B.(2)Explain the process of data transmission how host B receives the data via different layers.Figure 10-2 The process of data transmission2System B receives the request on Layer 1, and begins the decapsulation process, stripping the Layer 1 headers and footers off to reveal the Layer 2 information, and so forth, all the way up to the 7th layer.ConclusionAfter finished this assignment, I know the OSI layered model, the role of drivers in a network, and their relationship to the NOS and OSI model function of drivers in a network. I know how drivers are selected and implemented for various network components. I learn how to install, remove and update NIC driver. I know the detailed operation of different IEEE 802.N network configurations, the 802 protocols to the existing OSI layers, how architecture influences access and control of the network and merits of different architectures. I understand some scenarios where architecture might be favored over another, the role of packets and how they are built up from their various components. I also know the example where data packets are transmitted through different layers of the OSI model, the role of protocols at different layers of the OSI model, the function of specific protocols examples of transmission between different network layers.Through this assignment, I learn a lot.Reference/wiki/OSI_model#Cross-layer_functions [Accessed on June 25, 2011]/wiki/IEEE_802 [Accessed on June 25, 2011]/ccna/internetworking/lanprotocols.html [Accessed on June 25, 2011]/wiki/Token_passing [Accessed on June 25, 2011]/wiki/Carrier_sense_multiple_access_with_collision_detection /wiki/ARCnet [Accessed on June 25, 2011]/~cyh/cis370/ebook/ch03f.htm [Accessed on June 25, 2011] http://docstore.mik.ua/orelly/networking_2ndEd/fire/ch04_01.htm [Accessed on June 25, 2011]/wiki/Transmission_Control_Protocol#TCP_segment_structure [Accessed on June 25, 2011]/n_plus_certifications/protocol_tcp_ip_udp_ftp_t ftp_smtp.htm [Accessed on June 25, 2011]。