計(jì)算機(jī)網(wǎng)絡(luò)體系結(jié)構(gòu)畢業(yè)論文外文翻譯.doc

1、.附錄AWith the new network technology and application of the continuous rapid development of the computer network should. Use of becoming increasingly widespread, the role played by the increasingly important computer networks and human. More inseparable from the lives of the community's reliance

2、on them will keep growing. In order for computers to communicate, they must speak the same language or protocol. In the early days of networking, networks were disorganized in many ways. Companies developed proprietary network technologies that had great difficulties in exchanging information with o

3、ther or existing technologies; so network interconnections were very hard to build. To solve this problem, the International Organization for Standardization（ISO）created a network model that helps vendors to create networks compatible with each other. Finding the best software is not easy. A better

4、understanding of what you need and asking the right questions makes it easier. The software should be capable of handling challenges specific to your company. If you operate multiple distribution centers, it may be beneficial to create routes with product originating from more than one depot. Few so

5、ftware providers though, are capable of optimizing routes using multiple depots. The provider should be able to support installation of its product. Make sure to clearly understand what training and software maintenance is offered. Obviously, selecting the right routing/scheduling software is critic

6、ally important. Unfortunately, some companies are using software that may not be best suited to their operation. Logistics actives with responsibility for approving the software ought to be comfortable they've made the right decision. It is important to realize that not all routing/scheduling so

7、ftware is alike！There questions to ask are： Which operating system is used？ How easy is the software to use？ Here is a good way to tell. Ask if its graphical user interface（GUI）is flexible. Find out about installation speed - how long does it take？ Is the software able to route third party customers

8、 with your core business？ When was the software originally released and when was it last upgraded？In 1984, ISO released the Open Systems Interconnection（OSI）reference model, which is a well-defined set of specifications that ensures greater compatibility among various technologies. In fact, OSI is a

9、 description of network communication that everyone refers to. It is not the only network model, but it has become the primary model for network communication. You will see further in this chapter, that the TCP/IP model is only a reduced version of the OSI model. The OSI model consists of seven laye

10、rs, each illustrating a particular network function. meanwhile, ASP continues to evolve. With the arrival of the millennium came the arrival of ASP version 3. 0. Version 3. 0 was released along with Internet Information Server（IIS）version 5. 0 as part of the highly anticipated Microsoft Windows 2000

11、. By far, the most important new feature of version 3. 0 is the addition of a seventh, intrinsic object called ASP Error which should greatly simplify error handling. Other new features include the addition of three new methods to the Server object, and two new methods to both the Application object

12、 and the Session object. When programmers design an image editor for example, they don't have to think about adding OSI Layer 7 capabilities to that software, because it has no need for communication with other computers. On the other hand, when creating an FTP client, they must add communicatio

13、n capabilities to that software. At Layer 7 we usually find Telnet, FTP, HTTP, SMTP, SNMP, or SSH. When we say, For Example, Layer 7 filtering, we refer to filtering application data, regardless of what port or computer it may come from. OSI will be a computer network architecture（architecture）is di

14、vided into the following seven：The first layer：physical layer（Physical Layer）, provides communications equipment for the mechanical, electrical and functional characteristics and process for the establishment, maintenance and removal of the physical link connection. Specifically, the provisions of t

15、he mechanical properties required for network connectivity connector dimensions, pin number and order situation, etc. ;the provisions of the electrical characteristics of the physical connection in the bit stream transmission line signal level of the size, impedance matching , transfer rate from the

16、 constraints; features refers to the distribution of the various signals to the exact meaning of the signal, that is the definition of the DTE and DCE function between the various lines; order characteristics of the definition of the use of bit stream signal transmission lines for a group of rules r

17、efers to the physical connection of the establishment, maintenance, exchange of information, DTE and DCE on the circuit on double-action series. In this layer, data units known as bits（bit）. Belong to the typical definition of the physical layer specification included： EIA / TIA RS-232, EIA / TIA RS

18、-449, V. 35, RJ-45 and so on. The second layer： data link layer（Data Link Layer）： in the physical layer bit stream to provide services based on adjacent node between the data link, through the provision of error control data frame（Frame）in the channel error-free transmission, and the action of the s

19、eries circuit. Data link layer in the physical media is not reliable to provide reliable transmission. The role of this layer include： addressing the physical address, data framing, flow control, data error, such as re-issued. In this layer, data units known as the frame（frame）. Data link layer prot

20、ocol, including representatives of： SDLC, HDLC, PPP, STP, such as frame relay. The third layer is the network layerIn the computer network to communicate between two computers may be a lot of data link may also go through a lot of communication subnet. Network layer of the task is to choose a suitab

21、le inter-network routing and switching nodes, to ensure timely delivery of data. Network layer will provide the data link layer packet frame components, including network layer in the package header, which contains the logical address information - - the source site and destination site address of t

22、he network address. If you're talking about an IP address, then you are in dealing with the problem of Layer 3, which is “data packets”, rather than layer 2 of the “frame. ” IP is layer 3 part of the problem, in addition to a number of routing protocols and ARP（ARP）. All things related to routin

23、g in Layer 3 processing. Address resolution and routing is an important objective of Level 3. Network layer can also achieve congestion control features such as Internet interconnection. In this layer, data packets as the unit（packet）. Representatives of the network layer protocol, including: IP, IP

24、X, RIP, OSPF, etcThe fourth tier is the transport layer process information. At fourth floor unit, also known as data packets（packets）. However, when you talk about TCP protocol, such as concrete and specific when the name, TCP data unit known as paragraph（segments）and the UDP protocol data unit ref

25、erred to as “datagram（data grams）”. This layer is responsible for obtaining all the information, therefore, it must be tracking data cell debris, out-of-order packets arrive in the transfer process and other possible risk. No. 4 for the upper layer to provide end-to-end（the end-user to end-users）of

26、a transparent and reliable data transmission services. Transparent by means of transmission is transmitted in the communication process of the upper layer shielding the communication transmission system details. Representatives of the Transport Protocol： TCP, UDP, SPX, etcThe fifth layer is the sess

27、ion layerThis layer can also be known as the dialogue meeting between layers or layer, in the session layer and above the high-level, the data transmission is no longer the other named units, known collectively as the message. Session layer does not participate in specific transmission, It provides,

28、 including access to authentication and session management, including the establishment and maintenance of mechanisms for communication between applications. If the server to verify user login is completed by the session layer. The sixth layer is Presentation LayerThe main solution to support this l

29、evel of information that the problem of syntax. For the exchange of data will be suitable for a user from the abstract syntax, into a system suitable for the use of OSI transfer syntax. To provide formatting and conversion of that data services. Data compression and decompression, encryption and dec

30、ryption so that the layers are responsible for. The seventh layer application layer, application layer for the operating system, applications or network services access the network interface. Agreement on behalf of the application layer, including: Telnet, FTP, HTTP, SNMP, etc. . Through the OSI lay

31、ers, information from a computer software application for transfer to another application. For example, computer A on the application to send information to the computer application B, then A computer application in information need to be sent to the Application Layer（seventh layer）, and then this l

32、ayer will be sent to that level of information（sixth floor）, indicating that the data layer will be transferred to the session layer（fifth layer）, and so continue until the physical layer（first layer）. In the physical layer, data is placed in the physical network media and sent to computer B. The ph

33、ysical layer of computer B to receive data from the physical media, and then send information up to data link layer（second layer）, data link layer and then to the network layer, until the information in order to arrive at the application layer of computer B. Finally, the application layer of compute

34、r B and then the application information to the receiving end, thus completing the communication process. The following describes the icons in the process. OSI's seven control the use of a wide range of information and other computer systems to communicate the corresponding layer. Control inform

35、ation contained in these special requests, and show that they correspond to the OSI layer exchange. Data at every level of the head and tail to bring the two basic forms of control information. For one to send down from the previous data, additional control information in the front as the head, atta

36、ched to the back of the end of the control information is called. However, data from one level to increase the agreement and the agreement the end of the first of a OSI layer is not necessary. When the data transmission between each floor, each level in the data can be added to the head and tail, an

37、d these data have been included to increase the level of the head and tail. Agreement includes the first layer and the communication of information between layers. Head and tail as well as the data is associated with the concept, they depend on the analysis of the protocol layer module. For example,

38、 the transport layer header includes only the transport layer can be seen the information, the transport layer of the other layers below this only the first part of a data transmission. For the network layer, an information unit from the third layer composed of the first and data. The data link laye

39、r, network layer by passing down all the information that is the first and third data layer is seen as data. In other words, a given OSI layer, the information unit that contains the data from all parts of the upper head and tail, as well as data, referred to as packaging. For example, if computer A

40、 to a certain application data sent to computer B, the first data sent to the application layer. A computer in the application layer protocol data to add up and the application layer of computer B communications. Formed by the first information unit includes an agreement, data, and possibly the end

41、of the agreement was sent to that layer, that layer of computer B and then add that layer of the control information to understand the agreement first. Information on the size of units in each level in agreement with the agreement the end of the first and add the increase in the first of these agree

42、ments and agreements contained in the computer B the end of the corresponding layers of control information to be used. In the physical layer, the entire information unit through the network transmission medium. Computer B in the physical layer unit of information received and sent to the data link

43、layer; and B data link layer in computer A to read the data link layer protocol header added to the control of information; and then remove the agreement and the end of the first agreement, sent to the remainder of the network layer. Perform the same at every level of action： from the corresponding

44、first layer to read the agreement and protocol tail, and remove, and then send the remaining first floor. End of application-layer implementation of these actions, the data sent to computer B on the application, the data and computer applications A is exactly the same as sent. An OSI layer and anoth

45、er layer of communication between the second layer is the use of the services completed. Services provided by adjacent layers help a OSI layer with another layer corresponds to the computer system to communicate. A particular layer of the OSI model is often associated with three other OSI layers con

46、tact: with the layer directly adjacent to and under the floor, as well as the objectives of the corresponding computer systems networking layer. For example, computer A's data link layer should be with the network layer, physical layer of computer B, as well as the data link layer communication.

47、 附錄B為了讓電腦來溝通，就必須講同樣的語言或議定書。在早期的網(wǎng)絡(luò)化，網(wǎng)絡(luò)松散，在很多方面。公司開發(fā)了專有的網(wǎng)絡(luò)技術(shù)，有很大的困難，交流信息與其他的或現(xiàn)有的技術(shù)，使網(wǎng)絡(luò)互連非常辛苦建立的。為了解決這個(gè)問題，國際標(biāo)準(zhǔn)化組織（ISO）建立了一個(gè)網(wǎng)絡(luò)模型，可以幫助制造商網(wǎng)絡(luò)彼此兼容。發(fā)現(xiàn)最佳的軟件不容易。對什么的更好的理解您需要并且問合適的問題使它更加容易。軟件應(yīng)該是能處理挑戰(zhàn)具體對您的公司。如果您操作多個(gè)分配中心，它也許是有利創(chuàng)造路線與產(chǎn)品起源于超過一個(gè)集中處。少量軟件提供者雖則，是能優(yōu)選路線使用多個(gè)集中處。提供者應(yīng)該能支持它的產(chǎn)品的設(shè)施。保證清楚地了解什么訓(xùn)練和軟件維護(hù)被提供。明顯地，選擇正確的

48、發(fā)送預(yù)定的軟件重要地重要。不幸地，一些公司使用不能是適合對他們的操作的軟件。最大限制的對批準(zhǔn)軟件的責(zé)任應(yīng)該是舒適的他們做出了正確的決定。它重要意識到?jīng)]有所有發(fā)送預(yù)定的軟件是假象！其它問題要求是： 哪個(gè)操作系統(tǒng)被使用？ 多么容易軟件使用？ 這一個(gè)好方式知道。問如果它的圖形用戶界面（GUI）是靈活的。發(fā)現(xiàn)關(guān)于設(shè)施速度- 多長時(shí)間需要？ 軟件能尋址第三方顧客以您的核心業(yè)務(wù)嗎？ 何時(shí)軟件最初被發(fā)布了并且何時(shí)這是為時(shí)被升級？在1984年，國際標(biāo)準(zhǔn)化組織公布的開放系統(tǒng)互連（OSI）以參考模型，這是一個(gè)清楚界定的一套技術(shù)規(guī)范，保證了更大的兼容性，各方面的技術(shù)。事實(shí)上，在OSI的是一個(gè)描述網(wǎng)絡(luò)通信的每個(gè)人都指

49、。它并非是唯一的網(wǎng)絡(luò)模型，但它已成為主要模式，為網(wǎng)絡(luò)通信。你會看到進(jìn)一步在這一章中，認(rèn)為TCP / IP的模式只是一種降低版本的OSI模型。OSI模型共分七層，每個(gè)說明某一特定的網(wǎng)絡(luò)功能。表示層的目的定義了數(shù)據(jù)代表的數(shù)據(jù)格式。數(shù)據(jù)格式通常是象ASCII、JPEG、GIF、TIFF、MPEG等等開放系統(tǒng)互連層6的標(biāo)準(zhǔn)格式也定義了加密作為表示層服務(wù)。定義數(shù)據(jù)格式的The重要性是顯然的。例如，當(dāng)送電子郵件時(shí)，您通常送它純文本（ASCII）或HTML。如果接受應(yīng)用不知道這些數(shù)據(jù)格式，您的電子郵件不會恰當(dāng)?shù)乇伙@示。OSI層數(shù)6為上部開放系統(tǒng)互連層（應(yīng)用）提供一項(xiàng)服務(wù)。它格式化在間網(wǎng)絡(luò)有些將被送的數(shù)據(jù)接受

50、應(yīng)用能了解并且/或者操作。如，編程人員在設(shè)計(jì)圖像編輯器軟件時(shí)，就無需將應(yīng)用層功能添加到該軟件中，因?yàn)樵撥浖ぷ鲿r(shí)無需與其它計(jì)算機(jī)進(jìn)行通信。但在創(chuàng)建FTP客戶端程序時(shí)，就必須在該軟件中加入通信功能。應(yīng)用層協(xié)議一般有Telnet、 FTP、 HTTP、SMTP、SNMP和SSH等。應(yīng)用層過濾一般只是指過濾應(yīng)用數(shù)據(jù)，而與數(shù)據(jù)來源的端口和主機(jī)無關(guān)。OSI將計(jì)算機(jī)網(wǎng)絡(luò)體系結(jié)構(gòu)（architecture）劃分為以下七層：第一層：物理層（Physical Layer）規(guī)定通信設(shè)備的機(jī)械的、電氣的、功能的和過程的特性，用以建立、維護(hù)和拆除物理鏈路連接。具體地講，機(jī)械特性規(guī)定了網(wǎng)絡(luò)連接時(shí)所需接插件的規(guī)格尺寸、引

51、腳數(shù)量和排列情況等；電氣特性規(guī)定了在物理連接上傳輸bit流時(shí)線路上信號電平的大小、阻抗匹配、傳輸速率距離限制等；功能特性是指對各個(gè)信號先分配確切的信號含義，即定義了DTE和DCE之間各個(gè)線路的功能；規(guī)程特性定義了利用信號線進(jìn)行bit流傳輸?shù)囊唤M操作規(guī)程，是指在物理連接的建立、維護(hù)、交換信息是，DTE和DCE雙放在各電路上的動(dòng)作系列。在這一層，數(shù)據(jù)的單位稱為比特（bit）。屬于物理層定義的典型規(guī)范代表包括：EIA/TIA RS-232、EIA/TIA RS-449、V.35、RJ-45等。第二層：數(shù)據(jù)鏈路層（Data Link Layer）在物理層提供比特流服務(wù)的基礎(chǔ)上，建立相鄰結(jié)點(diǎn)之間的數(shù)據(jù)鏈

52、路，通過差錯(cuò)控制提供數(shù)據(jù)幀（Frame）在信道上無差錯(cuò)的傳輸，并進(jìn)行各電路上的動(dòng)作系列。數(shù)據(jù)鏈路層在不可靠的物理介質(zhì)上提供可靠的傳輸。該層的作用包括：物理地址尋址、數(shù)據(jù)的成幀、流量控制、數(shù)據(jù)的檢錯(cuò)、重發(fā)等。在這一層，數(shù)據(jù)的單位稱為幀（frame）。數(shù)據(jù)鏈路層協(xié)議的代表包括：SDLC、HDLC、PPP、STP、幀中繼等。第三層：網(wǎng)絡(luò)層在計(jì)算機(jī)網(wǎng)絡(luò)中進(jìn)行通信的兩個(gè)計(jì)算機(jī)之間可能會經(jīng)過很多個(gè)數(shù)據(jù)鏈路，也可能還要經(jīng)過很多通信子網(wǎng)。網(wǎng)絡(luò)層的任務(wù)就是選擇合適的網(wǎng)間路由和交換結(jié)點(diǎn)，確保數(shù)據(jù)及時(shí)傳送。網(wǎng)絡(luò)層將數(shù)據(jù)鏈路層提供的幀組成數(shù)據(jù)包，包中封裝有網(wǎng)絡(luò)層包頭，其中含有邏輯地址信息- -源站點(diǎn)和目的站點(diǎn)地址的網(wǎng)

53、絡(luò)地址。如果你在談?wù)撘粋€(gè)IP地址，那么你是在處理第3層的問題，這是“數(shù)據(jù)包”問題，而不是第2層的“幀”。IP是第3層問題的一部分，此外還有一些路由協(xié)議和地址解析協(xié)議（ARP）。有關(guān)路由的一切事情都在第3層處理。地址解析和路由是3層的重要目的。網(wǎng)絡(luò)層還可以實(shí)現(xiàn)擁塞控制、網(wǎng)際互連等功能。在這一層，數(shù)據(jù)的單位稱為數(shù)據(jù)包（packet）。網(wǎng)絡(luò)層協(xié)議的代表包括：IP、IPX、RIP、OSPF等。第四層：是處理信息的傳輸層第4層的數(shù)據(jù)單元也稱作數(shù)據(jù)包（packets）。但是，當(dāng)你談?wù)揟CP等具體的協(xié)議時(shí)又有特殊的叫法，TCP的數(shù)據(jù)單元稱為段（segments）而UDP協(xié)議的數(shù)據(jù)單元稱為“數(shù)據(jù)報(bào)（datagrams）”。這個(gè)層負(fù)責(zé)獲取全部信息，