The mesh. "Shu-Chuan Xue Wei is": "Home funeral car, without carving, but the use of hemp as tassels, cords with the network only." Tandoori treasure "the great cause of miscellanies": "﹝ ﹞ its dry sun house big 20 column round, leaning well vertical Lin, Yao Yang of those dizzy. Xuān vertical bead wire network to seven feet under is not to prevent the birds. "
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No. 3
Analogy Act. "Han Po-Young Biography": "Network Zhang located less love interest, the courage to Heaven's." Ming Tang Shun the "gift of Yixing Yinlin Jun order": "Officials who see the people after the RAO to the stupid stupid cage too easily, Illegal Fishing is more than one network, thus, the livelihood of the people to Satan Organisation and the Japanese puppet of issues concerning rape. "Qing Hua Tang Sun," donated the same year, Zhao Meng Quan "Poetry:" shackles Chen Five Penalties, seven follow-up network facilities. "
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No. 4
Enlist; summary. Sima Zhen Tang "fill <Historical Records> order": "Of course its network past and present, narrative Correctional advised, Zuo different micro-wan, a History of Southern Dynasties of the Code of reality." Cao Yu "My life and creative path": "Bailu Chen is the main line, by her story and those characters collusion, the network up. "
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No. 5
Circuit or a part of the general. Many network classification: according to the internal parameters (resistance, inductance and capacitance) with the current (or voltage) whether the size and direction of change, divided into "nonlinear network" and "linear network"; according to whether they contain an internal power supply ( such as batteries, valves, etc.), divided into "active networks" and "passive network"; by protruding from the number of terminals is divided into "two-terminal network" and "port networks," and so on.
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No. 6
① refers to things like network or network system: distribution network. ② Tezhi the circuit made by the electronic system: transmission network.
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No. 7
Network ([electrics] [computer] a network)
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Network concept
Network: General English translation: internet or network. To put it simply, is to use physical link to workstation or host various isolated linked together to form a data link to achieve the purpose of resource sharing and communication. Where a different location and function of the number of independent computer systems through the communications equipment and wiring and connected, and the functional network software (network protocols, information exchange and network operating systems, etc.) to share network resources system can be called a computer network. There are many words meaning the network can be interpreted as: 1, the flow network (flow network) is also referred to as network (network). Generally used on the pipeline system, transportation systems, communication systems modeling. Sometimes refers specifically to the computer network (computer network), or especially one of the internet (internet) by a system composed of related individuals, such as: social networks, transportation network, political network. Computer network is communication lines and communication equipment will be distributed in different locations of multiple autonomous computer systems connected to each other, according to a common network protocols, shared hardware, software and data resources system. To achieve the four elements of the network: 1, communications lines and communications equipment 2, a separate computer functions 3, network software, software support 4, data communication and resource sharing
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Stage of development of computer network
Online remote terminal stage Stage of the computer network (LAN) Stages of computer networking (WAN, internet) Information superhighway stage (high-speed, multi-service, large data)
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English Description
in general, the term network can refer to any interconnected group or system. several different types of networks exist, including: 1. Human networks [business network; entrepreneurial network; social network; economic network; old boy network; sexual network] 2. Media radio network, create and distribute radio programming through multiple channels that connect in a network television network, create and distribute television programming through multiple channels that connect in a network network (film), an academy award winning film from 1976 nettwerk, a record label the network, a band network (comics), a name given to several marvel comics super heroes network (computer game), an economic simulation for the apple ii personal computer 3. Technology electrical network, a network of electrical components computer network, a network of computers computer networking, the scientific and engineering discipline concerned with this kind of network telecommunications network, a network of telecommunications links energy transmission and distribution networks electric power transmission network, a network of conduits for bulk transmission of electric power electricity distribution network, a network of conduits for delivery or short-haul transmission of electric power pipeline transport network, a network of pipes for transmission of gases, usually natural gas gas distribution network, a network of pipes for delivery of gases, usually natural gas or, formerly, town gas network systems system network, a system of combined networks of main systems 4. Science, mathematics, and engineering network theory, the applied mathematics counterpart of graph theory, especially in combinatorial optimization flow network, an assignment of flow to the edges of a directed graph where each edge has a capacity network (mathematics), a type of diagraph in graph theory neural network, an interconnected group of biological neurons artificial neural network, an interconnected group of artificial neurons 5.other transport network, facilities on which people and goods move spatial network, urban networks or networks of rooms within buildings network effect, a characteristic that causes a good or service to have a value to a potential customer dependent on the number of customers already owning that good or using that service network (catholic lobby), a national catholic social justice lobbying group based in washington, dc.
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Computer network development
The first generation: a remote terminal connection The early 20th century, 60 Terminal-oriented computer network: the host is a network of centers and controllers, terminals (keyboard and monitor) and distributed throughout the host is connected, the user terminal through a local host using the remote. Provides only communication between the terminal and the host, can not communicate between subnets. The second generation: computer network stage (LAN) The mid-20th century, 60 Multiple host connectivity, to achieve communication between the computer and the computer. Include: communication subnet, the user resource subnet. End users can access the local host and all hosts subnet communications hardware and software resources. Circuit switching and packet switching. Third Generation: computer networking stage (wide area network, internet) 1981 International Organization for Standardization (iso) formulation: Open System Interconnection Basic Reference Model (osi / rm), realized between different manufacturers of computers interconnected. tcp / ip protocol was born. The fourth generation: the information highway (high-speed, multi-service, large data) Broadband Integrated Services Digital Network: Information Highway atm technology, isdn, Gigabit Ethernet Interactive: online TV on-demand, videoconferencing, video telephony, online shopping, online banking, high-speed network library, visualization.
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History of the development of computer network
In fact, internet has come early age, but limited to the connection speed and cost, a lot of people do not really able to make full use and enjoy it. Today, a variety of connection methods and connection speeds faster and faster so that people can enjoy a good broadband network (broadband networking) and the impact to our life, study the impact of work, let us live really live, work and enjoy in a broadband era! Broadband network in the learning, we need to look at the history of the network, for us to understand and use the network of great benefit! One, internet useful internet computers around the world to communicate with each other ways and means of information carrier and delivery systems, the link connecting the computer world, but also a powerful "tool." Is the world's largest computer network, covering almost the entire range of the world, it _set_s information, communications, entertainment, resource sharing in one of modern society the exchange of information highway. Enterprises not only can be obtained from the large amount of business information online, but also to the international community through the internet to show themselves. Is the coverage of the world's largest, most users, the most abundant resources, the most practical computer network. internet information content is very large, we can not only treat it as a computer network, and make it as a large, practical, and can enjoy the source of information. We also want you to internet as a mob-oriented society to understand that millions of people around the world use the internet to communicate and share information sources. Can send or receive e-mail communications; to establish contact with others and with each other requests for information; available online announcement, promote your information; can participate in group discussions on various topics; free access to a wealth of information sources and software resources. Second, internet development history With the 1946, the world's first electronic computer than a decade after the advent of time, because the price is very expensive, very few computers. Early so-called computer network is mainly to solve this contradiction arising in the form of a computer through the communication line directly connected with a number of terminals, we can also see this approach as a simple LAN shape. The first internet, by the U.S. Defense Advanced Research Projects Agency (arpa) established. Many of the concepts of modern computer networks and methods, such as packet switching technologies are from the arpanet. arpanet internet leased lines were not only the packet switching technology, and do wireless, satellite, packet-switched technology - the result of the tcp / ip published. Third, China's internet 1, internet phased development China's internet development to 1987 by the Chinese Academic Network canet first letter to the world as the symbol e-mail. After several years of development, the formation of the four major network systems, namely: Chinese Academy of Science and Technology Network cstnet; the Ministry of Education Education and Research Network cernet; the former Ministry of Posts and Telecommunications and the former Ministry of Electronics chinanet the Golden Bridge Network chinagbn. Development of internet in China can be roughly divided into three stages: The first phase 1987-1993, and also research and test phase. During this period some of China's scientific research departments and institutions of higher learning began to study internetinternet technology, and carried out research projects and scientific and technological cooperation, but at this stage of the network application is limited to a small range of e-mail service. The second stage is from 1994 to 1996, the same initial stage. April 1994, Zhongguancun area network engineering education and research and demonstration into the internet, an official from China was internationally recognized as a national internet. After, chinanet, cernet, cstnet, chinagbnet other internet network across the country have launched projects, internet began to enter public life, and in China have been developing rapidly. The end of 1996, China has reached 20 million internet users, the use of internet services and applications carried out by gradually increasing. The third stage, from 1997 to the present, is the fastest internet in the stage of fast. Domestic internet users remained 97 years later to double the growth rate every six months. Growth to today, has more than 10 million Internet users. According to the China internet Network Information Center (cnnic) published a statistical report, as of June 30, 2003, the total number of Internet users in China is 6800 million. Beginning of the year this figure increased by 890 million, compared with the same period in 2002 increased by 2220 million. China currently has five lines of furniture have independent international import and export of commercial units of the internet backbone, as well as for education, science and technology, trade and other areas of non-profit internet backbone units. There are more than 600 Internet access service providers (isp), of which there are 140 inter-provincial business. With improvements in network infrastructure, user access aspects of new technologies, eight-way access and carrier services to the diversification of capacity, slow rate of formation of the access network bottleneck will be further improved, Internet speed will be faster to promote the realization of more applications on the Internet. 2, the future focus of development Despite such good results, but the Government is on the focus of future development of Chinese internet made arrangements to see them live on our broadband future is very useful: (1) According to the State Council has promulgated the "Telecommunications Regulations" and "internet information services management approach" regulations amend the existing network management and continuous improvement based on the actual network development and the development of new regulations; (2) expand the network scale, optimize network structure, avoid duplication and enable the network to an integrated, broadband, intelligent development; (3) in the basic network, the introduction of competition mechanism to further promote lower prices, improve services and solve the bandwidth of the bottleneck constraint satisfaction network development; (4) full use of social resources, such as libraries, public database, rich Internet content in Chinese; (5) To attach great importance to network security issues. Currently, the domestic has been a number of universities and research institutions specializing in research projects, some results have begun to use; (6) to strengthen China and the international network of industry contacts. China Education and Research Department has already begun on the next generation of internet and foreign cooperative research. The first generation of internet mainly by foreign research and development, China late start, but through the efforts have gradually narrowed the distance between the international level; Fourth, internet opportunities and challenges Internet development in China, there are still some other problems. First, the Chinese internet and abroad there is a gap. The total number of the user, the current global Internet has been more than two hundred million, half in the United States, Canada, UK, Japan and other countries are ahead of the number of netizens in China. But the agency has been predicted that in the next few years, the number of Internet users in China will be largest in the world top five, and even the top three, because China's population base is too large, so the penetration rate of Internet users is still very low. Canada, the United States and Japan, Internet users penetration reached 30%, while China only has 1.4%. Second, the scale of China's network from the network there is a big gap between the developed countries. But with the increase in infrastructure, the use of broadband technology, there will be steady in the network scale development. Third, China is also lagging behind network management and regulations and is not perfect, according to the state has promulgated the "Telecommunications Regulations" in the revision of existing departmental regulations suited to the part of the new requirements for new business development, so that laws and regulations in place. Fourth, because of language and concepts of reason, the Chinese Internet information resources need to work harder. In addition, the Chinese Internet industry in capital investment, business model, philosophy, technology innovation, requires in-depth thinking and research. Some of the foreign way of success may not necessarily work in China, it is not copied, the development pattern of China's national conditions. cmwap access refers to the wap network access gateway, intelligent browsing wap site, cmnet internet browser can access the page www. (1) two access points Internationally, gprs access is usually only one way, why would China cmwap and cmnet two brothers? (MMS access point configuration is the reason why the individual services need to be connected because the MMS dedicated server, not to discuss here) In fact, cmwap and cmnet by only two people of China Mobile gprs access. The former is established cell phone wap access, and the latter mainly for the pc, laptops, pda and other Internet services using gprs. They realize there is no difference in the way, but because of positioning different than so and cmnet, cmwap will have some restrictions, tariffs, there are also differences. (2) wap gprs wap application is only a model, it grps access mode is irrelevant. wap application using the implementation is "Terminal + wap gateway + wap server" model, different from the general internet's "Terminal + server" mode. The main purpose is to be completed by wap wap-web gateway protocol conversion in order to achieve savings in network traffic and the purpose of compatibility with existing web applications. wap gateway from a technical point of view, just a host to provide agency services, it is not necessarily provided by the network operator. But as far as I know, China Mobile gprs network currently has a single wap gateway: 10.0.0.172, with China Mobile to provide for the wap browser (http) service. One thing to note, wap gateway and the LAN gateway on a general sense there is a difference, the standard wap gateway http proxy only implements the function, did not complete the routing, nat and other local area network gateway functionality. This is determined by its restrictions on the application. (3) China Mobile, the restrictions on cmwap In order to distinguish the two from the application of positioning, China Mobile made certain restrictions on the cmwap, mainly in cmwap can only access the gprs access within the network ip (10 .*.*.*), can not access through the route internet. (A few areas of the mobile network may not exist in this limit) we cmwap browse internet pages on the wap gateway is through the http protocol, or it provides agency services to achieve. Here, let me naturally to think of our company's network, I believe a lot of work friends have similar experiences. The company's network at the gateway does not provide routing and nat, just to provide an http proxy to access outside the network. In this way, we can not directly use qq, msn and other non-http protocol applications of (Fortunately, they also provide a http proxy connection.) It is also cmwap (4) Scope We are most concerned about is the scope of the problem. cmnet have full internet access, here is not to say, let's look at the main cmwap. Because of the restrictions mentioned above, cmwap depends on the application of wap gateway provides support. Currently, China Mobile's wap gateway outside agency agreement only http (port 80 and 8080) and the wap gateway protocol (port 9201). 【China】 four backbone China Public Computer Internet (chinanet) Ministry of Posts and Telecommunications, also known as the Internet, the Chinese public internet network, the Ministry of Post and Telecommunications and internet-based network management technology, electronic information network, connectivity with the Internet in early 1995, and in May to provide services to the community. chinanet by the backbone network, access network composed of backbone networks is the main information channel, from cities and municipalities and provinces will constitute a network node; access network in the provinces (regions) to build a network of network contacts. chinanet flexible access methods and cities across the country access point, you can easily access the international internet, access to a wealth of information on internet resources and services, and for the domestic computer interconnection, sharing of information resources for domestic provide a convenient network environment. China Education and Research Network (cernet) Launched in 1994, completed the first phase of the end of 1995, including Beijing (Network Center), Shanghai, Nanjing, Guangzhou, Wuhan, Xi'an, Chengdu and Shenyang higher concentration of large cities. America's international line is connected. National Backbone Network (a total of 11 64kbps ddn line) opened in October 1995. Phase II is completed, the national backbone and international networking escalation to 2kbps more backbone, international networking to achieve 8kbps above. China Science and Technology Network (cstnet) Presided over by the Chinese Academy of Sciences, the United Tsinghua University, Beijing to jointly build. April 1994 opening of the line with internet connection. May 21, 1994 completed a master of the highest cn domain name server _set_tings, to achieve with the internet's tcp / ip connection. Basically completed the end of 1995, "one hundred network" project. The end of 1997, has more than 100 Ethernet connections, more than 3,000 computers, more than 1 million users, a wide area of China, use large, performance, communication capacity, service facilities of the national research and education network. China Golden Bridge Information Network (chinagbn) The national public economic information network, the former Ministry of Electronics Industry Management, for the government, enterprises, institutions and the public to provide data communications and information services. Golden Bridge Network and internet connectivity by the end, has opened 24 cities, the development of more than 1,000 local and remote terminal emulation to provide comprehensive internet service.
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Network classification
Press coverage points: LAN lan (scope typically a few meters to tens of kilometers) MAN man (between the circles in the wan and lan) WAN wan (scope typically tens to thousands of kilometers) Classification by topology BUS Ring Star Mesh By way of exchange of information points: Circuit switching Message switching Packet switching A network can be composed of two computers, but also in the same building which can have thousands of computers and users. We usually refer to such networks as the local area network (lan, local area network), extending out from the lan and then a larger area, such as entire cities and even entire countries, such a network we call the wide area network (wan, wide area network), of course, you If the case by carefully again, you can have man (metropolitan area network) and can (citywide area network), these networks need to have a dedicated management staff for maintenance. The most we can touch the internet is from these numerous composed of lan and wan. internet provides the only connection between them, but no specific person to manage (in addition to maintain the connection and the development of use of standards), can be said that internet is the king of the freest and most did not control the place. In the internet has no borders and above the points race, as long as even up, the other side of the planet and your roommate's computer, the computer is no different in fact. Because we are still the most commonly used lan, (even if we connected from home internet, is actually the first connected to the isp's lan), so here we focus on the main thing is to lan. lan network which can be said that the basic unit of many, and so you have a certain understanding of lan, wan to go to understand and easier to start with the internet, but need to understand more complex means of communication only. Network of friends and contacts, more or less above the number of terms should be heard, right? However, we know the difference between them and how to define it? In fact, the term should be the earliest internet, and then people will introduce concepts and techniques of internet to the internal private network, which can be a stand-alone can also be a dedicated lan wan, so he called the intranet of the. The biggest difference between them is: open. internet is open, does not belong to anyone, as long as you are connected by a member, it can get above the open resource; relatively speaking, intranet is the exclusive, non-open, it often exists in the over private networks, but its structure and service methods and design, are for reference only internet model.
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internet vs intranet
As for the extranet, intranet and can be regarded as an extension for the concept out. Since the intranet is the internal network of the Ministry, the then extranet refers to the external network. extranet and internet connections are usually enterprises to provide services to the public network. However, this is not simply based on the definition of physical or logical location, mainly in connection to distinguish between form and function. For example, an external network, if a simple network connection through our extranet or intranet, then it is only a relevant external individuals without it; but if we trust or other form of vpn link up each other, then the other side also can belong to extranet or internet part. In the history of mankind, the emergence and development of computer has a long history. However, as the carrier of the Internet to the computer, I do not know when to start, quietly entered, and into our lives. The development of modern society, the Internet has reached an unprecedented height of dependence. Network, has brought a strong and powerful transmission, and greatly reduced the time for information release and receive, to avoid unnecessary waste of resources. Networks, greatly narrowed the distance between people. As we all know, the game on the network continues to grow, more and more game categories. Take our most contact oicq example. Many friends because of the distance of time and space, often in reality there is no way to contact. qq to friends to be in these situations provide a good liaison channels. In the qq, not only old friends can contact, you can also meet many new friends. In a short chat and communication, so narrow the gap between people's hearts. In other various online games, people can also be the game of mutual cooperation, mutual help, knew them, and became a good friend of utter devotion. People can also e-mail correspondence in the online, inform each other well. Sars rampant in recent months, regional disease vary. In a serious epidemic in Hong Kong and Beijing, there are numerous number of the students suspended. Students in the class suspension period in the education sector is to use the network on the Internet offering "air classroom", provides students with basic academic questions and exercises exercises, so students can normally learn at home, and learn new ways to attract more students Note also improve students interest in learning. Similar in many other teaching distance education also has application. As we have now a senior study, because some students have to go out to work, can not return to school to participate in the remaining courses. But whether in school or do school work, final examination must be performed. In order to facilitate students absent teacher, put notes on the web so that students easily self. Not only education and learning, trade, meetings, etc. can also be made online. "Net meetting" The term is widely popular in the network. Different countries, different regions of the businesses, companies can network through the network meeting to coordinate and discuss important business issues, save the convening of participants, agreed that the meeting time and place a series of complicated procedural steps, save a lot of manpower material resources. However, the network has brought us many benefits, but also brought a number of shortcomings. First, the Internet's rapid development has brought to the unscrupulous traders can take advantage drilling. A lot of sex, violence, gambling and other bad sites came into being. These unscrupulous traders to reap huge profits, regardless of the site information for young people thinking of how much harm the health, keep profits in the transmission of pornographic Web site information. What is more obscene films of different manufacturers, requiring visitors to view the first payment. In addition to pornographic sites profits, and some sites in which to _set_ the phone's charging system, once the viewer to open its web browser, you will be charged unreasonable and expensive long-distance telephone charges, so that visitors suffered huge economic losses. There are many on the network to work, personals, marriage intermediary site, but which also lack cheat money, no obligation website. Internet users who are not careful, you will step into these carefully laid trap. Secondly, the network has brought a lot of disputes between people. Because for the network, the Government introduced the policy is not perfect, so there are many issues on intellectual property generated in the steady flow. For example, some articles available online after being repeatedly copied, modified, satisfied that there has been re-released as a serious violation of the original author's copyright. However, due to the complicated network, uncertainty, and often can not find the source of plagiarism adaptation. Another example is the game we have in the network's account, sometimes unauthorized use, it is also a criminal, but we often because they can not do nothing leaving thieves. Game account or small, is important if the stolen commercial information, the relevant disclosure of commercial secrets, theft of companies that will result suffered serious losses. If the theft of state secrets, then the consequences even more disastrous. The country's military and defense systems may have been devastating, even incalculable human and material resources to spend to re-establish on the military aspects of the data. Network to bring people not only ideologically invisible injury, the health of many users also caused damage can not be ignored. Once on television many times we see this report: certain young people for too long as playing online games, resulting in lower body suddenly paralyzed, unable to move, there is shock and coma in severe examples. As the computer for the human body radiation, if the person sitting in front of the computer for a long time of inactivity to very easily lead to all kinds of unpredictable physical harm. The most significant is that for the vision impaired. The statistics, people who work in a long time computer vision is generally little contact with computers than the sight of people a lot worse. Network, to bring immeasurable convenience, opportunity, wealth, but also gave rise to many potential crises can not be expected. Network, is really a place where people love to hate.
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Network Security
Network security is a matter of national security and sovereignty, social stability and develop national culture, the important issue of succession. Its importance as the global information technology are accelerating the pace of change to the more important. "The house is the door," security imperative. Network security is one related to computer science, network technology, communication technology, cryptography, information security technology, applied mathematics, number theory, information theory and other disciplines, comprehensive discipline. Network security refers to the network hardware, software and data in the system are protected from accidental or malicious destruction of reasons, change, disclosure, continuous and reliable system to run properly, the network service is not interrupted. Network security is its essence on the network information security. Broadly speaking, any information relating to the network confidentiality, integrity, availability, authenticity and control technologies and theories are related to network security research field. Network security will be with the specific meaning of "perspective" and change. For example: from the users (individuals, businesses, etc.) point of view, they want privacy or commercial interests involving personal information in the network transmission by the confidentiality, integrity and authenticity protection, to avoid other people or competitors to use listening, impersonation, tampering, repudiation and other means of violating the interests of users and privacy, access and destruction. From the network operation and management perspective, they want access to information on the local network, read and write and other operations are protected and controlled, to avoid a "trap door", viruses, unauthorized access, denial of service and network resource control of illegal occupation and illegal and other threats, stop and defense network hackers. Of the security sector, they want to illegal, harmful or information involving state secrets to filter and blockades, to avoid disclosure of confidential information and avoid harm to society, causing great loss to the country. Education and ideology from the social point of view, unhealthy content on the network, will social stability and obstruct human development and must be controlled.
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Internet Language
Internet language is accompanied by the development of the emerging network is different from traditional print media as a form of language. It is a lively form of a concise soon as he was born to be a preference for the majority of users, developed rapidly. Web languages including phonetic alphabet, or the abbreviation. Contains a specific number, and a vivid sense of network automation and pictures, at first mainly Wangchong Men to improve the efficiency of online chat or a particular approach to the needs of the passage of time to the formation of a specific language. New terms emerge on the network depends mainly on its own vitality, if the dynamic network of language can stand the test of time, can be accepted after the convention.
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VoIP
Internet phone (web phone), also known as ip phones, it is through the Internet Protocol (internet protocol, ip) for voice transmission. The traditional way of international calls is to transmit the analog voice signal is converted to the first, the sound transmitted through the copper to each other. Sucked through the telephone network voice gateway (gateway) is converted to data signals, and is compressed into data packets (packet), then sent out from the Internet, the receiver receives a packet, the gateway will extract it, sound re-converted to the other to listen. In general the current Internet phone-line can be divided into three kinds: pc to pc, pc to phone, phone to phone. Internet telephony is a revolutionary product, it can be done through the Internet in real-time transmission and bilateral dialogue. You can through local Internet service provider (isp) or telephone company to the cost of local telephone call charges to other networks around the world phone users. From office workers to home users, students, Internet surfers, gamers and grandparents, who, VoIP provides a completely new, easy, economical way to and around the world, friends and colleagues call.
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Network TV
iptv that IPTV is a broadband infrastructure for the use, computer (pc) or "normal TV + network _set_-top box (tv + ipstb)" as the main terminal device, to provide users with video on demand, internet access, e-mail , games and other interactive digital media services to individual needs of new technology.
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Online Education
Online education refers to the network environment, with modern educational thinking and learning philosophy as a guide, give full play to the network features and rich variety of educational resources online education, educators and learners to provide a network of teaching and learning service, the service is reflected in the delivery of content with digital technology. Carried out by non-face learner-centered education.
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Network Finance
The so-called network of financial, also known as e-finance (e-finance), refers to the Internet (internet) to achieve the financial activities, including the network of financial institutions, Internet financial transactions, networks, and network financial supervision of financial markets and so on. It is different from the traditional to the physical form of existence of financial activity, is present in the financial activities in the electronic space, whose existence is a form of virtualization, the operating mode is networked. It is information technology, especially the product of the rapid development of Internet technology, is to adapt to electronic commerce (e-commerce) development needs arising from the financial operation mode of the Internet age.
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Internet Insurance
Insurance is an emerging network of computer networks as a medium of insurance marketing model, are different from traditional insurance agent marketing. Emergence and development of network insurance is a historical trend, it represents the direction of the international insurance industry. At present, the insurance web site can be divided into two categories: The first is the insurance company self-built website, mainly to promote their own insurance, such as the Ping An Insurance's "pa18", Taikang Life Insurance's "Tai-line" and so on; second is an independent third-party insurance Web site by the professional Internet service provider (isp) funded the establishment of the insurance site does not belong to any insurance company, but also provide insurance services, such as easy security, network insurance. Obviously, these two categories of sites represent the level of development of China's Internet Insurance, when the implementation of their strategies and market operation of a rational, objective research and analysis, will be able to deeply grasp the development of the insurance network. Network insurance is a huge social systems engineering, related to banking, telecommunications and other industries, this project takes a long time to complete. Hackers attack computer network systems that currently lack their own security protection, Internet Insurance insecurity risks; and the network between the parties to the insurance because the insurance and the profound complexity of human factors background and interests, making the online complaints, claims likely to breed fraud. Therefore, the operation is difficult to rely solely on online support network insurance. How to prohibit and punish the use of network behavior of the insurance for insurance fraud? How to implement online underwriting and claims and payment online? Internet Insurance in China is still a long way to go. Internet Insurance technology research by the National Science and Technology R & D personnel package of "security reinforcement system," the security of the server maintenance, resistance to hackers, viruses and worms invasion. Deadline December 7, 2007, the Central News Network to broadcast a new generation of "security reinforcement system" has been put into operation. Commonly used in computer network communications equipment: Hubs, repeaters, bridges, switches, routers, gateways and so on.
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Network concept
Network, simply, is to use physical link to workstation or host various isolated linked together to form a data link to achieve the purpose of resource sharing and communication. Where a different location and function of the number of independent computer systems through the communications equipment and wiring and connected, and the functional network software (network protocols, information exchange and network operating systems, etc.) to share network resources system can be called a computer network. There are many words meaning the network can be interpreted as: 1, the flow network (Flow Network) can also be referred to as the Network (Network). Generally used on the pipeline system, transportation systems, communication systems modeling. Sometimes refers specifically to computer networks (Computer Network), or especially one of the Internet (Internet) by a system composed of related individuals, such as: social networks, transportation network, political network. Computer network is communication lines and communication equipment will be distributed in different locations of multiple autonomous computer systems connected to each other, according to a common network protocols, shared hardware, software and data resources system.
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The birth of the network
The birth of the network mission: through a variety of Internet services to enhance the global quality of human life. Network for human life more convenient and rich, thus contributing to the global progress of human society. And enrich our spiritual world and physical world, so that human beings the most convenient access to information, find what we seek to make human life happier. In contrast with the imagination of many people, Internet is not the result of a perfect plan, Internet's founders would never think it can develop into the current size and influence. Internet available in the beginning, no one can think of it in every household, no one can think of it for commercial purposes. In 1983, ARPA and the U.S. Department of Defense Communications Agency for the successful development of heterogeneous network TCP / IP protocol, the United States to the agreement of California at Berkeley as part of BSD UNIX, so the agreement has been popular in the community, thus the birth of the real Internet. In 1986, the U.S. National Science Foundation (National Science Foundation, NSF) developed by ARPAnet TCP / IP communication protocol, research and education services in the five supercomputer centers NSFnet established on the basis of wide-area network. Because the United States National Science Foundation to encourage and sponsor, many universities, government-funded research institutions and even private research institutions have put themselves in the local area network into NSFnet. At that time, ARPAnet had been out of the military part of the home network, build their own network - Milnet. ARPAnet - the father of the network, gradually being replaced by NSFnet. By 1990, ARPAnet has withdrawn from the stage of history. Today, NSFnet Internet has become one of the important backbone. In 1989, developed by the CERN WWW, the Internet to achieve wide-area hypermedia information interception / retrieval basis. In the 90 years ago, Internet use has been limited to research and academic fields. Commercial institutions into the Internet has been subject to regulation or this or that plagued the traditional problems. In fact, such as the United States National Science Foundation has funded the construction of Internet on the Internet, government agencies are not interested in commercial activities. In 1991, the United States, three companies were operating their own CERFnet, PSInet and Alternet network, to a certain extent, to provide Internet network services. They formed a "Commercial Internet Society" (CIEA), announced that users can place their Internet subnet used for any commercial purpose. Commercial Internet service providers have enabled businesses can finally stand up to enter the Internet. Internet businesses into a strange world that it found in the communications, information retrieval, customer service, great potential. Thus, the potential out of control. Around the world numerous companies and individuals have entered the Internet, bring Internet history of the development of a new leap forward. Internet is now linked with more than 160 countries and regions, more than 40,000 subnets, hosts more than 500 million computers directly over 40 million users, becoming the world's most extensive information resources on the public computer network. Internet is considered the prototype of the future global information highway. 【】 To achieve the four elements of the network 1, communications lines and communications equipment 2, a separate computer functions 3, network software, software support 4, data communication and resource sharing 【】 History of the development of computer network With the 1946 world's first electronic computer than a decade after the advent of time, because the price is very expensive, very few computers. Early so-called computer network is mainly to resolve this contradiction arising in the form of a single computer through Tongxin line with the number of terminals directly connected, we can also see this approach as the most simple LAN shape. The first network, by the U.S. Defense Advanced Research Projects Agency (ARPA) to establish. Many of the concepts of modern computer networks and methods, such as packet switching technologies are from the ARPAnet. ARPAnet was not only leased line packet-switched interconnect technology, and made a wireless, packet-switched satellite network technology - the result of the TCP / IP come out. Stage of development of computer network The first generation: a remote terminal connection The early 20th century, 60 Terminal-oriented computer network: the host is a network of centers and controllers, terminals (keyboard and monitor) and distributed throughout the host is connected, the user terminal through a local host using the remote. Provides only communication between the terminal and the host, can not communicate between subnets. The second generation: computer network stage (LAN) The mid-20th century, 60 Multiple host connectivity, to achieve communication between the computer and the computer. Include: communication subnet, the user resource subnet. End users can access the local host and all hosts subnet communications hardware and software resources. Circuit switching and packet switching. Third Generation: computer networking stage (wide area network, Internet) 1981 International Organization for Standardization (ISO) developed: Open System Interconnection Basic Reference Model (OSI / RM), to achieve between different manufacturers of computers interconnected. TCP / IP protocol was born. The fourth generation: the information highway (high-speed, multi-service, large data) Broadband Integrated Services Digital Network: Information Highway ATM technology, ISDN, Gigabit Ethernet Interactive: online TV on-demand, videoconferencing, video telephony, online shopping, online banking, high-speed network library, visualization. The history of network development in China 1, Internet Development in Different Stages The development of the INTERNET to 1987 by the Chinese Academic Network CANET first letter to the world E-mail to sign. After several years of development, the formation of the four major network systems, namely: Chinese Academy of Science and Technology Network CSTNET; the Ministry of Education Education and Research Network CERNET; the former Ministry of Posts and Telecommunications and the former Ministry of Electronics CHINANET the Golden Bridge Network CHINAGBN. Internet Development in China can be roughly divided into three stages: The first phase 1987-1993, and also research and test phase. During this period some of China's scientific research departments and institutions of higher learning began to study InternetInternet technology, and carried out research projects and scientific and technological cooperation, but at this stage of the network application is limited to a small range of e-mail service. The second stage is from 1994 to 1996, the same initial stage. April 1994, Zhongguancun area network engineering education and research and demonstration into the Internet, an official from China was internationally recognized as a national Internet. After, Chinanet, CERnet, CSTnet, Chinagbnet and other Internet networks have launched a nationwide project, Internet began to enter public life, and in China have been developing rapidly. To the end of 1996, the number of Chinese Internet users reached 20 million, the use of Internet services and applications carried out by gradually increasing. The third stage, from 1997 to the present, is the fastest Internet in the stage of fast. The number of domestic Internet users remained 97 years later the growth rate of doubling every six months. Growth to today, has more than 10 million Internet users. According to the China Internet Network Information Center (CNNIC) released a statistical report, as of June 30, 2003, the total number of Internet users in China is 6800 million. Beginning of the year this figure increased by 890 million, compared with the same period in 2002 increased by 2220 million. China currently has five lines of furniture have independent international import and export of commercial backbone of the Internet unit, there are for education, science and technology, trade and other areas of non-profit Internet backbone units. There are more than 600 Internet access service provider (ISP), of which there are 140 inter-provincial business. With improvements in network infrastructure, user access aspects of new technologies, eight-way access and carrier services to the diversification of capacity, slow rate of formation of the access network bottleneck will be further improved, Internet speed will be faster to promote the realization of more applications on the Internet. 【Category】 Network Press coverage points: Local area network LAN (typically a few meters scope to tens of kilometers) MAN MAN (boundary between the WAN and LAN) Wide area network WAN (typically tens of scope to several thousand km) Topology by Category: BUS Ring Star Mesh By way of exchange of information points: Circuit switching Message switching Packet switching Classification of cable networks by fiber optic transmission medium wireless LAN network is usually a single transmission medium, and metropolitan and wide area networks using a variety of transmission media. Classification by means of communication point to point transmission network broadcast transmission network The purpose of classification by the network to share resources with network data processing network data transmission network with the purpose of the current network is not unique. Way classification by service client / server network peer
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The use of the network
】 【Network Transmission Deputy Director of Modern Chinese Poetry Lan Media Commission that the network communication has three basic characteristics: global, interactive, way of hypertext links. Therefore, its transmission to the network is defined as: the background of the global mass of information to participants massive object, the participants also receive and publisher of information and provide feedback of information at any time, formation and reading the text it is casual link between the various texts, and the formation of the cultural meanings of the different degree of hypertext in the completed ("the international press," 2000 No. 6 p. 49). Some people believe that "Internet Communication" has been widely seen in the communication of a new term. It is a relative of three media that newspapers, radio and television purposes. Network communication refers to the multimedia, networking, digital technology as the core of the Internet, also known as network communication is a product of the modern information revolution ("the international press," No. 6 2000, p. 49). We believe that in fact refers to the so-called network communication through computer networks of the human information (including news, knowledge and other information) dissemination activities. Dissemination of the information in the network, stored in digital form in the optical and magnetic storage media, high-speed communication through computer networks, and through the use of computer or similar device to read. Network communication to the computer communications network, based on the information transmission, exchange and use of communication to achieve their social and cultural purposes. Huge readership network communication, high-speed communication via the Internet. Network Communication related subjects are: communication, political science, sociology, psychology, journalism, economics, computer science. 【Telephone】 Network Internet telephony, also known as IP telephony, it is through the Internet Protocol (Internet Protocol, IP) for voice transmission. The traditional way of international calls is to transmit the analog voice signal is first converted to, the sound transmitted through the copper to each other. VoIP voice sucked through a gateway (gateway) is converted to data signals, and is compressed into data packets (packet), then sent out from the Internet, the receiver receives the data packet, the gateway will extract it, sound re-converted to the other to listen. In general the current Internet phone-line can be divided into 3: PC to PC, PC to Phone, Phone to Phone. Internet phones using TCP / IP protocol, by special software into the caller's voice into digital signals (often re-compressed, which is good and bad Internet phone software, key technical points), and then packaged to form a small data packet, a small Free search for network packet free space, the voice data to each other, each other's specialized equipment or software that receives data packets for a voice speaking in front of data packets into the anti-process, if inconsistent with the other receivers, but also To make the technical processing to enable the voice to be restored. Call the whole, we do not specifically dedicated leased lines, but rather they must attack to use the network, saving call costs. General costs a few cents in the domestic and international fees are generally a few cents, the cost is very low. Internet telephony is a revolutionary product, it can be done through the Internet in real-time transmission and bilateral dialogue. You can through local Internet service provider (ISP) or telephone company to a very low cost calls to other phone users around the world, the network is free to call the internal phone. From office workers to home users, students, Internet surfers, gamers and grandparents, who, VoIP provides a completely new, easy, economical way to and around the world, friends and colleagues call. Hard】 【Network "Network disk" is a dedicated storage space, users visit a web site the way, can easily upload, download files, and unique to share, grouping with more than a traditional storage concept. Compared with other similar products, "network drive" products with an intuitive preview, four sharing, group management, security and stability of the four characteristics. Network hard disk is "a network connection for remote management and use of hard disk space", can be used for transmission, storage and backup computer data files, user and management. Site users can have Internet access anywhere in the world of computer terminals, the connection to use "e Netcom" network hard drive to provide services. 【Education】 Network Online education refers to the network environment, with modern educational thinking and learning philosophy as a guide, give full play to the network features and rich variety of educational resources online education, educators and learners to provide a network of teaching and learning service, the service is reflected in the delivery of content with digital technology. Carried out by non-face learner-centered education. Financial】 【Network The so-called network of financial, also known as e-finance (e-finance), refers to the Internet (Internet) on the implementation of financial activities, including the network of financial institutions, online financial transactions, networks, and network financial supervision of financial markets and so on. It is different from the traditional to the physical form of existence of financial activity, is present in the financial activities in the electronic space, whose existence is a form of virtualization, the operating mode is networked. It is information technology, especially the product of the rapid development of Internet technology, is to adapt to electronic commerce (e-commerce) development needs arising from the financial operation mode of the Internet age. 【TV】 Network Internet TV, also known as IPTV (InteractivePersonalityTV), it will television _set_s, personal computers and handheld devices as a display terminal, through the _set_-top box or computer access to broadband networks, digital television, time-shifted TV, interactive TV and other services, the emergence of Internet TV It brings a whole new way of TV viewing, it changed the previous mode of passive TV viewing to realize the television on-demand viewing, with the look with the stop. 【Insurance】 Network Insurance is an emerging network of computer networks as a medium of insurance marketing model, are different from traditional insurance agent marketing. Emergence and development of network insurance is a historical trend, it represents the direction of the international insurance industry. At present, the insurance web site can be divided into two categories: The first is the insurance company self-built website, mainly to promote their own insurance, such as the Ping An Insurance's "PA18", Taikang Life Insurance's "Tai-line" and so on; second is an independent third-party insurance Web site by the professional Internet service provider (ISP) funded the establishment of the insurance site does not belong to any insurance company, but also provide insurance services, such as easy security, network insurance. Obviously, these two sites represent the largest category of China's Internet development level of insurance, when the implementation of their strategy and market approach to rational, objective research and analysis, will be able to grasp the profound development of China's Internet insurance. Network insurance is a huge social systems engineering, related to banking, telecommunications and other industries, this project takes a long time to complete. Hackers attack computer network systems that currently lack their own security protection, Internet Insurance insecurity risks; and the network between the parties to the insurance because the insurance and the profound complexity of human factors background and interests, making the online complaints, claims likely to breed fraud. Therefore, the operation is difficult to rely solely on online support network insurance. How to prohibit and punish the use of network behavior of the insurance for insurance fraud? How to implement online underwriting and claims and payment online? Internet Insurance in China is still a long way to go. Internet Insurance technology research by the National Science and Technology R & D personnel package of "security reinforcement system," the security of the server maintenance, resistance to hackers, viruses and worms invasion. Deadline December 7, 2007, the Central News Network to broadcast a new generation of "security reinforcement system" has been put into operation. 】 【Network Marketing Internet Marketing (On-lineMarketing or Cybermarketing) the full name of the network of direct marketing, direct marketing is a form of corporate marketing practices and modern information and communication technology, computer network technology product of the combination, refers to electronic information technology companies based on a computer network as a medium and means to conduct various marketing activities (including online research, web promotion, network development of new products, network marketing, network distribution, network services, etc.) in general. Network marketing are the exact steps are: First, build a platform for large enterprise network marketing companies can build their own websites, small companies to the alliance with the network, the Internet security of a "home." Second, web promotion (search engine optimization, business publishing, e-mail, blog marketing, ... ...) Third, the establishment of the consumer database. Consumers are strategic as_set_s of enterprises, enterprises must pay attention to using the network to collect, analyze consumer information, such as the registered user information, user feedback, comments, suggestions, build and manage consumer database, identify the individual needs of consumers, of consumption those of consumer behavior, habits, establish and develop long-term personal relationship customers. Lock online consumers. The one hand, the proliferation of information on the Internet, on the other hand the limited time consumers, enterprises must begin to attract consumers to the Internet and encourage them to visit companies and long visits to the site marketing strategy. Fourth, emphasis on personalization. In order to win consumers rely on, companies must be independent of each consumer as a different individual. New guidelines for consumers to shop today is: "I asked either to provide products, or I do not!" The company's answer can only be: "to do according to their demands, otherwise not bother them" Fifth, attention to differentiated marketing, direct marketing. Differences in use of the Internet for marketing, vigorously carried out, including E-mail marketing, including direct marketing. Sixth, a rapid customer response mechanism. Including customer comments and suggestions, complaints and grievances of the rapid response, and rapid logistics system. To maximize the advantage of every opportunity to communicate with customers, as quickly as possible to provide time to meet customer specific requirements and delivery of services.
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Internet Language
Network on behalf of a certain language of the Internet culture, it is widely appear in the chat, forums (BBS) and other Internet applications, and penetrate into the real life, our lives had an impact. Its wide variety of sources, many drawn from the colloquial dialect, the foreign language, abbreviations, harmonics, etc., are mixed languages. Before the Opium War, the whole of China Europa few people will know, What is the meaning of the English, did not know Mauser, brandy what it is. However, the Opium War, these words quickly enter into the Chinese language, and long preserved by transliteration. This example can be seen that the emergence of Internet language, giving more life and vitality of the language.
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The origin of online games
Business model: the rapid expansion of the online game market to stimulate the development of network services, network access fees start of the game times, many consumers are willing to pay high fees to play online games. From "Kaisi Mai Island" $ 12 per hour to $ 6 per hour GEnie, the second generation of online games is the main billing by the hour, although there have been a special case of monthly billing, but failed to form climate. 1978, University of Essex in the UK, Reuter Rub Shaw prepared with DEC-10 game of the world's first MUD - "MUD1", which is more than a plain text world, with 20 interconnected rooms and 10 instructions, the user can log in the database interaction, or through exchanges with other players chat system. Trudeau Buxiao after leaving the University of Essex, to maintain MUD1 transferred to the work of Richard Battle, Battle MUD developed by Trudeau Buxiao special language - "MUDDL" continue to improve the game, he the number of rooms to 400, and further improve the database and chat system, an increase of more tasks, and every player produced a scoring process. MUD1 is the first truly interactive, real-time multiplayer online game, it can guarantee the sustainable development of the virtual world. Although the system will reboot several times a day, but the scenes in the game after the restart, monsters and puzzles remain unchanged, making the role players to achieve sustained development. MUD1 Another important feature is that it can be any one in the world PDP-10 running on the computer is not limited to the internal system of the University of Essex. In 1985, Bierluodeng persuade General Electric Company (GE) of the information services sector to invest in a similar CompuServe, and commercial, ASCII text-based Web services platform, this platform is called GEnie (GE Network for Information Exchange). GEnie was officially launched in October, its low fees in a big hit among users, which is also a strong sense of superiority of CompuServe has felt the pressure of competition. GEnie system actually is the use of GE Information Services server idle time in the night to provide users with services, so fees are very low, at the price of 6 dollars per hour, almost half of CompuServe.
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Network - the backbone of China's four
China Public Computer Internet (CHINANET) Ministry of Posts and Telecommunications, also known as the Internet, the Chinese public Internet network, the Ministry of Post and Telecommunications and Internet-based network management technology, electronic information network, connectivity with the Internet in early 1995, and in May to provide services to the community. CHINANET backbone network from the access network composed of backbone networks is the main information channel, from cities and municipalities and provinces will constitute a network node; access network in the provinces (regions) to build a network of network contacts. CHINANET flexible access methods and cities across the country access point, you can easily access the international Internet, access to Internet resources and the wealth of information on a variety of services, and for the domestic computer interconnection, sharing of information resources for domestic provide a convenient network environment. China Education and Research Network (CERNET) Launched in 1994, completed the first phase of the end of 1995, including Beijing (Network Center), Shanghai, Nanjing, Guangzhou, Wuhan, Xi'an, Chengdu and Shenyang higher concentration of large cities. America's international line is connected. National Backbone Network (a total of 11 64Kbps DDN line) opened in October 1995. Phase II is completed, the national backbone and international networking escalation to 2Kbps more backbone, international networking to achieve 8Kbps above. China Science and Technology Network (CSTNET) Presided over by the Chinese Academy of Sciences, the United Tsinghua University, Beijing to jointly build. Opened in April 1994 and Internet leased line connection. May 21, 1994 completed a master of the highest CN domain name server _set_tings, to achieve with the Internet's TCP / IP connection. Basically completed the end of 1995, "one hundred network" project. The end of 1997, has more than 100 Ethernet connections, more than 3,000 computers, more than 1 million users, a wide area of China, use large, performance, communication capacity, service facilities of the national research and education network. China Golden Bridge Information Network (CHINAGBN) The national public economic information network, the former Ministry of Electronics Industry Management, for the government, enterprises, institutions and the public to provide data communications and information services. Golden Bridge Network and Internet connectivity by the end, has opened 24 cities, the development of more than 1,000 local and remote terminal emulation to provide comprehensive Internet services.
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Internet Basics
1. What is a Local Area Network Local area network (local area network) is often referred to as "LAN", abbreviated as LAN. LAN is the least complex computer network. LAN is only by the network on the same site a group of computers linked together. LAN usually get very close, it is one of the most widely used class of networks. Usually has the following characteristics of network known as the LAN. 1) The geographical area covered by the network is relatively small. Usually no more than several tens of kilometers, even only in a building or a room. 2) information transfer rate is relatively high, ranging from 1Mbps to 10Mbps, has recently been reached 100Mbps. The run-time wide area network transmission rate is usually 2400bps, 9600bps or 38.4kbps, 56.64kbps. Dedicated line only to 1.544Mbps. 3) Network operation and management rights belong to a unit. 2. What is a Wide Area Network WAN (wide area network, WAN) which is of a wide range of complex network systems. LAN WAN constituted by two or more of these to pass through the LAN connection between the distance of more than 30mile *. WAN can be a large number of continents composed of LAN and MAN. WA N is the most well-known Internet, which consists of thousands of LAN and WAN global composition. Sometimes LAN, MAN and WAN boundary between the very obvious, it is difficult to determine where the termination of LAN, MAN or WAN where to start. However, the four network characteristics can be - the communication medium, protocol, topology and the interconnection of private networks and public network boundary points to determine the type. Communication medium is used to connect computer and network cables, fiber optic cables, radio waves or microwaves. LAN is usually the end of the communication medium to change places, such as changing from cable-based fiber-optic wires. LAN is usually through the wire and cable and other fiber-optic cable LAN connection. 3. What is a bridge 4. What is a gateway Gateway can not be fully classified as a network hardware. With the general terms, they should be able to connect different network combination of hardware and software products. In particular, they can use a different format, communication protocol or structure connects the two systems. And not the same as discussed earlier in this chapter, re-packaging of information through the gateway is actually so that they can be read another system. To accomplish this task, the gateway must be able to run on several layer OSI model. Gateway must communicate with the application, session establishment and management of the transmission has been encoded data, and parsing the logical and physical address data. Gateway can be located in the server, or mainframe computer. As the gateway with powerful features and applications, and most of the time related to the price they are more expensive than some of the router. In addition, because more complex transmission gateway, which transfers data at a rate lower than bridges or routers. It is slow because the gateway, which may be causing network congestion. However, in some cases, only the gateway can do the job. Career in your network, you're likely to hear in the e-mail system environment discussion on the gateway. Common gateway, including e-mail gateway, described as follows: - E-mail gateway: the gateway through which one type of system from another type of system to transmit data. For example, e-mail using the Eudora e-mail gateway can allow people with the use of GroupWise e-mail people communicate with each other. - IBM Host Gateway: Through this gateway, can be a personal computer and the IBM mainframe communication between the establishment and management. - Internet Gateway: The gateway to allow and manage access between LAN and the Internet. LAN Internet Gateway can restrict certain users to access the Internet. And vice versa. - LAN Gateway: Through this gateway, running different protocols or operating at different layers on the OSI model between LAN segments can communicate with each other. Router, even with only one server can act as a LAN gateway. LAN Gateway also includes a remote access server. It allows remote users to access the LAN via dial-up. 5. Network type Require each network cabling, network equipment, file servers, workstations, software and training, these elements in many different ways can create a comprehensive needs and resources of specific units to adapt the network. Some networks start-up costs low, but high costs of maintenance and upgrades; while others are more costly when the network, though based, but easy to maintain, upgrade path easy. Distinguish between the type of network is very clear that the network topology. Topology refers to the physical layout of the network and its logical characteristics. Like a description of the physical layout of the office, building or campus wiring diagram of how, often referred to as the cable lines. The logic is the network signal along the cable from one point to another point transmission method. Network layout can be spread out, all the cable stations in the network roll out; or can be centralized, each station with the distribution of packets between the workstation has a physical connection to the central equipment. Focus on the layout of such stars, the stars of the point of the workstation; scattered pattern a bit like a team of climbers, each of the mountain climbers in a different location, but by a long rope connected. Logic topology, including packet transmission path in the network. There are three main topologies: bus topology, ring topology and star topology. The purpose of a unit need to _select_ the network type according to the work, while the topology of the network must match the type _select_ed. For example, some companies use the network level is higher than other companies. Software applications used by the company the type and amount of the transmission frequency and the number of packets, that is, we often say that the network traffic (network traffic). If the main access to word processing software, network users, then the network traffic is comparatively low, most of the work and not in the workstation on the network. Client / server architecture, application software according to its design, will produce moderate to high network traffic. If the network to regularly exchange such as Microsoft SQL Server or Oracle database files and other database information, it will produce moderate to high network traffic. As for the science program and web publishing, since the data file is huge, so the information flow is very high. Also, graphics-intensive applications such as changing graphics and desktop multimedia online meeting will have a high network traffic. Host and the server on the network and use the influence of the type of software applications are closely related. For example, if you frequently access the database server to generate financial statements and sales charts, then it certainly caused by network traffic than the occasional access to business communications or correspondence that contains the template file server is much higher. When you need to determine what kind of topology, it should consider whether there are other networks and the network connection. Computer no more than 4 small business company with a network topology through the WA N certainly other sites connected with the needs of industrial plant topological structure is different. In addition to small companies connected with the outside of the Internet, but perhaps not with the other network connection. The industrial plant will contain multiple interconnected networks, which may have controlled a network of factory machinery, for commercial system network, a network for research and extension to other sites connected to the WAN. Some network topologies will provide better performance than any other network topology connectivity. High-traffic network requires high-speed data transmission capabilities. Greatly affect the speed of the network user productivity, high-speed WAN for the transmission over long distances or images, graphics and other large files is especially important. Protection of data can only be accessed by authorized users, that is, security issues, that affect another important aspect of network design. Use of network devices secure network, password, control software and other technology to restrict access to information and resources, but also often use encryption, encryption of packets and only allows authorized to decrypt the computer. Safe use of fiber optic cable network, making the data to unauthorized users to minimize the risk of interception. Another security measure is to network devices and servers on the restricted sites, such as computer rooms and wiring clo_set_s. Network topology directly affects the potential development of the network. Install the network, perhaps you want to add more users, these users may at the same office, and possibly in other offices, or in other floors. And most likely for long-distance access to information, the need to LAN and WAN connectivity. 6. Network protocol A LAN can be formed by a series of subnets, and a WAN, such as Internet, can be formed by a series of self-government network. You can only use the Ethernet LAN, and WAN but may include Ethernet, Token Ring, X.25, and other networks. Through the Internet Protocol (IP), a packet can be sent to the LAN and WAN different subnets on different networks, the only condition is that these networks are used to ensure that the transfer option and TCP / IP compatible, these options include: - Ethernet. - Token Ring network. - X.25. - FDDI. - ISDN. - Frame Relay. - (With conversion) AT M. - Network transport header (eg, Ethernet) The basic function is to provide IP data transmission, packet addressing, packet routing, packet segmentation and a simple error detection. Through the IP addressing conventions, you can successfully transfer the data and routing to the correct network or subnet. Each network node has a 32-bit IP address, it and 48-bit MAC address of working together to complete the network traffic. The address not only identifies a given network, but also indicates which of the nodes on the network 7.TCP/IP Agreement TCP / IP protocol (Transfer Control Protocol / Internet Protocol) is called Transmission Control / Internet Protocol, also known as network communication protocol, which includes hundreds of features of the agreement, such as: remote login, file transfer and e-mail, and TCP protocol and IP protocol is to ensure the integrity of data transmission are two basic key agreement. Generally speaking TCP / IP is the Internet protocol suite, not just TCP and IP. TCP / IP protocol is the basic transmission unit of data packets (datagram). TCP protocol is responsible for the data divided into packets and each packet with a header; IP protocol header on top of each receiver host address, so that the data to find their own place to go. If data loss during transmission, data distortion, etc., TCP protocol will automatically require the data re-transmission, and re-group package. In short, IP protocol to ensure data transmission, TCP protocol to ensure data transmission quality. TCP / IP protocol data transmission based on TCP / IP protocol of the four structures: the application layer, transport layer, network layer, interface layer, the data transmission through a layer of each will add a header in the data, including data for layer protocols use the same receiver, and at the receiving end, each used by header should remove the layer, so to ensure consistent data transmission format. 8.IP Address 1) IP address of the basic concepts Internet rely on TCP / IP protocol, on a global scale to achieve different hardware, different operating systems, different networks to interconnect. In the Internet, each node relies on a unique IP address distinguishable from one another and each other. IP address is a 32-bit binary number of the address, the four 8-bit fields, each field is separated with dots between, used to identify TCP / IP host. Each IP address contains two parts: the network ID and host ID. Network ID identifies a physical network in the same places on all hosts, the host ID identifies the physical network each host, so every computer on the Internet rely on its own unique IP address to identify it. IP address form the basis of the Internet, it is so important, every right to _set_ their own networked computers IP address, there is a unified body-IANA is responsible for the applicant organization is assigned a unique network ID, and the organization can be their own network, each host is assigned a unique host ID, as a unit has no right to decide their own city's streets in their name and house number, but you can decide on all the units within the same office number. 2) static IP and dynamic IP IP address is a 32-bit binary number of the address, in theory, there are about 40 billion (2 of 32 power) possible address combinations, this seems like a lot of address space. In fact, according to the network ID and host ID bits of different rules, IP addresses can be divided into A (7-bit network ID and 24-bit host ID), B (14-bit network ID and 16-bit host ID), C (21 8-bit network ID and host ID) three, due to historical reasons and differences in technological development, A Class B Class address and the address allocation is almost exhausted, the current can be allocated for organizations around the world, only C class address. So the IP address is a very important network resources. 8. What is a router Multi-port router is a device that can connect different transmission rates and run on a variety of LAN and WAN environments, you can use different protocols. Routers are OS I model the third layer. Guide the network layer segment from one segment to another data transmission, but also can guide the network from one network to another data transmission. In the past, because too much attention to the third level or higher level of data, such as the protocol or logical address, router, switches and bridges than ever slow. Therefore, unlike the bridge and the second layer of switches, routers, is dependent on the agreement. Forward with some kind of agreement in their data before they have to be designed or configured to recognize the agreement. The traditional stand-alone LAN routers are slowly being supported routing switches replaced by the third layer. However, the concept of the router is still very important. Stand-alone router is still using the wide area network technology to connect remote users a choice. osi network International Organization for Standardization (ISO) proposed a reference model OSI seven-layer model: 7 Application Layer 6 Presentation Layer 5 Session Layer 4 Transport Layer 3 Network Layer 2 Data Link Layer 1 Physical Layer 9. What is a switch Switch (switch) in the communication system is a complete exchange of information enabled devices. Recognition is based on MAC address, forwarding packets to complete the package function network devices. The switch can "learn" MAC address and its stored in the internal address table, the data frame by the intended recipient origin and the exchange between the temporary path to the data frame directly from the source address to a destination. Broadly speaking, the network switch is divided into two categories: wide-area network switches and LAN switches. WAN switches, mainly used in the field of telecommunications, providing the basic platform for communication. The local area network LAN switches are used for connecting devices such as PC, and network printers.
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Encyclopedia
wangluo Network network Connected by a number of components of a system. Electrical components can be components, mechanical components, optical components or other components. By the electronic components, vacuum electronic devices or other solid-state electronic devices connected into the electrical network, also known as circuits. Since the 60s, people connected by a number of stand-alone system, even by many non-electric facilities, non-electrical connection system, also known as network. The former, such as communication networks, computer networks, transmission power distribution network; the latter, such as irrigation networks, transportation networks. (Lu Zhigang)
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English Expression
: network
n.: lattice, net, nexus, solenoid, an inverse network, enlist the services of, (computer, telecom, etc.) network
internet