Будущее интернета

Несколько технических вызовов{претензий} должны быть преодолены, если Интернет должен продолжить расти с текущей феноменальной скоростью. Первичный вызов{претензия} должен создать достаточную вместимость{способность} приспособить{разместить} увеличения движения. Интернет-движение увеличивается, поскольку больше людей становится интернет-пользователями, и существующие пользователи посылают когда-либо большие количества данных. Если объем{том} движения увеличится быстрее чем вместимость{способность} увеличений сети, то скопление произойдет{встретится}, подобное скоплению, которое происходит{встречается}, когда слишком много автомобилей пытаются использовать шоссе. Чтобы избегать скопления, исследователи развили технологии, типа Плотного Разделения Волны, Мультиплексирующего (DWDM), которые передают{перемещают} больше битов{частиц} в секунду поперек оптического волокна. Скорость маршрутизаторов и другого погрузочно-разгрузочного оборудования пакета должна также увеличиться, чтобы приспособить{разместить} рост. В ближайшей перспективе, исследователи развивают более быстрые электронные процессоры; в долгосрочной перспективе, новые технологии требуются.

Другой вызов{претензия} вовлекает IP адреса. Хотя оригинальный{первоначальный} проект протокола обеспечил адреса для 4.29 миллиардов индивидуальных компьютеров, адреса начали заканчиваться, потому что они были назначены в блоках. Исследователи развивали технологии, типа Перевода Адреса Сети (ТУЗЕМНОГО), чтобы сохранить адреса. ТУЗЕМНЫЙ позволяет многократные компьютеры в месте жительства "разделять" единственный{отдельный} интернет-адрес. Инженеры также планировали следующего поколения из IP, названного IPv6, который будет обращаться с еще многими адресами чем текущая версия.

Короткий, названия{имена} области "легкий помнить" находятся также в короткой поставке. Много названий{имен} области, которые используют простой формат http://www. [слово] .com, где [слово] - имя нарицательное или глагол, находится уже в использовании. В настоящее время, только несколько окончаний позволяются, типа .com, .org, и .net. В ближайшем будущем, дополнительные окончания будут позволяться, типа .biz и .info. Это очень расширит число{номер} возможных URL.

Другие важные вопросы относительно интернет-роста касаются правительственных средств управления, особенно налогообложение и цензура. Поскольку Интернет рос так быстро, правительства имели немного времени, чтобы передать законы, которые управляют его развертыванием и использованием, налагают налоги на интернет-торговлю, или иначе регулируют содержание. Много интернет-пользователей в законах цензуры представления{вида} Соединенных Штатов как нарушение на их конституционном праве на свободу слова. В 1996 Конгресс Соединенных Штатов передал закон о Благопристойности Коммуникаций, который сделал преступлением, чтобы передать неприличный материал по Интернету. Акт привел к непосредственному{немедленному} протесту от пользователей, экспертов промышленности, и групп гражданских свобод, противоположных такая цензура. В 1997 Верховный Суд Соединенных Штатов объявлял неконституционный акт, потому что это нарушило Первые права Поправки на свободу слова. Законодатели ответили в 1998, передавая более узкий антипорнографический счет{законопроект}, Ребенок закону о Защите Онлайн (COPA). COPA требовал, чтобы коммерческие Вебсайты гарантировали, что дети не могли получить доступ к материалу, который считают вредным для младших. В 1999 федеральный судья блокировал COPA также, управление{постановление}, что это опасно ограничит конституционно защищенную свободу слова.

Увеличение коммерческого использования Интернета усилило проблемы{дела} секретности и безопасность. С кредитом или дебетовой картой, интернет-пользователь может заказать почти что - нибудь от интернет-участка{сайта} и поставить это их дому или офису. Компании, занимающиеся коммерцией по интернет-потребности, которую сложная{искушенная} безопасность измеряет, чтобы защитить кредитную карточку, счет в банке, и числа{номера} социального обеспечения от неправомочного доступа, поскольку они проходят поперек Интернета. Любая организация, которая соединяет{подключает} ее интранет с глобальным Интернетом, должна тщательно управлять пунктом{точкой} доступа, чтобы гарантировать, что посторонние не могут разрушить{прервать} внутренние сети организации или получить неправомочный доступ к компьютерным системам организации и данным. Вопросы правительственного контроля{управления} и интернет-безопасности продолжат быть важными, поскольку Интернет растет.

English

Internet

INTRODUCTION

Internet, computer-based global information system. The Internet is composed of many interconnected computer networks. Each network may link tens, hundreds, or even thousands of computers, enabling them to share information with one another and to share computational resources such as powerful supercomputers and databases of information. The Internet has made it possible for people all over the world to effectively and inexpensively communicate with one another. Unlike traditional broadcasting media, such as radio and television, the Internet does not have a centralized distribution system. Instead, an individual who has Internet access can communicate directly with anyone else on the Internet, make information available to others, find information provided by others, or sell products with a minimum overhead cost.

The Internet has brought new opportunities to government, business, and education. Governments use the Internet for internal communication, distribution of information, and automated tax processing. In addition to offering goods and services online to customers, businesses use the Internet to interact with other businesses. Many individuals use the Internet for shopping, paying bills, and online banking. Educational institutions use the Internet for research and to deliver courses to students at remote sites.

The Internet’s success arises from its flexibility. Instead of restricting component networks to a particular manufacturer or particular type, Internet technology allows interconnection of any kind of computer network. No network is too large or too small, too fast or too slow to be interconnected. Thus, the Internet includes inexpensive networks that can only connect a few computers within a single room as well as expensive networks that can span a continent and connect thousands of computers. See Local Area Network.

Internet service providers (ISPs) provide Internet access to customers for a monthly fee. A customer who subscribes to an ISP’s service uses the ISP’s network to access the Internet. Because ISPs offer their services to the general public, the networks they operate are known as public access networks. In the United States, as in many countries, ISPs are private companies; in countries where telephone service is a government-regulated monopoly, the government often controls ISPs.

An organization that has many computers usually owns and operates a private network, called an intranet, that connects all the computers within the organization. To provide Internet service, the organization connects its intranet to the Internet. Unlike public access networks, intranets are restricted to provide security. Only authorized computers at the organization can connect to the intranet, and the organization restricts communication between the intranet and the global Internet. The restrictions allow computers inside the organization to exchange information but keep the information confidential and protected from outsiders.

The Internet has grown tremendously since its inception, doubling in size every 9 to 14 months. In 1981 only 213 computers were connected to the Internet. By 2000 the number had grown to more than 100 million. The current number of people who use the Internet can only be estimated. One survey found that there were 61 million Internet users worldwide at the end of 1996, 148 million at the end of 1998, and 407 million by the end of 2000. Some analysts estimate that the number of users will double again by the end of 2002.

USES OF THE INTERNET

From its inception in the 1970s until the late 1980s the Internet was a U.S. government-funded communication and research tool restricted almost exclusively to academic and military uses. As government restrictions were lifted in the early 1990s, the Internet became commercial. In 1995 the World Wide Web (WWW) replaced file transfer as the application used for most Internet traffic. The difference between the Internet and the Web is similar to the distinction between a highway system and a package delivery service that uses the highways to move cargo from one city to another: The Internet is the highway system over which Web traffic and traffic from other applications move. The Web consists of programs running on many computers that allow a user to find and display multimedia documents (documents that contain a combination of text, photographs, graphics, audio, and video). Many analysts attribute the explosion in use and popularity of the Internet to the visual nature of Web documents. By the end of 2000, Web traffic dominated the Internet—more than 80 percent of all traffic on the Internet came from the Web.

Companies, individuals, and institutions use the Internet in many ways. Companies use the Internet for electronic commerce, also called e-commerce, including advertising, selling, buying, distributing products, and providing customer service. In addition, companies use the Internet for business-to-business transactions, such as exchanging financial information and accessing complex databases. Businesses and institutions use the Internet for voice and video conferencing and other forms of communication that enable people to telecommute (work away from the office using a computer). The use of electronic mail (e-mail) speeds communication between companies, among coworkers, and among other individuals. Media and entertainment companies use the Internet for online news and weather services and to broadcast audio and video, including live radio and television programs. Online chat allows people to carry on discussions using written text. Scientists and scholars use the Internet to communicate with colleagues, perform research, distribute lecture notes and course materials to students, and publish papers and articles. Individuals use the Internet for communication, entertainment, finding information, and buying and selling goods and services.

HOW THE INTERNET WORKS

Internet Access

The term Internet access refers to the communication between a residence or a business and an ISP that connects to the Internet. Access falls into two broad categories: dedicated and dial-up. With dedicated access, a subscriber’s computer remains directly connected to the Internet at all times by a permanent, physical connection. Most large businesses have high-capacity dedicated connections; small businesses or individuals who desire dedicated access choose technologies such as digital subscriber line (DSL) or cable modems, which both use existing wiring to lower cost. A DSL sends data across the same wires that telephone service uses, and cable modems use the same wiring that cable television uses. In each case, the electronic devices that are used to send data over the wires employ separate frequencies or channels that do not interfere with other signals on the wires. Thus, a DSL Internet connection can send data over a pair of wires at the same time the wires are being used for a telephone call, and cable modems can send data over a cable at the same time the cable is being used to receive television signals. The user usually pays a fixed monthly fee for a dedicated connection. In exchange, the company providing the connection agrees to relay data between the user’s computer and the Internet.

Dial-up is the least expensive access technology, but it is also the least convenient. To use dial-up access, a subscriber must have a telephone modem, a device that connects a computer to the telephone system and is capable of converting data into sounds and sounds back into data. The user’s ISP provides software that controls the modem. To access the Internet, the user opens the software application, which causes the dial-up modem to place a toll-free telephone call to the ISP. A modem at the ISP answers the call, and the two modems use audible tones to send data in both directions. When one of the modems is given data to send, the modem converts the data from the digital values used by computers—numbers stored as a sequence of 1s and 0s—into tones. The receiving side converts the tones back into digital values. Unlike dedicated access technologies, a dial-up modem does not use separate frequencies, so the telephone line cannot be used for regular telephone calls at the same time a dial-up modem is sending data.

How Information Travels Over the Internet

All information is transmitted across the Internet in small units of data called packets. Software on the sending computer divides a large document into many packets for transmission; software on the receiving computer regroups incoming packets into the original document. Similar to a postcard, each packet has two parts: a packet header specifying the computer to which the packet should be delivered, and a packet payload containing the data being sent. The header also specifies how the data in the packet should be combined with the data in other packets by recording which piece of a document is contained in the packet.

 A series of rules known as computer communication protocols specify how packet headers are formed and how packets are processed. The set of protocols used for the Internet are named TCP/IP after the two most important protocols in the set: the Transmission Control Protocol and the Internet Protocol. Hardware devices that connect networks in the Internet are called IP routers because they follow the IP protocol when forwarding packets. A router examines the header in each packet that arrives to determine the packet’s destination. The router either delivers the packet to the destination computer across a local network or forwards the packet to another router that is closer to the final destination. Thus, a packet travels from router to router as it passes through the Internet.

TCP/IP protocols enable the Internet to automatically detect and correct transmission problems. For example, if any network or device malfunctions, protocols detect the failure and automatically find an alternative path for packets to avoid the malfunction. Protocol software also ensures that data arrives complete and intact. If any packets are missing or damaged, protocol software on the receiving computer requests that the source resend them. Only when the data has arrived correctly does the protocol software make it available to the receiving application program, and therefore to the user.

Network Names and Addresses

To be connected to the Internet, a computer must be assigned a unique number, known as its IP (Internet Protocol) address. Each packet sent over the Internet contains the IP address of the computer to which it is being sent. Intermediate routers use the address to determine how to forward the packet. Users almost never need to enter or view IP addresses directly. Instead, to make it easier for users, each computer is also assigned a domain name; protocol software automatically translates domain names into IP addresses. For example, the domain name encarta.msn.com specifies a computer owned by Microsoft (names ending in .com are assigned to computers owned by commercial companies), and the corresponding IP address is 207.46.228.91. See also Domain Name System.

Users encounter domain names when they use applications such as the World Wide Web. Each page of information on the Web is assigned a URL (Uniform Resource Locator) that includes the domain name of the computer on which the page is located. For example, a user can enter the URL

http://encarta.msn.com/category/physcience.asp

to specify a page in the domain encarta.msn.com. Other items in the URL give further details about the page. For example, the string http specifies that a browser should use the http protocol, one of many TCP/IP protocols, to fetch the item. The string category/physcience.asp specifies a particular document.

Client/Server Architecture

Electronic Mail and News Groups

Internet applications, such as the Web, are based on the concept of client/server architecture. In a client/server architecture, some application programs act as information providers (servers), while other application programs act as information receivers (clients). The client/server architecture is not one-to-one. That is, a single client can access many different servers, and a single server can be accessed by a number of different clients. Usually, a user runs a client application, such as a Web browser, that contacts one server at a time to obtain information. Because it only needs to access one server at a time, client software can run on almost any computer, including small handheld devices such as personal organizers and cellular telephones (these devices are sometimes called Web appliances). To supply information to others, a computer must run a server application. Although server software can run on any computer, most companies choose large, powerful computers to run server software because the company expects many clients to be in contact with its server at any given time. A faster computer enables the server program to return information with less delay.

Electronic mail, or e-mail, is a widely used Internet application that enables individuals or groups of individuals to quickly exchange messages, even if the users are geographically separated by large distances. A user creates an e-mail message and specifies a recipient using an e-mail address, which is a string consisting of the recipient’s login name followed by an @ (at) sign and then a domain name. E-mail software transfers the message across the Internet to the recipient’s computer, where it is placed in the specified mailbox, a file on the hard drive. The recipient uses an e-mail application to view and reply to the message, as well as to save or delete it. Because e-mail is a convenient and inexpensive form of communication, it has dramatically improved personal and business communications.

In its original form, e-mail could only be sent to recipients named by the sender, and only text messages could be sent. E-mail has been extended in two ways, and is a much more powerful tool. Software has been invented that can automatically propagate to multiple recipients a message sent to a single address. Known as a mail gateway or list server, such software allows individuals to join or leave a mail list at any time. Such software can be used to create lists of individuals who will receive announcements about a product or service or to create online discussion groups. Of particular interest are Network News discussion groups (newsgroups) that were originally part of the Usenet network. Thousands of newsgroups exist, on an extremely wide range of subjects. Messages to a newsgroup are not sent directly to each user. Instead, an ordered list is disseminated to computers around the world that run news server software. Newsgroup application software allows a user to obtain a copy of selected articles from a local news server or to use e-mail to post a new message to the newsgroup. The system makes newsgroup discussions available worldwide.

E-mail software has also been extended to allow the transfer of nontext documents, such as graphics and other images, executable computer programs, and prerecorded audio. Such documents, appended to an e-mail message, are called attachments. The standard used for encoding attachments is known as Multipurpose Internet Mail Extensions (MIME). Because the Internet e-mail system only transfers printable text, MIME software encodes each document using printable letters and digits before sending it and then decodes the item when e-mail arrives. Most significantly, MIME allows a single message to contain multiple items, allowing a sender to include a cover letter that explains each of the attachments.

Other Internet Applications

Although the World Wide Web is the most popular application, other Internet applications are widely used. For example, the Telnet application enables a user to interactively access a remote computer. Telnet gives the appearance that the user’s keyboard and screen are connected directly to the remote computer. For example, a businessperson who is visiting a location that has Internet access can use Telnet to contact their office computer. Doing so is faster and less expensive than using dial-up modems.

The Internet can also be used to transfer telephone calls using an application known as IP-telephony. This application requires a special phone that digitizes voice and sends it over the Internet to a second IP telephone. Another application, known as the File Transfer Protocol (FTP), is used to download files from an Internet site to a user’s computer. The FTP application is often automatically invoked when a user downloads an updated version of a piece of software. Applications such as FTP have been integrated with the World Wide Web, making them transparent so that they run automatically without requiring users to open them. When a Web browser encounters a URL that begins with ftp:// it automatically uses FTP to access the item.

Bandwidth

Computers store all information as binary numbers. The binary number system uses two binary digits, 0 and 1, which are called bits. The amount of data that a computer network can transfer in a certain amount of time is called the bandwidth of the network and is measured in kilobits per second (kbps) or megabits per second (mbps). A kilobit is 1 thousand bits; a megabit is 1 million bits. A dial-up telephone modem can transfer data at rates up to 56 kbps; DSL and cable modem connections are much faster and can transfer at several mbps. The Internet connections used by businesses often operate at 155 mbps, and connections between routers in the heart of the Internet may operate at rates from 2,488 to 9,953 mbps (9.953 gigabits per second) The terms wideband or broadband are used to characterize networks with high capacity and to distinguish them from narrowband networks, which have low capacity.

HISTORY

Research on dividing information into packets and switching them from computer to computer began in the 1960s. The U.S. Department of Defense Advanced Research Projects Agency (ARPA) funded a research project that created a packet switching network known as the ARPANET. ARPA also funded research projects that produced two satellite networks. In the 1970s ARPA was faced with a dilemma: Each of its networks had advantages for some situations, but each network was incompatible with the others. ARPA focused research on ways that networks could be interconnected, and the Internet was envisioned and created to be an interconnection of networks that use TCP/IP protocols. In the early 1980s a group of academic computer scientists formed the Computer Science NETwork, which used TCP/IP protocols. Other government agencies extended the role of TCP/IP by applying it to their networks: The Department of Energy’s Magnetic Fusion Energy Network (MFENet), the High Energy Physics NETwork (HEPNET), and the National Science Foundation NETwork (NSFNET).

In the 1980s, as large commercial companies began to use TCP/IP to build private internets, ARPA investigated transmission of multimedia—audio, video, and graphics—across the Internet. Other groups investigated hypertext and created tools such as Gopher that allowed users to browse menus, which are lists of possible options. In 1989 many of these technologies were combined to create the World Wide Web. Initially designed to aid communication among physicists who worked in widely separated locations, the Web became immensely popular and eventually replaced other tools. Also during the late 1980s, the U.S. government began to lift restrictions on who could use the Internet, and commercialization of the Internet began. In the early 1990s, with users no longer restricted to the scientific or military communities, the Internet quickly expanded to include universities, companies of all sizes, libraries, public and private schools, local and state governments, individuals, and families.

THE FUTURE OF THE INTERNET

Several technical challenges must be overcome if the Internet is to continue growing at the current phenomenal rate. The primary challenge is to create enough capacity to accommodate increases in traffic. Internet traffic is increasing as more people become Internet users and existing users send ever greater amounts of data. If the volume of traffic increases faster than the capacity of the network increases, congestion will occur, similar to the congestion that occurs when too many cars attempt to use a highway. To avoid congestion, researchers have developed technologies such as Dense Wave Division Multiplexing (DWDM) that transfer more bits per second across an optical fiber. The speed of routers and other packet handling equipment must also increase to accommodate growth. In the short term, researchers are developing faster electronic processors; in the long term, new technologies will be required.

Another challenge involves IP addresses. Although the original protocol design provided addresses for up to 4.29 billion individual computers, the addresses have begun to run out because they were assigned in blocks. Researchers developed technologies such as Network Address Translation (NAT) to conserve addresses. NAT allows multiple computers at a residence to “share” a single Internet address. Engineers have also planned a next-generation of IP, called IPv6, that will handle many more addresses than the current version.

Short, easy-to-remember domain names are also in short supply. Many domain names that use the simple format http://www.[word].com, where [word] is a common noun or verb, are already in use. Currently, only a few endings are allowed, such as .com, .org, and .net. In the near future, additional endings will be allowed, such as .biz and .info. This will greatly expand the number of possible URLs.

Other important questions concerning Internet growth relate to government controls, especially taxation and censorship. Because the Internet has grown so rapidly, governments have had little time to pass laws that control its deployment and use, impose taxes on Internet commerce, or otherwise regulate content. Many Internet users in the United States view censorship laws as an infringement on their constitutional right to free speech. In 1996 the Congress of the United States passed the Communications Decency Act, which made it a crime to transmit indecent material over the Internet. The act resulted in an immediate outcry from users, industry experts, and civil liberties groups opposed to such censorship. In 1997 the Supreme Court of the United States declared the act unconstitutional because it violated First Amendment rights to free speech. Lawmakers responded in 1998 by passing a narrower antipornography bill, the Child Online Protection Act (COPA). COPA required commercial Web sites to ensure that children could not access material deemed harmful to minors. In 1999 a federal judge blocked COPA as well, ruling that it would dangerously restrict constitutionally protected free speech.

Increasing commercial use of the Internet has heightened security and privacy concerns. With a credit or debit card, an Internet user can order almost anything from an Internet site and have it delivered to their home or office. Companies doing business over the Internet need sophisticated security measures to protect credit card, bank account, and social security numbers from unauthorized access as they pass across the Internet. Any organization that connects its intranet to the global Internet must carefully control the access point to ensure that outsiders cannot disrupt the organization’s internal networks or gain unauthorized access to the organization’s computer systems and data. The questions of government control and Internet security will continue to be important as the Internet grows.