How does the internet work перевод текста
How does the internet work перевод текста
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History of the Internet
From its very beginnings the Internet became a crucial part of each and any infrastructure. Similar to the discoveries of electricity, microorganisms or elementary particles, the creation of the Internet has turned a new page in the history of humanity.
The history of the Internet has begun in the middle of the 20th century as a result of rapid development of computer science. Computers of that age were still relatively underperforming and needed constant maintenance. Some kind of an effective and automated method of time-sharing between users needed to be devised and implemented for them to work reliably.
The first idea that had emerged from that necessity was a concept of multi-tasking. Nowadays we don’t pay much attention to the fact that our computers perform many tasks at once, and that with our computers we can, for example, work and listen to music at the same time. But in the 1950s this idea turned out to be revolutionary.
The second idea would be a proposition to merge multiple computers into a single network. Each participant 1 of such a network would be able to exchange data with the others. But the exact mechanism of implementation was still largely a mystery. Roughly for ten years the scientists were developing and discarding all kinds of ideas, one after another, preserving those that could be at least somewhat handy bit by bit. This is how the prototypes of packet exchange protocols (as well as the concept of a data packet itself) came to be.
In 1969 a duo of American engineers, Robert Taylor and Lawrence Roberts, have made a presentation to the U. S. Department of Defence with a project dubbed 2 ARPANET (which stands for Advanced Research Projects Agency Network) founded on the previous research. Even more advanced networks have started to develop based on this one, including what would be later known as ‘networks of networks’. These researches have culminated with the emergence 3 of two main network protocols (TCP and IP), which are still used as of today with some modifications.
A modern solution that eventually replaced ARPANET was called NSFNET, which was the National Science Foundation Network. This particular network has adopted the TCP/IP protocol as its main one, and also helped the emergence of the Domain Name System (DNS). And thus when the 1990s have arrived, the Internet architecture as we know it was largely in place.
In 2020 nearly 4,5 billion people are using the Internet both for work and communication. The Internet is a cornerstone of all modern banking, of the vital infrastructure automated systems, and also of many computer science branches. This promising technology still continues its development nowadays, and for now we can’t even fathom 5 what new discoveries this further development can bring.
История интернета
С момента своего появления интернет стал незаменимой частью любой инфраструктуры. Подобно открытию электричества, микроорганизмов или элементарных частиц, создание интернета открыло новую страницу в истории человечества.
История интернета началась в середине ХХ века как следствие стремительного развития информатики. Компьютеры тогда всё ещё обладали относительно низкой производительностью и нуждались в частом обслуживании. Для надёжной работы необходимо было придумать и реализовать какой-то способ эффективного и автоматического разделения времени между пользователями.
Первой идеей, родившейся из этой необходимости, было понятие многозадачности. Сейчас мы особо не задумываемся о том, что наши компьютеры совершают множество операций одновременно, и что мы на наших компьютерах можем, например, одновременно работать и слушать музыку. Но в 50-е годы ХХ века эта идея оказалась революционной.
Второй идеей было предложение объединить несколько компьютеров в одну сеть. Каждый участник такой сети мог бы обмениваться данными с остальными. Но как это возможно было бы сделать, толком пока никто не представлял. Около десяти лет учёные разрабатывали и отбрасывали одну за другой различные идеи, отбирая по крупицам то, что могло представлять хоть какую-то ценность. Так появились прототипы протоколов обмена пакетами (как и само понятие пакета данных, передаваемого по сети).
В 1969 году два американских инженера, Роберт Тейлор и Лоуренс Робертс, опираясь на предыдущие разработки учёных, презентовали Министерству обороны США проект ARPANET (название расшифровывалось как «Сеть взаимодействия передовых исследовательских проектов»). На базе этой сети стали разрабатываться другие, более продвинутые сети, в том числе и то, что в будущем назовут «сети сетей». Результатом этих разработок стало появление двух главных сетевых протоколов – TCP и IP – которые в несколько модифицированном виде используются и на сегодняшний день.
Более современным решением, заменившим в конечном счёте ARPANET, стала NSFNET, сеть Национального научного фонда США. Именно в этой сети произошло принятие протокола TCP/IP как основного, а также возникла современная система доменных имён (DNS). Так к началу 90-х архитектура интернета получила свой современный облик.
Следует различать понятия «интернет» и «всемирная паутина». Первое относится именно к архитектуре сетей как таковой. Второе – более современная разработка, представляющая собой интерфейс для доступа пользователей к сети. Появилась она в 1990 году усилиями учёных CERN, в особенности – Тима Бернерса-Ли. Именно ему мы обязаны таким терминам как HTTP, HTML, а также появлением веб-браузеров.
В 2020 году интернетом для работы и общения пользуются около 4,5 миллиардов человек. Интернет является краеугольным камнем работы всех современных банковских систем, автоматизированных систем жизненно важных объектов инфраструктуры, а также множества компьютерных дисциплин. Эта перспективная технология продолжает развиваться и сегодня, и пока что невозможно даже предугадать, к каким новым открытиям приведёт её дальнейшее развитие.
Подсказки:
В английском языке написание the Internet (с артиклем и с большой буквы) связано с исторической необходимость дифференцировать возникающую в конце 80-х годов глобальную сеть с самим способом объединения компьютеров в сети (который можно было бы охарактеризовать как an internet). С приходом интернета в повседневность, англоязычные источники всё чаще пишут слово internet с маленькой буквы. Употреблять определённый артикль считается хорошим тоном, но это правило начинает приобретать свои исключения. Например: Do you have Internet? Контекстно здесь имеется в виду именно доступ к интернету, и артикль не ставится, так как в противном случае вопрос означал бы: «Владеешь ли ты Интернетом (глобальной сетью)?»
В русском языке допустимы варианты написания как с большой, так и с маленькой букв.
How Does the Internet Work?
Contents
Introduction
This whitepaper explains the underlying infrastructure and technologies that make the Internet work. It does not go into great depth, but covers enough of each area to give a basic understanding of the concepts involved. For any unanswered questions, a list of resources is provided at the end of the paper. Any comments, suggestions, questions, etc. are encouraged and may be directed to the author at rshuler@gobcg.com.
Where to Begin? Internet Addresses
The picture below illustrates two computers connected to the Internet; your computer with IP address 1.2.3.4 and another computer with IP address 5.6.7.8. The Internet is represented as an abstract object in-between. (As this paper progresses, the Internet portion of Diagram 1 will be explained and redrawn several times as the details of the Internet are exposed.)
| Diagram 1 |
If you connect to the Internet through an Internet Service Provider (ISP), you are usually assigned a temporary IP address for the duration of your dial-in session. If you connect to the Internet from a local area network (LAN) your computer might have a permanent IP address or it might obtain a temporary one from a DHCP (Dynamic Host Configuration Protocol) server. In any case, if you are connected to the Internet, your computer has a unique IP address.
Protocol Stacks and Packets
| Protocol Layer | Comments |
|---|---|
| Application Protocols Layer | Protocols specific to applications such as WWW, e-mail, FTP, etc. |
| Transmission Control Protocol Layer | TCP directs packets to a specific application on a computer using a port number. |
| Internet Protocol Layer | IP directs packets to a specific computer using an IP address. |
| Hardware Layer | Converts binary packet data to network signals and back. (E.g. ethernet network card, modem for phone lines, etc.) |
If we were to follow the path that the message «Hello computer 5.6.7.8!» took from our computer to the computer with IP address 5.6.7.8, it would happen something like this:
Networking Infrastructure
So now you know how packets travel from one computer to another over the Internet. But what’s in-between? What actually makes up the Internet? Let’s look at another diagram:
| Diagram 3 |
Here we see Diagram 1 redrawn with more detail. The physical connection through the phone network to the Internet Service Provider might have been easy to guess, but beyond that might bear some explanation.
The ISP maintains a pool of modems for their dial-in customers. This is managed by some form of computer (usually a dedicated one) which controls data flow from the modem pool to a backbone or dedicated line router. This setup may be refered to as a port server, as it ‘serves’ access to the network. Billing and usage information is usually collected here as well.
After your packets traverse the phone network and your ISP’s local equipment, they are routed onto the ISP’s backbone or a backbone the ISP buys bandwidth from. From here the packets will usually journey through several routers and over several backbones, dedicated lines, and other networks until they find their destination, the computer with address 5.6.7.8. But wouldn’t it would be nice if we knew the exact route our packets were taking over the Internet? As it turns out, there is a way.
Internet Infrastructure
The Internet backbone is made up of many large networks which interconnect with each other. These large networks are known as Network Service Providers or NSP s. Some of the large NSPs are UUNet, CerfNet, IBM, BBN Planet, SprintNet, PSINet, as well as others. These networks peer with each other to exchange packet traffic. Each NSP is required to connect to three Network Access Points or NAP s. At the NAPs, packet traffic may jump from one NSP’s backbone to another NSP’s backbone. NSPs also interconnect at Metropolitan Area Exchanges or MAE s. MAEs serve the same purpose as the NAPs but are privately owned. NAPs were the original Internet interconnect points. Both NAPs and MAEs are referred to as Internet Exchange Points or IX s. NSPs also sell bandwidth to smaller networks, such as ISPs and smaller bandwidth providers. Below is a picture showing this hierarchical infrastructure.
| Diagram 4 |
This is not a true representation of an actual piece of the Internet. Diagram 4 is only meant to demonstrate how the NSPs could interconnect with each other and smaller ISPs. None of the physical network components are shown in Diagram 4 as they are in Diagram 3. This is because a single NSP’s backbone infrastructure is a complex drawing by itself. Most NSPs publish maps of their network infrastructure on their web sites and can be found easily. To draw an actual map of the Internet would be nearly impossible due to it’s size, complexity, and ever changing structure.
The Internet Routing Hierarchy
Routers are packet switches. A router is usually connected between networks to route packets between them. Each router knows about it’s sub-networks and which IP addresses they use. The router usually doesn’t know what IP addresses are ‘above’ it. Examine Diagram 5 below. The black boxes connecting the backbones are routers. The larger NSP backbones at the top are connected at a NAP. Under them are several sub-networks, and under them, more sub-networks. At the bottom are two local area networks with computers attached.
| Diagram 5 |
When a packet arrives at a router, the router examines the IP address put there by the IP protocol layer on the originating computer. The router checks it’s routing table. If the network containing the IP address is found, the packet is sent to that network. If the network containing the IP address is not found, then the router sends the packet on a default route, usually up the backbone hierarchy to the next router. Hopefully the next router will know where to send the packet. If it does not, again the packet is routed upwards until it reaches a NSP backbone. The routers connected to the NSP backbones hold the largest routing tables and here the packet will be routed to the correct backbone, where it will begin its journey ‘downward’ through smaller and smaller networks until it finds it’s destination.
Domain Names and Address Resolution
Many computers connected to the Internet host part of the DNS database and the software that allows others to access it. These computers are known as DNS servers. No DNS server contains the entire database; they only contain a subset of it. If a DNS server does not contain the domain name requested by another computer, the DNS server re-directs the requesting computer to another DNS server.
| Diagram 6 |
The Domain Name Service is structured as a hierarchy similar to the IP routing hierarchy. The computer requesting a name resolution will be re-directed ‘up’ the hierarchy until a DNS server is found that can resolve the domain name in the request. Figure 6 illustrates a portion of the hierarchy. At the top of the tree are the domain roots. Some of the older, more common domains are seen near the top. What is not shown are the multitude of DNS servers around the world which form the rest of the hierarchy.
When an Internet connection is setup (e.g. for a LAN or Dial-Up Networking in Windows), one primary and one or more secondary DNS servers are usually specified as part of the installation. This way, any Internet applications that need domain name resolution will be able to function correctly. For example, when you enter a web address into your web browser, the browser first connects to your primary DNS server. After obtaining the IP address for the domain name you entered, the browser then connects to the target computer and requests the web page you wanted.
If you use Dial-Up Networking:
Open your Dial-Up Networking window (which can be found in Windows Explorer under your CD-ROM drive and above Network Neighborhood). Right click on your Internet connection and click Properties. Near the bottom of the connection properties window press the TCP/IP Settings. button.
If you have a permanent connection to the Internet:
Right click on Network Neighborhood and click Properties. Click TCP/IP Properties. Select the DNS Configuration tab at the top.
You should now be looking at your DNS servers’ IP addresses. Here you may disable DNS or set your DNS servers to 0.0.0.0. (Write down your DNS servers’ IP addresses first. You will probably have to restart Windows as well.) Now enter an address into your web browser. The browser won’t be able to resolve the domain name and you will probably get a nasty dialog box explaining that a DNS server couldn’t be found. However, if you enter the corresponding IP address instead of the domain name, the browser will be able to retrieve the desired web page. (Use ping to get the IP address prior to disabling DNS.) Other Microsoft operating systems are similar.
Internet Protocols Revisited
Application Protocols: HTTP and the World Wide Web
HTTP is a connectionless text based protocol. Clients (web browsers) send requests to web servers for web elements such as web pages and images. After the request is serviced by a server, the connection between client and server across the Internet is disconnected. A new connection must be made for each request. Most protocols are connection oriented. This means that the two computers communicating with each other keep the connection open over the Internet. HTTP does not however. Before an HTTP request can be made by a client, a new connection must be made to the server.
When you type a URL into a web browser, this is what happens:
and press Enter twice. This is a simple HTTP request to a web server for it’s root page. You should see a web page flash by and then a dialog box should pop up to tell you the connection was lost. If you’d like to save the retrieved page, turn on logging in the Telnet program. You may then browse through the web page and see the HTML that was used to write it.
Most Internet protocols are specified by Internet documents known as a Request For Comments or RFC s. RFCs may be found at several locations on the Internet. See the Resources section below for appropriate URL’s. HTTP version 1.0 is specified by RFC 1945.
Application Protocols: SMTP and Electronic Mail
When you open your mail client to read your e-mail, this is what typically happens:
Transmission Control Protocol
TCP works like this:
| Diagram 7 |
Notice that there is no place for an IP address in the TCP header. This is because TCP doesn’t know anything about IP addresses. TCP’s job is to get application level data from application to application reliably. The task of getting data from computer to computer is the job of IP.
| FTP | 20/21 |
| Telnet | 23 |
| SMTP | 25 |
| HTTP | 80 |
| Quake III Arena | 27960 |
Internet Protocol
| Diagram 8 |
Above we see the IP addresses of the sending and receiving computers in the IP header. Below is what a packet looks like after passing through the application layer, TCP layer, and IP layer. The application layer data is segmented in the TCP layer, the TCP header is added, the packet continues to the IP layer, the IP header is added, and then the packet is transmitted across the Internet.
Wrap Up
Rus Shuler, 1998
Updates made 2002
Resources
http://www.ietf.org/ is the home page of the Internet Engineering Task Force. This body is greatly responsible for the development of Internet protocols and the like.
http://www.internic.org/ is the organization responsible for administering domain names.
http://www.nexor.com/public/rfc/index/rfc.html is an excellent RFC search engine useful for finding any RFC.
http://www.internetweather.com/ shows animated maps of Internet latency.
http://routes.clubnet.net/iw/ is Internet Weather from ClubNET. This page shows packet loss for various carriers.
http://navigators.com/isp.html is Russ Haynal’s ISP Page. This is a great site with links to most NSPs and their backbone infrastructure maps.
Bibliography
How does the Internet work?
By: Jonathan Strickland | Updated: Apr 13, 2021
Even though the Internet is still a young technology, it’s hard to imagine life without it now. Every year, engineers create more devices to integrate with the Internet. This network of networks crisscrosses the globe and even extends into space. But what makes it work?
To understand the Internet, it helps to look at it as a system with two main components. The first of those components is hardware. That includes everything from the cables that carry terabits of information every second to the computer sitting in front of you.
All of this hardware wouldn’t create a network without the second component of the Internet: the protocols. Protocols are sets of rules that machines follow to complete tasks. Without a common set of protocols that all machines connected to the Internet must follow, communication between devices couldn’t happen. The various machines would be unable to understand one another or even send information in a meaningful way. The protocols provide both the method and a common language for machines to use to transmit data.
We’ll take a closer look at protocols and how information travels across the Internet on the next page.
A Matter of Protocols
What do these protocols do? At their most basic level, these protocols establish the rules for how information passes through the Internet. Without these rules, you would need direct connections to other computers to access the information they hold. You’d also need both your computer and the target computer to understand a common language.
You’ve probably heard of IP addresses. These addresses follow the Internet protocol. Each device connected to the Internet has an IP address. This is how one machine can find another through the massive network.
The version of IP most of us use today is IPv4, which is based on a 32-bit address system. There’s one big problem with this system: We’re running out of addresses. That’s why the Internet Engineering Task Force (IETF) decided back in 1991 that it was necessary to develop a new version of IP to create enough addresses to meet demand. The result was IPv6, a 128-bit address system. That’s enough addresses to accommodate the rising demand for Internet access for the foreseeable future [source: Opus One].
When you want to send a message or retrieve information from another computer, the TCP/IP protocols are what make the transmission possible. Your request goes out over the network, hitting domain name servers (DNS) along the way to find the target server. The DNS points the request in the right direction. Once the target server receives the request, it can send a response back to your computer. The data might travel a completely different path to get back to you. This flexible approach to data transfer is part of what makes the Internet such a powerful tool.
Let’s take a closer look at how information travels across the Internet.
Packet, Packet, Who’s Got the Packet?
In order to retrieve this article, your computer had to connect with the Web server containing the article’s file. We’ll use that as an example of how data travels across the Internet.
First, you open your Web browser and connect to our Web site. When you do this, your computer sends an electronic request over your Internet connection to your Internet service provider (ISP). The ISP routes the request to a server further up the chain on the Internet. Eventually, the request will hit a domain name server (DNS).
This server will look for a match for the domain name you’ve typed in (such as www.howstuffworks.com). If it finds a match, it will direct your request to the proper server’s IP address. If it doesn’t find a match, it will send the request further up the chain to a server that has more information.
When the packets get to you, your device arranges them according to the rules of the protocols. It’s kind of like putting together a jigsaw puzzle. The end result is that you see this article.
Translate into English. Интернет – это сеть сетей
Интернет – это сеть сетей. Он соединяет миллионы компьютеров по всему миру, создавая сеть, в которой любой компьютер может общаться с любым другим компьютером, до тех пор, пока они оба подключены к Интернету.
Всемирная паутина или просто Сеть – это глобальное информационное пространство, основанное на физической инфраструктуре Интернета и протоколе передачи данных HTTP. Сеть также использует браузеры, такие как Firefox для доступа к сетевым документам, называемым веб-станицами, которые соединены друг с другом через гиперссылки. Веб-станицы так же содержат графику, музыку, видео. Всем этим можно поделиться путем выгрузки и загрузки файлов.
Интернет, но не Сеть, так же используется для отсылки электронной почты.
23. Watch the video “What the Internet is doing to our brains” making notes while watching. Consult the transcript if you need. Express Nicholas Carr’s main idea. What are the problem and the solution?
The history of the Internet
The Internet in the year 2009. We send e-mails, make calls over the internet and discuss topics we take an interest in. Even our banking is going virtual. But what we take for granted today was only a vague idea fifty years ago. In order to understand how we got this far let’s go back to 1957, when everything began.
Before 1957 computers only worked on one task at a time. This is called batch processing. Of course, this was quite ineffective. With computers getting bigger and bigger they had to be stored in special cooled rooms. But then the developers couldn’t work directly on the computers anymore – specialists had to be called in to connect them. Programming at that time meant a lot of manual work and the indirect connection to the computers led to a lot of bugs, wasting time and fraying the developers´ nerves. The year 1957 marked a big change. A remote connection had to be installed so the developers could work directly on the computers. At the same time the idea of time-sharing came up. This is the first concept in computer technology to share the processing power of one computer with multiple users.
On October 4th 1957, during the Cold War the first unmanned satellite, Sputnik 1, was sent into orbit by the Soviet Union. The fear of a «Missile Gap» emerged. In order to secure America’s lead in technology, the US founded the «Defense Advanced Research Project Agency» in February 1958. At that time, knowledge was only transferred by people. The DARPA planned a large-scale computer network in order to accelerate knowledge transfer and avoid the doubling up of already existing research. This network would become the Arpanet. Furthermore three other concepts were to be developed, which are fundamental for the history of the Internet: The concept of a military network by the RAND Corporation in America. The commercial network of the National Physical Laboratory in England. And the scientific network, Cyclades, in France. The scientific, military and commercial approaches of these concepts are the foundations for our modern Internet.
Let’s begin with the Arpanet, the most familiar of these networks. Its development began in 1966. Universities were generally quite cautious about sharing their computers. Therefore small computers were put on front of the mainframe. This computer, the Interface Message Processor, took over control of the network activities, while the mainframe was only in charge of the initialization of programs and data files. At the same time, the IMP also served as interface for the mainframe. Since only the IMPs were interconnected in a network this was also called IMP-subnet.
For the first connections between the computers the Network Working Group developed the Network Control Protocol [Network Control Program]. Later on, the NCP was replaced by the more efficient Transmission Control Protocol. The specific feature of the TCP is the verification of the file transfer. Let’s take a short detour to England. Since the NPL network was designed on a commercial basis a lot of users and file transfer were expected. In order to avoid congestion of the lines, the sent files were divided into smaller packets which were put together again at the receiver. «Packet Switching» was born!
In 1962 American ferret aircrafts discovered middle and long range missiles in Cuba, which were able to reach the United States. This stoked fear of an atomic conflict. At that time information systems had a centralized network architecture. To avoid the breakdown during an attack, a decentralized network architecture had to be developed, which in case of loss of a node would still be operative. Communication still used to work through radio waves that would have caused problems in case of an atomic attack: the ionosphere would be affected and the long-wave radio waves wouldn’t work anymore. Therefore they had to use direct waves, which, however, don’t have a long range. A better solution was the model of a distributed network. Thus long distances could be covered with a minimum of interference.
Another milestone followed with the development of the French network «Cyclades». Since Cyclades had a far smaller budget than Arpanet and thus also fewer nodes the focus was laid on the communication with other networks. In this way the term «inter-net» was born. Moreover, Cyclades´ concept went further than ARPA’s and the NPL’s. During communication between sender and receiver the computers were not to intervene anymore, but simply serve as a transfer node. Cyclades´ protocol went through all machines using a physical layer that was implemented into the hardware, providing a direct connection with the receiver – an end-to-end structure. Inspired by the Cyclades network and driven by the incompatibility between the networks, their connection gained in importance everywhere.
The phone companies developed the X.25 protocol which enabled communication through their servers – in exchange for monthly basic charge of course.
DARPA’s Transmission Control Protocol was to connect the computers through gateways. and the International Organization for Standardization designed the OSI Reference Model. The innovation of OSI was the attempt to standardize the network from its ends and the channel’s division into separate layers. Finally, the TCP assimilated the preferences of the OSI Reference Model and gave way to the TCP/IP protocol – a standard which guaranteed compatibility between networks and finally merged them, creating the Internet. By February 28, 1990 the ARPANET hardware was removed, but the Internet.
. was up and running.
How the Internet Works in 5 Minutes
Whenever most people think of the internet, this is what comes to mind. the internet is not a bubble cloud even in the new age of cloud computing. The whole fuzzy cloud picture was created by people more concerned about job security than education.
This is the internet. The internet is a wire actually buried in the ground. It might be fiber optics, copper or occasionally a beam to satellites or through cell phone networks, but the internet is simply a wire. The internet is useful because two computers connected directly to this wire can communicate. A server is a special computer connected directly to the internet and web pages or files on that server’s hard drives. Every server has a unique internet protocol address or IP address, just like a postal address IP addresses help computers find each other. But since 72.14.205.100 doesn’t exactly roll off the tongue we also give the names like Google.com Facebook.com or Security catalyst.com. So this is how it works.
Whenever an email, picture or webpage travels across the Internet computers break the information into smaller pieces called packets. When information reaches its destination the packets are reassembled in their original order to make a picture, email, webpage or tweet.
Okay, so imagine you’re at work sitting next year boss and you’re both surfing online. Your boss is doing market research and you’re updating your face book profile. You’re both sending packets back-and-forth over the Internet. But what’s to keep your packets from accidentally ending up on your bosses screen? That could be embarrassing! The solution to that problem is IP addresses and routers. Everything connected directly or indirectly to the Internet has an IP address, everything. That includes your computer, servers, cell phones and all of the equipment in between. Anywhere two or more parts of the Internet intersect there’s a piece of equipment called a router. Routers direct your packets around the internet helping each packet get one step closer to its destination. Every time you visit a website, upwards of ten to fifteen routers may help your packets find their way to and from your computer. Imagine each packet as a piece of candy wrapped in several layers. The first layer is your computer’s IP address. Your computer sends the packet to the first router which adds its own IP address. Each time the packet reaches a new router another layer is added until it reaches the server. Then when the server sends back information, he creates packets with an identical wrapping. As a packet makes its way over the Internet back to your computer, each router unwraps a layer to discover where to send the packet next, until it reaches your computer and not your bosses. And that’s how the Internet works. In five minutes or less. And you’re now easily in the top ten percent of people who understand the basics of the Internet. If you found this video helpful, check out Security catalyst.com for all kinds of ideas on how to protect your information.
How Does the Internet Work?
When you use the internet what happens? Whether you go online to check with a friend or send e-mails or buy a book or check the weather, watch a movie or study the Peloponnesian war, it feels like one wire connecting you directly to the thing you want. But a billion other people are connecting to the billion other things at the same time. How does that happen? It’s really about making agreements. Think of networking as a game. It only works if we agree to play by the same rules. Otherwise it’s not much fun. If you can get two or more computers to play together you have a network. If your friend can do it too – there’s another network. But if you both agree that your networks will play the same way, now you can hook the two together. You have an inter network.
The rules we play by are called the Internet protocol. And as long as we all agree we can keep adding more devices and more networks until the whole world is connected. That’s what the Internet is – a network of networks that share each other.
Every device on the Internet has its own unique address. Anything you send via Internet is really just a message from one device to another. But it doesn’t travel in one big blank. It gets polarised in tiny packets of data each one wrapped in info about what it is: where it came from and where it’s going. This way, your one message can actually take several different paths to its destination. Then by following the protocol the receiving device knows how to put it all back together. The strength of the Internet is that it’s decentralized. With so many possible connections there’s no single point of failure. If one path gets overloaded or broken your data just takes a different path. Even if a big chunk of the Internet gets wiped out your message can still find its way.
And let’s say you use one internet provider and your friend is on a different one. How does your data really get from one network to the other? Some companies make private connections with each other to exchange traffic. But more and more traffic is flowing through shared service platforms we called an Internet exchange points. An Internet exchange is the place where many different organisations come together to interconnect their technology. They may be access providers, broadcasters, publishers, social network sites, telecom operators, really anybody who relies on network traffic can benefit from the exchange. By connecting in a common place they save costs and the traffic between them flows faster and much more efficiently. Traditionally, providers have sold each other passage on the networks. But for some providers who regularly exchange traffic all that buying and selling get more trouble than it’s worth. Many of them saw that if they just agree to meet each other halfway, then everybody’s costs go down and the traffic moves more smoothly. Provides are able to make a single connection to the platform to exchange traffic with many participants. This way of doing things is called peering and it’s making the Internet faster and more affordable for everybody. The exchange participants make deals with each other according to mutual benefit, so the peering system tends to regulate itself. It may seem like companies are giving away their services but in fact each is providing their part of the whole solution their customers need to most efficiently and reliably exchange traffic.
The Internet is open, decentralized and totally neutral. Its intelligence lives at the edge not in the core. No single organisation controls it. And that’s why it works as well as it does. By agreeing to co-operate we all make the Internet happen and that’s how the Internet happens.
What the Internet is Doing to Our Brains
So you are reading an article online then you get an instant message with a link to a funny photo, which of course you have to share. And now you are reading your Facebook News Wall, which sends you to a video of a panda bear attacking a kid. And now you are reading Wikipedia to learn everything you can about the violent behavior of panda bears. And this is what 3 minutes on the Internet can be like.
We live like this all the time, and it has to have some kind of effect on us.
The Net is making us more superficial as thinkers. That is Nicholas Carr. He is the author of, «The Shallows: What the Internet is Doing to our Brains.»
It’s an incredibly information rich environment, uh, that the Net creates for us. And that’s why we use it so much. I mean sounds, pictures, words, texts. And what this tends to do is promote a sort of compulsive behavior in which we are constantly checking your smart phone, constantly glancing at our email inbox. We’re kind of living in this perpetual state of distraction and interruption. Which is dangerous because. That mode of thinking crowds out the more contemplative calmer modes of thinking.
And that focused, calm thinking is actually how we learn. It’s a process called memory consolidation. And that means the transfer of information from our short term working memory, to our long term memory. And it’s through moving information from your working memory to your long term memory that you create connections between that information and everything else you know.
So you’ve got this awesome, life changing piece of information in your short term memory, but then you hear that email ding, and poof, there it goes. That email takes its place, and you never get a chance to learn anything, all because of one distraction.
So attention is the key. And if we lose control of our attention, or are constantly dividing our attention, uh, then we don’t really enjoy that consolidation process. But I can hear it now, someone out there is saying, «Uh, what does learning matter if all of the information in the world is just a Google search away?» Well.
Um, that is kind of short-changing our intellects. If that’s the way you’re using your mind, just kind of searching very quickly and finding information and then forgetting it very quickly, you’re never building knowledge. You’re simply, you’re, you’re kind of thinking like a computer, which means that our very humanity is at stake. And it would be a shame if we all got assimilated, because, well, humanity is pretty neat.
I really believe that if you look at the great monuments of culture, they come from people who are able to pay attention, who control their mind. That’s what allows us to think in the highest terms and think conceptually, think critically, uh, think in some very creative ways.
How does the Internet work?
This article discusses what the Internet is and how it works.
| Prerequisites: | None, but we encourage you to read the Article on setting project goals first |
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| Objective: | You will learn the basics of the technical infrastructure of the Web and the difference between Internet and the Web. |
Summary
The Internet is the backbone of the Web, the technical infrastructure that makes the Web possible. At its most basic, the Internet is a large network of computers which communicate all together.
The history of the Internet is somewhat obscure. It began in the 1960s as a US-army-funded research project, then evolved into a public infrastructure in the 1980s with the support of many public universities and private companies. The various technologies that support the Internet have evolved over time, but the way it works hasn’t changed that much: Internet is a way to connect computers all together and ensure that, whatever happens, they find a way to stay connected.
Active Learning
Deeper dive
A simple network
When two computers need to communicate, you have to link them, either physically (usually with an Ethernet cable) or wirelessly (for example with Wi-Fi or Bluetooth systems). All modern computers can sustain any of those connections.
Note: For the rest of this article, we will only talk about physical cables, but wireless networks work the same.
Such a network is not limited to two computers. You can connect as many computers as you wish. But it gets complicated quickly. If you’re trying to connect, say, ten computers, you need 45 cables, with nine plugs per computer!
To solve this problem, each computer on a network is connected to a special tiny computer called a router. This router has only one job: like a signaler at a railway station, it makes sure that a message sent from a given computer arrives at the right destination computer. To send a message to computer B, computer A must send the message to the router, which in turn forwards the message to computer B and makes sure the message is not delivered to computer C.
Once we add a router to the system, our network of 10 computers only requires 10 cables: a single plug for each computer and a router with 10 plugs.
A network of networks
So far so good. But what about connecting hundreds, thousands, billions of computers? Of course a single router can’t scale that far, but, if you read carefully, we said that a router is a computer like any other, so what keeps us from connecting two routers together? Nothing, so let’s do that.
By connecting computers to routers, then routers to routers, we are able to scale infinitely.
Such a network comes very close to what we call the Internet, but we’re missing something. We built that network for our own purposes. There are other networks out there: your friends, your neighbors, anyone can have their own network of computers. But it’s not really possible to set cables up between your house and the rest of the world, so how can you handle this? Well, there are already cables linked to your house, for example, electric power and telephone. The telephone infrastructure already connects your house with anyone in the world so it is the perfect wire we need. To connect our network to the telephone infrastructure, we need a special piece of equipment called a modem. This modem turns the information from our network into information manageable by the telephone infrastructure and vice versa.
So we are connected to the telephone infrastructure. The next step is to send the messages from our network to the network we want to reach. To do that, we will connect our network to an Internet Service Provider (ISP). An ISP is a company that manages some special routers that are all linked together and can also access other ISPs’ routers. So the message from our network is carried through the network of ISP networks to the destination network. The Internet consists of this whole infrastructure of networks.
Finding computers
Internet and the web
As you might notice, when we browse the Web with a Web browser, we usually use the domain name to reach a website. Does that mean the Internet and the Web are the same thing? It’s not that simple. As we saw, the Internet is a technical infrastructure which allows billions of computers to be connected all together. Among those computers, some computers (called Web servers) can send messages intelligible to web browsers. The Internet is an infrastructure, whereas the Web is a service built on top of the infrastructure. It is worth noting there are several other services built on top of the Internet, such as email and IRC.
Intranets and Extranets
Intranets are private networks that are restricted to members of a particular organization. They are commonly used to provide a portal for members to securely access shared resources, collaborate and communicate. For example, an organization’s intranet might host web pages for sharing department or team information, shared drives for managing key documents and files, portals for performing business administration tasks, and collaboration tools like wikis, discussion boards, and messaging systems.
Extranets are very similar to Intranets, except they open all or part of a private network to allow sharing and collaboration with other organizations. They are typically used to safely and securely share information with clients and stakeholders who work closely with a business. Often their functions are similar to those provided by an intranet: information and file sharing, collaboration tools, discussion boards, etc.
Both intranets and extranets run on the same kind of infrastructure as the Internet, and use the same protocols. They can therefore be accessed by authorized members from different physical locations.