What is a global network? Organization of global networks, tools and capabilities What are global networks in brief.
Almost everyone today is familiar with the Internet first-hand. The Internet plays an important role in the modern world and is simply necessary for humanity. To the question of what a global network is, many people know the answer. At its core, a global network is an association of a large number of computers that can work remotely.
Currently, there are rules by which computers can communicate with each other. They can do all this exclusively with the help of the World Wide Web. So, what is the global Internet? The Internet assumes the same method for connecting to the global network for all computers, uniform coding for data transmission and unified system data identification.
Why was the system created?
This system was created, first of all, so that people from different parts of the world have a constant opportunity to communicate with each other, and so that any interruptions in the system are not fatal. To understand what a global computer network is, it is enough to imagine a web. In the middle of the web, the weave is known to be denser - these are the so-called host computers, which constantly receive and send data that comes to them from different ends of the web. Since there are a huge number of host computers, neither viruses, nor hacker attacks, nor power outages will ever be able to “put down” such a global network.
If any host computer suddenly stops working, then all data is automatically redirected to another host, so that all data remains safe. In a modern global network, there are a huge number of host computers, and the number of computers connected to them regular computers There are even more users, although probably not a single ordinary person, going online, even imagines what part global system he becomes.
Let's try to figure out in this article what the Internet is and what it is used for! Nowadays, the Internet has become an integral part of our lives: entertainment and relaxation, work and news, answers to questions and much more! The main value, probably, can be considered the knowledge base, which is only expanding every day!
For an ordinary user like you or me, the Internet is something invisible, but significant, something that makes it possible to exchange digital information and communicate in real time with anywhere in the world!
But on the other hand, the Internet is billions of computers connected to each other by cables and radio waves, it is a whole network connecting everyone and everything into one!
Internet (Internet network, Internet)— a global network of computer resources with collective access based on the use of a single standard addressing scheme, a high-performance backbone and high-speed communication lines with the main networked computers. – Wikipedia
How does the Internet work?
As you managed to understand from the introduction, the Internet is billions of computers connected to each other, cables pass under the oceans under the water column, connecting continents, and then come to the user, but in a modified - simpler way.
The entire Internet connection is primarily built on digital IP addresses! All connections with any device on the network are carried out using protocols (http:, ftp:) this is like a language for computers to communicate with each other.
When you log on to the Internet, start entering the site address you need:
In fact, this address is just a mask under which the same digital IP address is hidden (For example, 12.233.123.7)
So, for example, when downloading a file with your favorite music or the necessary software, you can access a computer (server) that is based (located) in Germany or the USA.
What opportunities does the Internet provide?
The Internet has a wide range of possibilities, I think you probably know half of them, and you have participated in some of them! But the main thing is, of course, the transfer of information, in which it can be static or dynamically changed on the way to its destination! Some information may change throughout its storage, and others may be supplemented!
The main features include:
- Web – Surfing (browsing Internet pages)
- Control remote computers(gives you the opportunity to help or work on another computer)
- Communication (messaging, mail, etc.)
- Data exchange (any files
- Transfer of funds (working with bank accounts)
- Earnings (for example, freelancing)
WWW
WWW – World Wide Web (worldwide web) is a network of interconnected Internet pages on different computers. Several pages related to each other by one topic and located on one computer are called a Site! Typically, Internet pages are text information, but can contain any digital file.
WEB is the most popular service on the Internet. You don’t notice that when you talk about the Internet, you mean WEB! Almost the entire web as it is exists through the use of hyperlinks that move you across pages. You can also easily navigate by entering the resource address in the address bar - this is called a URL (path).
World Wide Web Addressing
Do you know what will happen if you enter the URL incorrectly in the address bar, you will most likely see an inscription stating that this address does not exist - make sure you typed it correctly, BUT there are cases when you type the address you will be taken to a site with advertising or “low-quality” information. In such cases, immediately leave the page and do not open any links; they may contain a virus threat. This type of distribution of virus codes is called Phishing.
The main thing in the address is, of course, the DOMAIN, that is, it is important to enter the name of the site correctly, for examplew-d-x.ru
After which you will be able to navigate within the site using its links, without going beyond one Internet resource.
In fact, a digital number is hidden under the address IP address, which is the true address of the site. It is at this address that the browser (Internet page viewer) downloads the page. Domains were invented to make addresses convenient for remembering and entering.
All translations from a digital address to a clear alphabetic one are handled by special serversDNS (domainnameserver). One of the largestDNS servers are server centerGoogle.
With the advent of the first personal computers their development was closely followed by millions of people around the world. Progress was very rapid and steady. Computer technology entered and forever strengthened in all spheres of society.
Now it is no longer possible to imagine the isolation of any human activity from computer devices. Users spend their leisure time online, the work of millions of offices of commercial and non-profit companies is ensured by computers, the defense and security of entire countries depend on the development of this type of technology.
To achieve all the tasks and goals that the creators of computer devices set for themselves, it was necessary to find a way to connect user stations to each other.
Having gone through a difficult path of development, such methods were found that allow connecting several stations.
- Local networks– allow you to connect stations at a distance of no more than 15 km. In this way, most often, either a single building or several neighboring ones are connected.
- Regional networks– the length of which ranges from 10 to 100 km. A regional network can be either a city or an entire district.
- Global networks – provide connections over 1000 km. They unite regions and even countries. The most famous such network, of course, is the Internet.
There is no need to consider regional networks in this article, since a lot will be said about them at the Svyaz Expocenter exhibition, and information about what they are will be presented here.
Local area network
LANs are very popular in economic sphere, allowing you to combine office workers' stations.
Different connection patterns such as busbar, ring and star are used to achieve the same purpose. The bus represents a scheme in which there is a single central channel, and all users are connected to it. Communication is carried out between all computers on the network.
This scheme pleases with its low connection cost and reliability. If one of the network stations malfunctions, this will not affect the performance of the others.
The bus also has a number of disadvantages, including low data transfer speed and its dependence on the number of network subscribers, as well as extremely low security of information stored on hard drives user stations.
When connecting according to the “ring” scheme, stations are literally connected sequentially in a circle, forming a closed ring. Information in the process of transmitting packet data contacts all users who are connected by the network until it reaches the user with the desired address.
The advantages here are security, speed of data exchange and significant length of connections. Subscribers of such a network are very vulnerable - if one station fails, the communication of the others is lost.
The latest and most popular local network scheme today is the “star”. Stations are connected to a central node (server or hub) and exchange information through it. The advantages here are high speed, separate communication channels and the fact that a malfunction of any station does not affect the performance of the network.
Local and global computer networks is a very important topic at the Communications exhibition at the Expocenter, so the possibilities and advantages of giving client-servers special rights will be discussed there, connection details will be considered, as well as prospects for the development of these networks.
Global Area Networks
Wide Area Networks (WAN) are a way to connect many computers around the world. The connection of a huge number of local and regional networks between many countries made it possible to create the Internet using a colossal number of data transmission channels.
In addition to the most common network, there are others, among which are FidoNet, Eunet, Gren. There are corporate networks, they are created by individual companies in order to protect their own information stored on networked computers of office employees in different countries.
Today, the ability to connect and use local and global computer networks is fundamental when choosing computerized devices for buyers. All gadgets, by modern standards, must provide users with Internet access.
At the exhibition "Communication", which will be held by Expocentre, we will talk about the global significance that the Internet has acquired from its creation to the present day. This is not the first time for this company to hold an event touching on a global topic. The Expo Center annually hosts exhibitions in key areas of society.
Local and global computer networks, undoubtedly deserve attention at the event held by the Expocenter, which will be interesting and informative.
Read our other articles:Today, many users are increasingly faced with the concept of a global computer network. True, not everyone is fully aware of what it is in the broadest sense, and what the capabilities of the global network are, limited to just the Internet. Let's try to understand this issue in a little more detail, and also consider some of the main characteristics that are inherent in such computer structures.
What is a global network: a general concept
Let's start by understanding the very definition of networks of this type. Based on what is proposed in the description by the most famous and respected information sources on the World Wide Web, global networks are understood as organizational structures that connect individual computers or terminals located on a local network with each other, regardless of their physical location. So what is it?
Indeed, this is a certain structure that is capable of ensuring interaction between user terminals or even mobile devices, no matter where in the world they are located. What is most interesting is that such structures refer to virtual concepts, since wired connections between all devices around the world cannot be simply physically established.
Local and global networks: what's the difference?
Some users mistakenly believe that there is no difference between these two concepts. Here it is worth looking at the most important difference between both types of networks.
The local network itself is designed to connect only a strictly defined number of computer devices and cannot interact between them if their number is exceeded. In addition, such networks provide only general access to some programs or documents, and communication is carried out through a central server or several servers.
The organization of global networks in this regard is fundamentally different. They can include individual computers or mobile devices, and entire local networks. In other words, there are no restrictions on the number of simultaneously connected devices (except perhaps by assigning an external identifier to each device, such as an IP address on the Internet, or a number mobile phone). The IPv4 protocol will soon exhaust its capabilities due to the limited number of assigned addresses, but the sixth version, which is replacing the fourth, has such restrictions, if any, then they are very conditional.
Principles of organization
The development of global networks is believed to have begun from the moment when the connection between computer devices tried to install via ARPANET. This network is fundamentally the progenitor modern Internet.
Only at the dawn of the implementation of such an idea, communication was carried out via cables, but over time, solutions for organizing computer interaction reached new level. In simple terms, the structure is such that on one side there is a LAN router for output, and on the other there is a switch for communication with the required parts of the global network.
Types of WANs
If we talk about what a global network is, we cannot help but touch upon the issue of modern types of such computer structures.
Basically, the classification distinguishes several main classes, among which any user knows the following:
- satellite networks;
- mobile networks;
- Internet and its varieties.
How does this work?
As is already clear, access to the global network is provided through device identification, and communication is carried out through the use of special protocols.
The protocols themselves may vary for different networks and different operating systems, but in international standards you can usually find protocols like TCP/IP, ATM, MPLS, SONET/SDH, etc. Each such protocol is a set of specific rules by which access to the global network, information is transmitted and received, or user devices are identified, etc. Note that in this case we are not talking about initializing the user’s persona. All this applies exclusively to computers or mobile devices.
The most famous global networks
In general, today the most popular networks are considered to be the Internet and FidoNet. However, few people realize that networks mobile operators are also unique global structures using GSM technology standards for communication between devices.
What about 3G/4G? Here you need to clearly understand that these standards are used exclusively for accessing the Internet, and, more simply, for connecting one global network to another. And any global network is initially focused on high data transfer speeds, which distinguishes it from a local structure. But today, the networks of mobile operators can equally be classified as both a local and a global network, since they unite only strictly defined devices identified by numbers, and on the other hand, their number is growing day by day, which implies the assignment of such identifiers in almost unlimited quantities.
Some Basic Features and Challenges
But let's see what the global Internet is. It is the structure called the World Wide Web that has become the most popular, developed and extensive. If previously it was focused mainly on sending correspondence in the form email or visiting web pages, today its resources are such that users anywhere in the world can communicate with each other, say, through video chats in real time or social networks, upload information of any type, store your own data in cloud services etc.
One of the most interesting tools is simultaneous access to electronic documents, which involves opening and editing files by several users at once. It goes without saying that any change in the document is immediately displayed on the computers of all currently connected users. What is a global network in this sense? This is a tool that provides software interaction at all levels and between any users.
But the emergence of the World Wide Web, in a sense, gave rise to many problems, since it is on the Internet today that such a huge number of viruses, malicious codes and programs are distributed that it is difficult to imagine. Even the most advanced antivirus developers software they do not have time to monitor their appearance.
Of course, these are not all the possibilities that can be cited as an example. Bitcoin mining, which has been gaining momentum recently, can also be classified as such a tool. Here the technology is such that, via the Internet, you can combine machines into one virtual network even without the consent of their owners and take advantage of a multiple increase in the performance of a single computer by using the computing capabilities of other terminals. Naturally, in a sense, such programs can be called viruses or actions that fall under the jurisdiction of illegal access to other people's information, however, precisely as tools of global networks, such opportunities cannot be discounted.
In addition, it is worth special mentioning network operating systems that do not require installation on hard drive, or can be downloaded to a computer terminal from a remote server, ensuring full operation of any device. It is believed that such technologies are the most relevant today, since the security system used for their structures and remote access is much higher than in stationary systems.
Brief conclusions
In general, I think it is already a little clear what a global network is and how it differs from a local network. Naturally, it is impossible in principle to consider absolutely all the tools provided. However, this, in fact, was not the question. At least from the above material you can understand what these structures are, why they are needed and what basic capabilities they have.
Global computer networks
Global network- This is an extensive communication network, work in which is provided with the help of telecommunications companies.
The main cells of the global network are local area networks . In this case, local networks can be included as components of a regional network, regional networks - as part of a global network. There are also computers that are independently (directly) connected to the global network. They are called host computers.
Global networks, uniting users located in different countries and on different continents, make it possible to solve the problem of uniting the information resources of all humanity and organizing access to these resources.
Currently, there are more than 200 global computer networks registered in the world, but the largest of them is the Internet.
Global computer network Internet
Internet(English) Internet, from lat. inter - between and English net - network) is a global computer network that unites into a single whole many computer networks and individual computers that provide extensive information for general use and is not a commercial organization.
A relatively strict definition of the Internet from a technical point of view can be given as follows: Internet is a metanetwork consisting of many networks that operate according to the TCP/IP family of protocols, are united through gateways, and use a single address space and namespace. Metanetwork - This is a network in which the nature and topology of network connections are different and do not have a strictly defined structure.
Brief history Internet. The birthday of the Internet can be called January 2, 1969 . On this day, the Advanced Research Projects Agency (ARPA) (later renamed DARPA), a division of the US Department of Defense, began work on a project to create a network to provide communications during a nuclear war.
As a result of the research, a network was created ARPAnet, sometimes called the “mother” of the Internet. It initially connected 4 computers of four large US universities. After some time everything more computers began to connect to the ARPAnet, forming an ever-increasing network.
In 1983, the DARPA agency developed network protocols TCP/IP. At the same time, the US government refused to use the ARPAnet network for military purposes and therefore it was divided into two networks: ARPAnet (remained for public needs) and MILnet (became under the control of the military), but the connection made between the networks allowed them to communicate with each other. This first internetwork was called DARPA Internet , later the first word was omitted and such an internetworking became known as Internet.
The next significant step in the development of the Internet is associated with the creation in 1986, based on ARPAnet, of the US National Science Foundation network. NSFnet, which united scientific centers of the United States with five supercomputers.
The development of the network required its reorganization and in 1987 the NSFnet Backbone was created - the base part or backbone of the network, which consisted of 13 centers located in different parts of the United States, connected to each other by high-speed communication lines. NSFnet quickly took the place of ARPAnet, and the latter was disbanded in March 1990. This is how the Internet appeared in the USA.
At the same time, national networks were created in other countries. These networks began to unite with each other, forming a single network of networks (or internetwork), which became known as the Internet.
Internet structure. The physical structure of the Internet is made up of computers of the most different types. Those of them that are constantly connected and participate in the transfer of data between other network participants, providing users with certain services, are called servers. Despite the fact that many of the servers are not software compatible, the entire system functions reliably due to the fact that each server uses the standard TCP/IP data transfer protocol (protocol - This is a set of rules and agreements that allow computers of different types running different operating systems to communicate with each other.
According to the protocol TCP/IP all data transmitted over the network is “split” into small blocks and “embedded” in packets . Each packet, in addition to the data enclosed in it, has a header containing the sender's address, the recipient's address, and other information necessary for the correct assembly of the packets at the destination. Packets move from one server to another and are then forwarded to the next server that is “closer” to the destination. If the packet is transmitted unsuccessfully, the transmission is repeated. In this case, requests are sent from clients to servers, divided into packets, and from servers to clients - the requested data.
If any part of the worldwide network fails, packets of information will automatically bypass the affected area. All transatlantic cables between Europe and America can be cut. Without receiving confirmation of packet delivery, the servers will automatically repeat transmission via satellite channels communications or via networks of radio relay stations.
TCP/IP protocol in fact, there is not one protocol, but two. Protocol TCP (Transmission Control Protocol- Transmission Control Protocol) is responsible for how information is “split” into packets and how it is then assembled into a complete document, and the protocol IP (Internet Protocol- Internet Protocol) is responsible for how these packets are transmitted on the network and how they reach the destination.
Internet addressing. All computers included in worldwide network, work in automatic mode, that is, without the participation of people, but in order to be able to uniquely identify any computer on the Internet, a special address system is used, called IP addresses. Each computer receives its own unique address, which is used when sending information. Internet addresses can be represented either by a sequence of numbers or by a name constructed according to certain rules. Although there is no Internet control center, there are special organizations involved in checking and issuing addresses (for example, the Internet Information Center - InterNIC).
Digital addresses on the Internet consist of 4 numbers, each of which does not exceed 255. When writing, numbers are separated by dots, for example: 207.68.156.58. The address consists of several parts. The beginning of the address determines the part of the Internet to which the computer is connected (in giant “A” class networks, the first number of the address lies in the range from 0 to 127; in large “B” class networks - from 128 to 191; in medium “C” class networks - from 192 to 223; addresses from 224 to 255 are reserved), and the end is the address of the computer on this network.
Computers use digital addresses when sending information, and users use mostly names when using the Internet, since addresses formed from words are much easier to remember. On the Internet it is used like this called the domain (or multi-level) name system (DNS).
DNS (Domain Name System- domain name system) is a database that converts domain names of computers connected to the Internet into numeric IP addresses. When a user enters a domain name, the computer contacts DNS servers, which automatically resolves the domain name into a digital address.
Domain (domain) is a separate level in the multi-level Internet naming system that carries a certain information load. Under the concept domain can be understood as a collection of computers as part of a network, united by some common characteristic (for example, located in the same state, belonging to the same company, etc.). The Internet Domain Name System uses the principle of sequential refinements. The top-level domain is located to the right of the name, and the lower-level domain is to the left. A name can have any number of domains, but the most common names are those with three to five domains. Domains consist of subdomains, the names of which are separated by dots. Often a 1st level domain indicates a country, a 2nd level domain indicates a city, a 3rd level domain indicates a company (organization); if the city name is missing, the company name becomes a 2nd level domain.
In the Internet address home.managers.company.spb.ru domain ru indicates that we are talking about the Russian part of the Internet; in the domain spb.ru subdomain spb- to the city of St. Petersburg, in the domain company.spb.ru subdomain company determines the organization to which the given address belongs, in our case it is the company company; in the domain managers.company.spb.ru subdomain managers indicates a division in a given organization, for us this is a division of managers named managers; one of the computers in this department has been assigned the name home. As a result, the full address of this computer will be home.managers.company.spb.ru.
For lower level domains you can use any address, but for top level domains there is a convention. The Internet address system accepts domains represented by geographic regions (geographic domains). They have a name consisting of two letters. For example, by - Belarus, ri - Russia, ia - Ukraine, us - USA, de- Germany, fr- France, pl- Poland, uk- United Kingdom, jp- Japan, etc.
Historically, in the United States it was not customary to indicate the name of the country, but used designations determined by the type of organization that owns the address, the so-called topic domains . For example, edu- educational institutions, gov- government agencies, hundred - commercial organizations, mil- military organizations, net - network management organizations org- other organizations.
Quite often, the leftmost name in an address indicates the type of information that the address points to. For example, www.microsoft.com indicates the use of WWW.
When working on the Internet, not just a domain address is used, but uniform resource locator (URL).
URL (Uniform Resource Locator) - this is the address of any resource on the Internet indicating which protocol should be used to access it, which program to run on the server and which specific file should be opened.
In general, the URL format can be represented as follows:
protocol://computer network address/path/file name, Where protocol (access method) can have one of the following values: http - file on the WWW server, ftp- file on FTP server, gopher- file on Gopher server, news - Usenet newsgroup, telnet - access to the resources of another computer in remote terminal mode, etc.); computer network address indicates the domain (or IP) address of the computer containing this resource on the Internet.
Currently there are three main Internet access method:
1. Direct connection (dedicated connection) - This is a connection in which an individual or company connects to the backbone of the Internet through a dedicated machine called a gateway. Gateway - This is a specialized computer that provides external communication from one network to another network using a different data transfer protocol.
2. Connecting through someone else's gateway - This is access to the Internet through the gateway of an organization or institution, usually using a modem to connect.
3. Session (dial-up) connection - this connection is through service providers. Switching is the establishment of communication between devices by creating temporary connections.
Service providers - these are companies with Internet gateways that they provide to other companies or individuals for a subscription fee.
Currently, for ordinary users, the most popular way to connect to a global computer network is to connect using a telephone line. Since when typing telephone number To establish communication between two subscribers at the PBX, the communication line is switched (switched), then telephone lines are often called switched. To connect computers to communication lines, you must use special electronic devices- modems (fax modems).
Modem(from words mo duulator and dem modulator) is an information input/output device that provides modulation and demodulation of signals, thus converting PC digital signals into audio signals and back to transmit them over telephone lines communications. Fax modem is a modem combined with a fax machine - a device designed for exchanging symbolic, graphic, video and audio information (i.e. fax messages) via telephone communication channels.
Unit of measurement information transfer speed is 1 bit/sec .
Traffic is the amount of information transmitted over a network over a certain period of time and measured in bits.
For gaining access to the Internet it is necessary, as a rule, to conclude an agreement with one of the many organizations of owners of networks included in the Internet (they are called primary providers), or their dealers (intermediaries). In the Republic of Belarus, the primary provider is the Republican Unitary Telecommunications Enterprise Beltelecom.
