A computer network is nothing more than an association of several computers with each other, allowing them to exchange data. Global networks are called when they cover users from all over the world. Note that the first civilian computer networks appeared in the United States. But few people know that the very principle of this technology was first used in the USSR, and thanks to this, the first missile defense system was created a long time ago.
Today there is a fairly broad classification of networks. According to the territorial prevalence, global, local and regional computer networks are distinguished. Global computer networks are networks located on the territory of a state or several states, for example, the worldwide Internet. cover an area up to several tens of square meters, and regional networks are networks that are located on the territory of a region or city.
However, the two main terms in the classification of networks are: WAN and LAN.
To connect to such networks, modems were used that worked under the control of specialized telecommunication programs, such as COMIT, PROCOM, BITCOM, MITEZ, etc. Managed by MS-DOS, they exchanged information with the computer to which the connection was established.
The construction of the global network itself is not difficult to describe. The global network consists of cells, which are local networks. Local networks, on the other hand, are made up of smaller networks and individual computers. It is this multi-level hierarchy that ensures the construction of the network. In addition, each device on the network must have its own IP address or unique identifier.
Nowadays, single computers that are part of global computer networks are used less and less. Basically, these are home PCs. For the most part, subscribers of networks are those computers that are included in local ones, therefore, most often, specialists are working out options on how best to ensure the interaction of several local area networks at once. At the same time, it is necessary to ensure that the remote computer has a connection with any computer included in the remote local network, or vice versa. The latter option is very relevant with an increase in the number of home and personal computers.
Now, switching centers are used as network equipment, which are specialized devices for X.25 networks from manufacturers Telenet, Ericsson, Siemens, Alcatel, etc., but for networks with TCP / IP, Decnis and Cisco routers are used. However, technology does not stand still, and it is likely that in the future we will see an even more efficient organization of the global network, which today has a huge impact on the lives of almost everyone.
A lot has been said. This is not surprising, given the fact that at present a huge number of electronic devices provide the ability to connect to it. These are not only computers, but also ATMs, smart home systems, communication devices and even TVs. In general, it is fundamentally impossible to give the entire list. In fact, if telephone networks allow people to communicate, then the global Internet makes it possible for electronic devices to exchange information.
It is necessary to distinguish between local networks, consisting of several computers in a relatively small area, and the Internet, covering the whole world.
The history of the emergence of the Internet began back in 1957, when the US Department of Defense, concerned about the problem of communication in a war with a possible enemy, proposed that the country's four leading universities develop a network for exchanging digital data between electronic computing devices. The result of their activities was the ARPANET, which appeared in September 1969 and linked these universities.
On October 29 of the same year, the first attempt at computer communication was made between the nodes in California and Stanford (six hundred and forty kilometers). At 10:30 pm, a stable connection was established, and this is considered the birth of the Internet (although, in fact, it was still the ARPANET network).
Then various programs for e-mail exchange begin to appear and are actively used. At the same time, for the first time, the concept of "mailing list" appears. Although ARPANET was the largest, computer networks existed in parallel with it, the operation of which was carried out on the basis of other technical and software solutions. It was obvious that a certain standard was needed that would allow them to interact with each other. So, since January 1983, ARPANET switched to using the TCP / IP protocol (instead of NCP). It is believed that from that moment the global Internet network began its victorious march across the Earth.
In 1984, the system that is still in use today was introduced. In the same year, another large network appears - NSFNet (American Science Foundation). Its peculiarity is that it consisted of several small networks, therefore it was more flexible in scaling than ARPANET. So, in just a year, the number of connected machines exceeded 10 thousand, which at that time was quite a lot. After that, the term "global Internet network" began to be used specifically for NSFNet.
In 1988, the real-time protocol IRC appeared, providing the ability to organize chats.
A year later, the HTML language and the corresponding protocol appeared, serving as the beginning of the creation of the World Wide Web.
In 1990, ARPANET disappeared, finally losing to NSFNet. Since 1991, all data on the World Wide Web has become available via the Internet. And after the creation of the Mosaic browser in 1993, the global Internet has become more and more popular and accessible every year.
The general principles of technical implementation are as follows: a certain provider company provides end users (computers) with access to information. All computers are connected to the servers of this company, and from there - to the requested addresses in the global network. Moreover, the address itself can be either directly the host server (on which the resource is located), or the destination computer. In other words, there is a system of branches, like blood vessels or even neural connections in the brain.
Now the development of the Internet is aimed at increasing the introduction of the IP protocol of the next version and optimizing the existing principles of work.
Let's try to figure out in this article what the Internet is and what it is eaten with! Nowadays, the Internet has become an integral part of our lives: entertainment and recreation, work and news, answers to questions and much more! The main value, probably, can be considered a 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 interconnected 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 network computers. – Wikipedia
How is the Internet organized?
As you understood from the introduction, the Internet is billions of computers interconnected, cables pass under the oceans under the water column, connecting the continents, and then they come to the user, but in a modified, simpler way.
The entire Internet connection is mostly built on digital IP addresses! All connections with any device on the network go through the protocols (http: , ftp:) it's like a language of communication between computers.
When you enter 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?
Internet It has a wide range of possibilities, I think you probably know half of it, and some of it you participated in! But the main thing is, of course, the transfer of information, at 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 possibilities are:
- Web - Surfing (web browsing)
- Manage remote computers (allows you to help or work on another computer)
- Communication (messaging, mail, etc.)
- Data exchange (any files
- Money transfer (work 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 the same computer is called the Site! Typically, Internet pages are textual information, but may contain any digital file.
WEB is the most popular Internet service, you don't notice when you talk about the Internet you mean WEB! Virtually the entire web as it is exists through hyperlinks that take you through the pages. You can also easily navigate by entering the address of a resource 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 the given address does not exist - correct the correctness of the set, BUT there are cases by typing the address you will be taken to a site with advertising or "poor quality" information. In such cases, immediately leave the page, 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, DOMAIN, that is, it is important to enter the correct name of the site, for examplew-d-x.en
After that, 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 The IP address, which is the actual address of the site. It is at this address that the browser (web browser) downloads the page. Domains were invented so that addresses were easy to remember and enter.
All transfers from a digital address to a clear alphabetic address are handled by special serversDNS (domainnameserver). One of the largestDNS servers is server centerGoogle.
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 are the possibilities of the global network, limited only by the Internet. Let's try to understand this issue in 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 with 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 unite individual computers or terminals located on a local network, regardless of their physical location. So what is it?
Indeed, this is a certain structure that is capable of ensuring the interaction of user terminals or even mobile devices, regardless of where they are located on the globe. What is most interesting, such structures are virtual concepts, since wired connections between all devices around the world cannot be established simply physically.
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 networks of both types.
The local network itself is designed to combine 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 respect 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 in principle (except for assigning an external identifier to each device, such as an IP address on the Internet, or a mobile phone number). The IPv4 protocol will soon exhaust its capabilities due to the limited number of assigned addresses, but in the sixth version, which replaces the fourth, such restrictions, if any, are very conditional.
Organization principles
The development of global networks began, as it is believed, from the moment when they tried to establish communication between computer devices via ARPANET. This network is fundamentally the progenitor of the modern Internet.
Only at the dawn of the implementation of such an idea, communication was carried out through cables, but over time, solutions for organizing computer interaction reached a new level. In simple terms, the structure is such that on the one hand there is a LAN router for egress, and on the other, a switch for communication with the required parts of the WAN.
Types of WANs
If we talk about what a global network is, it is impossible not to touch upon the issue of modern types of such computer structures.
Basically, several main classes are distinguished in the classification, among which any user knows such as:
- satellite networks;
- mobile networks;
- the Internet and its varieties.
How it works?
As it is already clear, access to the global network is provided by identifying the device, and communication is carried out through the use of special protocols.
For different networks and different operating systems, the protocols themselves may differ, 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 that access 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 person of the user himself. All this applies exclusively to computers or mobile devices.
The most famous global networks
In general, today it is considered to be the most popular networks such as the Internet and FidoNet. However, few people realize that the networks of mobile operators are also a kind of global structures that use GSM technology standards for communication between devices.
But what about 3G/4G? Here you need to clearly understand that these standards are used exclusively for accessing the Internet, and, in other words, for connecting one global network to another. And any global network is initially focused on high data transfer rates, which distinguishes it from the local structure. But today, the networks of mobile operators can equally be attributed to both local and global networks, since they combine 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 practically unlimited.
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 branched out. If earlier it was focused mainly on sending correspondence in the form of e-mail or visiting web pages, today its resources are such that users anywhere in the world can communicate with each other, say, via video chats in real time or on social networks, download 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 means 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? It is a tool that provides programmatic interaction at all levels and between any users.
But the advent of the World Wide Web, in a certain sense, has also given rise to many problems, since it is on the Internet that such a huge number of viruses, malicious codes and programs are spread today, which is difficult to imagine. Even the most advanced antivirus software developers do not have time to keep up with their appearance.
Of course, this is not all the possibilities that can be cited as an example. Bitcoin mining, which has recently been gaining momentum, can also be attributed to such tools. Here the technology is such that through the Internet it is possible to 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 certain sense, such programs can be called viruses or actions that fall under the jurisdiction of illegal access to someone else's information, however, it is precisely as a means of global networks that such opportunities cannot be discounted.
In addition, it is worth noting separately network operating systems that do not require installation on a hard drive, but can be loaded onto a computer terminal from a remote server, ensuring the full operation of any device. It is believed that such technologies are the most relevant today, since the protection system used for their structures and remote access is much higher than in stationary systems.
Brief conclusions
On the whole, 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 was not really the question. At least from the above material, one can understand what kind of structures they are, why they are needed and what basic capabilities they have.
Covering large areas and including a large number of computers.
GCNs serve to unite disparate networks so that users and computers, wherever they are, can interact with all other participants in the global network.
Some GCSs are built exclusively for private organizations, others are a means of communicating corporate LANs with the Internet or via the Internet with remote networks that are part of corporate ones. Most often, the GCS relies on leased lines, at one end of which the router is connected to the LAN, and at the other end, the switch communicates with the rest of the GCS. The main protocols used are TCP/IP , SONET /SDH , MPLS , ATM and Frame Relay . Previously, the X.25 protocol was widely used, which can rightfully be considered the progenitor of Frame Relay.
Description
Connects computers dispersed at a distance of hundreds and thousands of kilometers. Often existing low-quality communication lines are used. Lower than in local networks, data transfer rates (tens of kilobits per second) limit the range of services to file transfer, mainly not online, but in the background, using e-mail. For stable transmission of discrete data, more sophisticated methods and equipment are used than in local networks.
The difference between a global network and a local
Global networks differ from local networks in that they are designed for an unlimited number of subscribers and, as a rule, use not very high-quality communication channels and a relatively low transmission rate, and the exchange control mechanism cannot, in principle, be guaranteed fast.
In global networks, it is not the quality of communication that is much more important, but the very fact of its existence. True, at the moment it is no longer possible to draw a clear and unambiguous limit between local and global networks. Most local networks have access to the global network, but the nature of the transmitted information, the principles of exchange organization, the modes of access to resources within the local network, as a rule, are very different from those accepted in the global network. And although all computers on the local network in this case are also included in the global network, this does not negate the specifics of the local network. The ability to access the global network remains just one of the resources shared by users of the local network.
The largest GKS
Wikimedia Foundation. 2010 .
See what the "Global Computer Network" is in other dictionaries:
secure global computer network- Cryptographic protocol of the American company Netscape Communications, designed to protect information during its transmission over the global Internet. Topics information security EN … Technical Translator's Handbook
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The "LAN" request is redirected here; see also other meanings. Request "LAN" is redirected here; see also other meanings. Local area network (LAN, local area network, slang locale; English Local Area Network, LAN) ... ... Wikipedia
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Books
- Informatics Course of lectures, Fedotova E., Fedotov A.. The course of lectures on computer science includes consideration of the following topics: computer science and information technology (general provisions); PC device; software; OS Windows; applied…
