What is wifi and how to use it. Selecting a Wi-Fi network standard. Basic Wi-Fi Standards

Internet access points using Wi-Fi are now available in almost every home, as well as in bars, restaurants, even recreation parks and other public places, since WiFi is universal method, characterized by convenience, decent speed and security. The system has already become available today smart House", which allows you to manage all electronic devices in the house (computer, TV, etc.) from any room using a single remote control. And every year everyone is introducing it more apartments

How WiFi works

Wi-Fi works a little differently than a wired network. Internet access source in in this case is an Ethernet packet data transmission technology. Access to it is provided through a fixed connection. To use the conveniences of the World Wide Web, you need to have the so-called. router, or router, which will transmit information through channels of a certain frequency.

In order not to confuse the networks, each transmitted at its own frequency, using desktop computer, to which the router is connected, each network is assigned its own name. The network can be public, meaning anyone can connect to it if they have a suitable device and are within the coverage area, or it can be protected with a password that the user sets. Entering a password, as a rule, is only necessary when connecting to the network for the first time, after which it is saved in the device database.

The role of a Wi-Fi distribution point can be played not only by a router, but also by a smartphone that contains a special module. Teach your router to “distribute” wireless Internet you can do it yourself, using the instructions that are found in abundance on the Internet.

Where is Wi-Fi used?

Any private user who has purchased and configured the Wi-Fi router. Equip Wi-Fi module Any modern electronics, be it a computer, TV or kettle, after which, if you have a router and a remote control, it can be controlled remotely, expanding its capabilities.

In public institutions, Wi-Fi is also used almost everywhere. You can connect to the Internet using your laptop, tablet PC or smartphone in almost any restaurant, bar, cafe, shopping center, or hotel. WiFi access points today also work in many libraries, public recreation centers and train stations. This makes the user's stay in public place more comfortable and lasting.

Legal entities also use advantages Wi-Fi connections for your own purposes. By establishing a powerful access point to demons wired network with extended coverage area, can be supplemented fixed connection To World Wide Web or even replace it altogether. And the more company employees have laptops and other portable technical devices, the more expedient it is to use Wi-Fi.

However, the applications of Wi-Fi are not limited to the above-mentioned places. Today you can use a wireless Internet connection both on trams and in medical institutions, and even on an airplane.

Network standards

The Institute of Electrical and Electronics Engineers, or IEEE, has currently developed the following Wi-Fi network standards:

• IEEE 802.11– basic standard with low data transfer rate;
• IEEE 802.11b allows the possible transmission of information at a frequency of 2.4 GHz at a speed of 11 Mbit/s;
• IEEE 802.11a– standard operating in frequency spectrum 5 GHz with max. speed 54 Mbit/s;
• IEEE 802.11g similar to the previous standard, but compatible with IEEE 802.11b and uses the 2.4 GHz frequency range;
• IEEE 802.11n– the best standard for commercial use, operating in the 20 MHz and 40 MHz spectrum and supporting up to 4 transmitters ( maximum speed– 600 Mbit/s, one antenna – 150 Mbit/s);
• IEEE 802.11ac– the latest standard that operates at frequencies of 2.4 GHz and 5 GHz, providing maximum possible speed transmission of information for today.

These are the main standards, in addition to which there are others, additional ones (from d to w). Each of them serves its own purpose. For example, 802.11s is used to implement wireless mesh networks, and 802.11n is used to implement wireless local area networks (WLANs).

Wi-Fi security modes

IN this moment There are three security modes for wireless networks with varying degrees of reliability:

• outdated today WEP (Wired Equivalent Privacy), which provides a minimum level of protection;
• WPA (Wi-Fi Protected Access) provides more reliable protection data and is divided into Personal (for private use) and Enterprise (for corporate use), providing a multi-stage information security system and using the RADIUS protocol;
• WPA2– an improved version of WPA that allows both private and corporate users to work.

When connecting to free Wi-Fi somewhere in a cafe or other public place, make sure that the network uses WPA2 security mode (in extreme cases, WPA). Best option– WPA2-PSK with AES encryption.

(English: Wireless Fidelity - “wireless precision”) - a standard for Wireless LAN equipment.

Developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards, "Wi-Fi" - trademark"Wi-Fi Alliance". The technology was called Wireless-Fidelity (literally “wireless precision”) by analogy with Hi-Fi.

Installation of Wireless LAN was recommended where deployment of a cable system was impossible or economically impractical. Nowadays, many organizations use Wi-Fi, since under certain conditions the network speed already exceeds 100 Mbit/s. Users can move between access points throughout the Wi-Fi network coverage area.

Mobile devices (PDAs, smartphones and laptops) equipped with client Wi-Fi transceivers can connect to a local network and access the Internet through access points or hotspots.

Story

Wi-Fi was created in 1991 by NCR Corporation/AT&T (later Lucent and Agere Systems) in Nieuwegein, the Netherlands. Products originally intended for point-of-sale systems were introduced to the market under the WaveLAN brand and provided data transfer rates of 1 to 2 Mbit/s. Vic Hayes, the creator of Wi-Fi, has been called the "father of Wi-Fi" and was on the team that helped develop standards such as IEEE 802.11b, 802.11a and 802.11g. In 2003, Vic left Agere Systems. Agere Systems was unable to compete on equal terms in difficult market conditions, despite the fact that its products occupied the niche of cheap Wi-Fi solutions. Agere's 802.11abg all-in-one chipset (codename: WARP) sold poorly, and Agere Systems decided to exit the Wi-Fi market at the end of 2004.

Principle of operation

Typically, a Wi-Fi network diagram contains at least one access point and at least one client. It is also possible to connect two clients in point-to-point mode, when the access point is not used, and the clients are connected via network adapters"directly". The access point transmits its network identifier (SSID) using special signaling packets at a speed of 0.1 Mbit/s every 100 ms. So 0.1 Mbps is the lowest data transfer speed for Wi-Fi. Knowing the network SSID, the client can find out whether a connection to a given access point is possible. When two access points with identical SSIDs are within range, the receiver can choose between them based on signal strength data. The Wi-Fi standard gives the client complete freedom in choosing the criteria for the connection. More details about the operating principle can be found in the official text of the standard.

Benefits of Wi-Fi

* Allows you to deploy a network without laying cables, can reduce the cost of network deployment and expansion. Places where cable cannot be installed, such as outdoors and buildings of historical value, can be served by wireless networks.

* Wi-Fi devices are widely available in the market. A devices different manufacturers can interact on basic level services.

* Wi-Fi is a set of global standards. Unlike cell phones, Wi-Fi equipment can work in different countries Worldwide.

Disadvantages of Wi-Fi

*Frequency range and operating restrictions vary from country to country; many European countries allow two additional channels that are prohibited in the United States; Japan has another channel at the top of the band, and other countries, such as Spain, prohibit the use of low-band channels. Moreover, some countries, such as Italy, require registration of all Wi-Fi networks operating outdoors or require registration of the Wi-Fi operator.

* High energy consumption compared to other standards, which reduces battery life and increases the temperature of the device.

* The most popular encryption standard, WEP, can be relatively easily broken[source?] even with correct configuration(due to the weak stability of the algorithm). Although newer devices support the more advanced WPA data encryption protocol, many older access points do not support it and require replacement. The adoption of the IEEE 802.11i (WPA2) standard in June 2004 made a more secure scheme available in new equipment. Both schemes require a stronger password than those typically assigned by users. Many organizations use additional encryption (such as a VPN) to protect against intrusion.

* Wi-Fi has a limited range. Typical home Wi-Fi router 802.11b or 802.11g standard has a range of 45 m indoors and 90 m outdoors. A microwave or mirror placed between Wi-Fi devices will weaken the signal. The distance also depends on the frequency.

* Overlapping signals from a closed or encrypted access point and an open access point operating on the same or adjacent channels may interfere with access to the open access point. This problem may occur when there is a high density of access points, such as in large apartment buildings, where many residents put their points Wi-Fi access.

* Incomplete compatibility between devices from different manufacturers or non-compliance with the standard may result in limited connection capabilities or reduced speed.

* Reduced network performance during rain.

* Equipment overload when transmitting small data packets due to the attachment of a large amount of service information.

* Low suitability for applications using real-time media streams (for example, the RTP protocol used in IP telephony): the quality of the media stream is unpredictable due to possible high losses during data transmission caused by a number of factors uncontrollable by the user (atmospheric interference, landscape and others, in particular those listed above). Despite this drawback, a lot of VoIP equipment based on 802.11b\g devices is produced, which is also aimed at the corporate segment: however, in most cases, the documentation for such devices contains a disclaimer stating that the quality of communication is determined by the stability and quality of the radio channel.

Commercial Wi-Fi Use

Commercial access to Wi-Fi-based services is available in places such as Internet cafes, airports and cafes around the world (usually these places are called Wi-Fi cafes), but their coverage can be considered spotty compared to cellular networks:

* Ozone and OzoneParis In France. In September 2003, Ozone began rolling out the OzoneParis network through The City of Lights. Final goal- creation of a centralized Wi-Fi network that completely covers Paris. The core principle of the Ozone Pervasive Network is that it is a national network.

* WiSE Technologies provides commercial access to airports, universities, and independent cafes throughout the United States.

* T-Mobile operates hotspots for Starbucks in the US and UK, as well as more than 7,500 hotspots in Germany.

*Pacific Century Cyberworks provides access to Pacific Coffee stores in Hong Kong.

* Columbia Rural Electric Association is trying to deploy a 2.4 GHz Wi-Fi network in a 9,500 km² area located between Walla Walla and Columbia counties in Washington state and Umatilla, Oregon; Add to list of others large networks in the US also includes: Boingo, Wayport and iPass.

* Sify, an Indian Internet service provider, has installed 120 hotspots in Bangalore, in hotels, galleries and government offices.

* Vex has a large network of hotspots located throughout Brazil. Telefónica Speedy WiFi has begun to provide its services on a new growing network that has expanded throughout the state of São Paulo.

* BT Openzone owns many of the UK's McDonald's hotspots and has a roaming agreement with T-Mobile UK and ReadyToSurf. Their customers also have access to The Cloud's hotspots.

* Netstop provides access in New Zealand.

* Golden Telecom supports the world's largest urban Wi-Fi network in Moscow, and also provides its communication channels for the implementation of the Yandex project. Wi-Fi (). Access channels to the wired network are provided by the largest Moscow provider Corbina Telecom

* EarthLink plans to fully connect Philadelphia (USA) to the wireless Internet in the third quarter of 2007. It will be the first metropolitan area in the United States to be fully covered by Wi-Fi. The cost will be between 20-22 dollars per month with a connection speed of 1 Mbit/sec. For low-income residents of Philadelphia, the cost will be $12-$15 per month. Currently, the city center and surrounding areas are already connected. The remaining areas will be connected as transmitters are installed.

Wireless technologies in industry

For industrial use, Wi-Fi technologies are currently offered by a limited number of suppliers. Thus, Siemens Automation & Drives offers Wi-Fi solutions for its SIMATIC controllers in accordance with the IEEE 802.11g standard in the free 2.4 GHz ISM band and providing a maximum transmission speed of 11 Mbit/s. These technologies are mainly used to control moving objects and in warehouse logistics, as well as in cases where for some reason it is impossible to lay wired Ethernet networks.

Wi-Fi and cell phones

Some believe that Wi-Fi and similar technologies could eventually replace cellular networks such as GSM. Barriers to this development in the near future include the lack of roaming and authentication capabilities (see 802.1x, SIM cards and RADIUS), limited frequency spectrum and severely limited Wi-Fi range. It would be more correct to compare Wi-Fi with other cellular network standards, such as UMTS or CDMA.

However, Wi-Fi is ideal for using VoIP in enterprise networks or SOHO environments. The first samples of equipment were available in the early 90s, but did not go into commercial use until 2005. Then Zyxel, UT Starcomm, Samsung, Hitachi and many others introduced VoIP Wi-Fi phones to the market at “reasonable” prices. In 2005, ADSL ISP providers began providing VoIP services to their customers (for example, the Dutch ISP XS4All). When VoIP calls became very cheap, and often free, providers capable of providing VoIP services were able to open new market- VoIP services. GSM phones with integrated support for Wi-Fi and VoIP capabilities have begun to come to market and have the potential to replace corded phones.

Direct comparisons between Wi-Fi and cellular networks are not practical at this time. Wi-Fi-only phones have very limited range, making such networks very expensive to deploy. However, the deployment of such networks may be the best solution for local use, for example, in corporate networks. However, devices that support multiple standards can capture a significant market share.

International projects

Another business model is to connect existing networks into new ones. The idea is that users will share their frequency range through personal wireless routers, equipped with special software. For example, FON is a Spanish company created in November 2005. It intends to become the largest hotspot network in the world by the end of 2006 with 30,000 access points. Users are divided into three categories:

* linus - highlighting free Internet access,

* bills - selling their frequency range,

* aliens - using access through bills.

Thus, the system is similar to peer-to-peer services. Even though FON receives financial support From companies like Google and Skype, it will only be clear over time whether this idea will actually work.

There are currently three main problems with this service. The first is that to move a project from initial stage Basically, more attention from the public and the media is required. You must also take into account the fact that providing access to your Internet channel to others may be limited by your agreement with your Internet provider. Therefore, Internet providers will try to protect their interests. The same will most likely be done by record companies that oppose the free distribution of MP3s. And thirdly, software FON is still in beta testing and we can only wait for the security issue to be resolved.

Wi-Fi in the gaming industry

* Wi-Fi is compatible with game consoles and PDAs and allows you to play online games through any access point.

* All seventh generation game consoles support IEEE 802.11g Wi-Fi standards.

* Sony PSP has wireless network support, which is activated with the press of a button, for connecting to Wi-Fi hotspots or other wireless connections.

Non-commercial use of Wi-Fi

While commercial services try to leverage existing business models for Wi-Fi, many groups, communities, cities, and individuals are building free Wi-Fi networks, often using a shared peering agreement to allow the networks to communicate freely with each other.

Many municipalities are teaming up with local communities to expand free Wi-Fi networks. Some groups build their Wi-Fi networks entirely based on volunteers and donations.

To get more detailed information See the section on shared wireless networks, where you can also find a list of free Wi-Fi networks located around the world (see also Free Wi-Fi hotspots in Moscow).

OLSR (en) is one of the protocols used to create free networks. Some networks use static routing, others rely entirely on OSPF. In Israel, the WiPeer protocol is being developed to create free P2P networks based on Wi-Fi.

Wireless Leiden has developed its own routing software called LVrouteD to connect Wi-Fi networks built on a completely wireless basis. Most networks are built on software with open source, or publish their scheme under an open license. See, for example, “WiFi Liberator” (turns any laptop with MAC OS X installed and a Wi-Fi module into an open Wi-Fi network node).

Some small countries and municipalities already provide free access to Wi-Fi hotspots and Internet access via Wi-Fi at their place of residence for everyone. For example, the Kingdom of Tonga or Estonia, which have a large number of free Wi-Fi hotspots throughout the country. In Paris, OzoneParis provides free, unlimited Internet access to everyone who contributes to the development of the Pervasive Network by providing the roof of their home to install a Wi-Fi network. Unwire Jerusalem is a project to install free Wi-Fi access points in large shopping centers Jerusalem. Many universities provide free access to the Internet via Wi-Fi for their students, visitors and anyone on campus.

Some businesses, such as Panera Bread, provide free Wi-Fi access regular customers. McDonald's Corporation also provides access to Wi-Fi under the "McInternet" brand. This service was launched at a restaurant in Oak Brook, Illinois; it is also available in many restaurants in London.

However, there is a third subcategory of networks created by communities and organizations such as universities, where free access is provided to members of the community, but access to those outside the community is provided on a paid basis. An example of such a service is the Sparknet network in Finland. Sparknet also supports OpenSparknet, a project where people can make their own access points part of the Sparknet network and benefit from it.

Recently, commercial Wi-Fi providers have been building free Wi-Fi hotspots and hot zones. They believe that free Wi-Fi access will attract new customers and investments will return.

Russian Wi-Fi Alliance

* On October 5, 2008, the Russian Wi-Fi Alliance was created, uniting all Wi-Fi providers who provide this service free of charge. The main difference of the project is the combination of only free Wi-Fi hotspots.

* All providers and operators that are members of the Wi-Fi Alliance mark their zones with a special “Free Wi-Fi here” sticker.

* Information on access points in different cities can be found on the official website

Wi-Fi and software

* BSD family operating systems (FreeBSD, NetBSD, OpenBSD) can work with most adapters since 1998. Drivers for Atheros, Prism, Harris/Intersil and Aironet chips (from the respective manufacturers Wi-Fi devices) are usually included in BSD operating systems since version 3. Darwin and Mac OS X, although overlapping with FreeBSD, have their own, unique implementation. In OpenBSD 3.7, more drivers were included for wireless chips, including RealTek RTL8180L, Ralink RT25x0, Atmel AT76C50x, and Intel 2100 and 2200BG/2225BG/2915ABG. Thanks to this, it was partially possible to solve the problem of the lack of open drivers for wireless chips for OpenBSD. It is possible that some drivers implemented for other BSD systems could be ported if they have not already been created. NDIwrapper is also available for FreeBSD.

* GNU/Linux: Since version 2.6, support for some Wi-Fi devices has appeared directly in the Linux kernel. Support for Orinoco, Prism, Aironet, Atmel, Ralink chips is included in the main kernel branch; ADMtek and Realtek RTL8180L chips are supported by both closed manufacturers' drivers and open ones written by the community. Intel Calexico is supported by open source drivers available on SourceForge.net. Atheros is supported through open source projects. Supporting others wireless devices available using the open-source NDISwrapper driver, which allows Linux systems running on Intel x86-based computers to "wrap" the manufacturer's Microsoft Windows drivers for direct use. There is at least one known commercial implementation of this idea. The FSF has created a list of recommended adapters, more information can be found on the Linux wireless website.

* There are quite a large number of Linux-based firmware for wireless routers, distributed under the GNU GPL license. These include the so-called “firmware from Oleg”, FreeWRT, OpenWRT, X-WRT, DD-WRT, etc. As a rule, they support many more functions than the original firmware. Necessary services can be easily added by installing the appropriate packages. The list of supported equipment is constantly growing.

* In the Microsoft Windows family of operating systems, Wi-Fi support is provided, depending on the version, either through drivers, the quality of which depends on the vendor, or through Windows itself.

o Earlier versions of Windows, such as Windows 2000 and earlier, do not have built-in configuration and management tools, and this varies by hardware vendor.

o Microsoft Windows XP supports configuration of wireless devices. Although the initial version included fairly weak support, it improved significantly with the release of Service Pack 2, and with the release of Service Pack 3, WPA2 support was added.

o Microsoft Windows Vista includes improved Wi-Fi support compared to Windows XP.

o Microsoft Windows 7 supports all modern wireless devices and encryption protocols at the time of its release.

Legal status

The legal status of Wi-Fi varies from country to country. In the US, the 2.5 GHz band can be used without a license, provided the power does not exceed a certain amount and such use does not interfere with those who are licensed.

In Russia, using Wi-Fi without permission to use frequencies from State Commission over radio frequencies (GKRF) is possible for organizing a network inside buildings, closed storage facilities and production areas. To legally use an off-site wireless Wi-Fi network (for example, a radio channel between two neighboring houses), you must obtain permission to use frequencies. There is a simplified procedure for issuing permits for the use of radio frequencies in the band 2400-2483.5 MHz (802.11b and 802.11g standards); to obtain such a permit, a private decision of the SCRF is not required. To use radio frequencies in other bands, in particular 5 GHz (802.11a standard), you must first obtain a private solution from SCRF. In 2007, the situation changed with the release of the document: “Resolution No. 476 of July 25, 2007 On amendments to the Decree of the Government of the Russian Federation of October 12, 2004 No. 539 “On the procedure for registering radio-electronic equipment and high-frequency devices.” The resolution is briefly stated here : , where the sixteenth paragraph excludes from the list of equipment subject to registration: User (terminal) radio access equipment (wireless access) in the radio frequency band 2400-2483.5 MHz with the radiation power of transmitting devices up to 100 mW inclusive But, manipulating the implicit definition of “terminal equipment. "(since the network concentrator of the end backbone point can also be considered terminal equipment) some representatives of the regional SCRF, being at the same time communication service providers in individual regions of the Russian Federation, are turning the changes to Resolution No. 476 in a direction convenient for themselves.[source?]

For violation of the procedure for the use of radio-electronic means, liability is provided under Articles 13.3 and 13.4 of the Code of the Russian Federation on Administrative Offenses (CAO RF). Thus, in July 2006, several companies in Rostov-on-Don were fined for operating open Wi-Fi networks (hot spots). Recently federal Service for supervision in the field of mass communications, communications and cultural heritage protection has issued a new clarification on the use and registration of all devices using Wi-Fi. Later it turned out that there is a commentary by Rossvyazohrankultura, which partially refutes the misunderstandings developed by online media.

On the territory of Ukraine, using Wi-Fi without permission from the UDCR (Ukrainian State Radio Frequency Center) is possible only if you use an access point with a standard omnidirectional antenna (<6 Дб, мощность сигнала ≤ 100 мВт на 2.4 ГГц и ≤ 200 мВт на 5 ГГц) для внутренних (использование внутри помещения) потребностей организации (Решение Национальной комиссии по регулированию связи Украины № 914 от 2007.09.06) В случае сигнала большей мощности либо предоставления услуг доступа в Интернет, либо к каким-либо ресурсам, необходимо регистрировать передатчик и получить лицензию УДЦР.

(c) Material from Wikipedia - the free encyclopedia

At the beginning of the development of the Internet, the network connection was carried out using a network cable, which had to be installed indoors in such a way that it would not interfere. They secured it and hid it as best they could. Old computer furniture still has holes for cable routing.

When wireless technologies and Wi-Fi networks became popular, the need to run network cables and hide them disappeared. Wireless technology allows you to receive the Internet “over the air” if you have a router (access point). The Internet began to develop in 1991, and closer to 2010 it had already become especially popular.

What is Wi-Fi

This is a modern standard for receiving and transmitting data from one device to another. In this case, the devices must be equipped with radio modules. Such Wi-Fi modules are part of many electronic devices and equipment. At first they were included only in a set of tablets, laptops, and smartphones. But now they can be found in cameras, printers, washing machines, and even multicookers.

Principle of operation

To access Wi-Fi, you must have an access point. Today, such a point is mainly a router. This is a small plastic box, on the body of which there are several sockets for connecting the Internet via wire. The router itself is connected to the Internet via a network wire called twisted pair. Through the antenna, the access point distributes information from the Internet to the Wi-Fi network, through which various devices with a Wi-Fi receiver receive this data.

A laptop, tablet or smartphone can work instead of a router. They must also have a mobile internet connection via a SIM card. These devices have the same data exchange principle as a router.

The method of connecting the Internet to the access point does not matter. Access points are divided into private and public. The former are used only for use by the owners themselves. The latter provide Internet access for money or free of charge to a large number of users.

Public hot spots are most often found in public places. It is easy to connect to such networks while being on the territory of this point or near it. Some places require you to log in, but you are offered a password and login if you use the paid services of this establishment.

In many cities, their entire territory is completely covered by a Wi-Fi network. To connect to it, you need to pay for a subscription, which is not expensive. Consumers are provided with both commercial networks and free access. Such networks are built by municipalities and private individuals. Small networks for residential buildings, public institutions become larger over time, use peering agreements to interact freely with each other, work on voluntary assistance and donations from other organizations.

City authorities often sponsor similar projects. For example, in France, some cities provide unlimited Internet access to those who give permission to use the roof of the house to install a Wi-Fi antenna. Many universities in the West allow online access to students and visitors. The number of hotspots (public points) is growing steadily.

Wi-Fi standards

IEEE 802.11– protocols for low data rates, the main standard.

IEEE 802.11a– is incompatible with 802.11b, for high speeds, uses 5 GHz channels. Capable of transmitting data up to 54 Mbit/s.

IEEE 802.11b– standard for fast speeds, channel frequency 2.4 GHz, throughput up to 11 Mbit/s.

IEEE 802.11g– speed equivalent to standard 11a, channel frequency 2.4 GHz, compatible with 11b, bandwidth up to 54 Mbit/s.

IEEE 802.11n– the most advanced commercial standard, channel frequencies 2.4 and 5 GHz, can work in conjunction with 11b, 11g, 11a. The highest operating speed is 300 Mbit/s.

To understand in more detail the operation of various wireless communication standards, consider the information in the table.

Using a Wi-Fi network

The main purpose of wireless communications in everyday life is to access the Internet to visit websites, communicate online, and download files. There is no need for wires. Over time, the spread of access points throughout cities is progressing. In the future, it will be possible to use the Internet using a Wi-Fi network in any city without restrictions.

Such modules are used to create a network within a limited area between several devices. Many companies have already developed mobile applications for mobile gadgets that make it possible to exchange information via Wi-Fi networks, but without connecting to the Internet. This application organizes a data encryption tunnel through which information will be transmitted to the other party.

Information exchange is carried out much faster (several tens of times) than via Bluetooth as we know it. The smartphone can also act as a game joystick in connection with a game console or computer, or perform the functions of a TV remote control operating via Wi-Fi.

How to use a Wi-Fi network

First you need to buy a router. You must insert the power cord into the yellow or white socket and configure it according to the included instructions.

On receiving devices with a Wi-Fi module, turn it on, search for the required network and connect. The more devices connected to one router, the lower the data transfer speed will be, since the speed is equally divided among all devices.

The Wi-Fi module looks like a regular flash drive; the connection is made via a USB interface. It has a low cost. On your mobile device, you can enable an access point that will act as a router. When a smartphone distributes the Internet via an access point, it is not recommended to overload the processor on it, that is, it is not advisable to watch videos or download files, since the speed is divided between the connected and the distribution device on a residual basis.

Wi-Fi technology makes it possible to access the Internet without a cable. The source of such a wireless network can be any device that has a Wi-Fi radio module. The propagation radius depends on the antenna. Using Wi-Fi, groups of devices can be created, and you can also simply transfer files.

AdvantagesWi— Fi

• No wiring required. Due to this, savings are achieved on cable laying, wiring, and time is also saved.
• Unlimited expansion of the network, with an increase in the number of consumers and network points.
• There is no need to damage the surfaces of walls and ceilings for laying cables.
• Globally compatible. This is a group of standards that works on devices manufactured in different countries.

FlawsWi— Fi

• In neighboring countries, the use of a Wi-Fi network without permission is allowed to create a network in premises, warehouses, and production. To connect two neighboring houses with a common radio channel, an application to the supervisory authority is required.
• Legal aspect. Different countries have different attitudes towards the use of Wi-Fi range transmitters. Some states require all networks to be registered if they operate on premises. Others limit transmitter power and certain frequencies.
• Communication stability. Routers installed at home, of common standards, distribute a signal over a distance of 50 meters inside buildings, and 90 meters outside the room. Many electronic devices and weather factors reduce the signal level. The distance range depends on the frequency of operation and other parameters.
• Interference. In cities, there is a significant density of router installation points, so problems often arise connecting to a point if there is another point nearby that operates at the same frequency with encryption.
• Manufacturing parameters. It often happens that manufacturers do not adhere to certain device manufacturing standards, so access points may have unstable operation, and the speed differs from the declared one.
• Electricity consumption. A sufficiently large energy consumption, which reduces the charge of batteries and accumulators, increases the heating of the equipment.
• Safety. Data encryption using the WEP standard is unreliable and easy to crack. The WPA protocol, which is more reliable, is not supported by access points on older equipment. The WPA2 protocol is considered the most reliable today.
• Limitation of functions. During the transmission of small packets of information, a lot of official information is attached to them. This makes the connection quality worse. Therefore, it is not recommended to use Wi-Fi networks to organize IP telephony using the RTP protocol, since there is no guarantee of communication quality.

Features of Wi-Fi and Wi MAX

Wi-Fi network technology was primarily created for organizations to move away from wired communications. However, this wireless technology is now gaining popularity in the private sector. The types of wireless connections Wi-Fi and Wi MAX are related in the tasks they perform, but they solve different problems.

Wi MAX devices have special digital communication certificates. Complete protection of data streams is achieved. Based on Wi MAX, private confidential networks are formed, which make it possible to create secure corridors. Wi MAX transmits the necessary information, despite the weather, buildings and other obstacles.

This type of communication is also used for high quality video communication. We can highlight its main advantages, consisting of reliability, mobility, and high speed.

The router is a small adapter that consists of a housing, a network adapter and an antenna. Some modern devices have a built-in antenna. The device consists of a housing and a board, which is responsible for converting a wired signal into a wireless one. The router can also act as a splitter for a wired connection (router). Thus, several computers can be connected to the router (up to 4 on average) and they can all use one wired Internet connection. The most expensive and advanced models of routers also support USB technologies for the ability to work with data storage devices and convert signals from USB 3G modems, which can be useful in an office environment. Some routers can be used as file servers to store and share files over an Internet connection.

Router standards

Routers differ in the number of supported standards and the functions they implement. Today, most modern devices support the 802.11n standard, which is the most advanced and fastest to date. However, there are still models that work in the already outdated 802.11b and 802.11g networks, which, unlike 802.11n, have a lower data transfer rate and radio signal coverage area.

Price

You can purchase a router at any computer store or electronics supermarket. Try to buy devices from well-known network equipment manufacturers (for example, D-Link, TP Link, ASUS, Zyxel, etc.). The starting price for an ordinary router can start from $15 for the simplest models, which are quite suitable for home use or use in a small office. Depending on the requirements for the device, its cost will also increase. As a rule, the key characteristic when buying a router is the coverage area, which is determined by the presence of amplifiers in the antenna and the number of additional antennas that will allow for wider signal broadcasting. Some devices have the ability to work in VPN client mode.

The speed of modern routers, under ideal conditions, cannot exceed 600 Mbit/s, however, in the operating conditions of modern wired networks, the use of routers that provide speeds above 150 Mbit/s is justified, because most often speeds of 600 Mbit/s cannot be achieved due to limitations of both radio signals and wired networks of modern Russian providers.

Wi-Fi is a new technology that has replaced the outdated and rather boring data transmission via wires.

By providing signals via radio, it allows you to forget about problems such as the need to lay cables, which must be hidden in baseboards and protected from breaks.

It should be noted that Wi-Fi is by far the most promising technology widely used in the field of computer communications.

The term Wi-Fi itself is a common abbreviation. Its decoding sounds like “Wireless Fidelity”, which translated from English means “Wireless Reliability”. The technology was created to service cash register systems (at that time the information transfer speed when using them was only 2 Mbit/s). There are three Wi-Fi protocol standards:

IEEE 802.11a
IEEE 802.11b
IEEE 802.11g

They differ from each other in the speed of signal transmission and the distance over which data is transmitted. When talking about Wi-Fi, they usually mean the IEEE 802.11b standard. It is characterized by a hundred-meter distance and a speed of 11 Mbit/s.

As already mentioned, Wi-Fi is designed for wireless data transfer. A standard network organized using it is formed by an access point and a client machine. The presence of one point and one user is required (there can be several clients). The access point performs an additional function - a signal transmitter and receiver. If you wish, you can forget about it and connect two clients directly using network adapters.

The access point also has its own identifier - SSID. It is transmitted at intervals of one hundred milliseconds in signaling packets. The lowest speed reaches 0.1 Mbit/s. If the client knows the network identifier, he can clarify whether he has the ability to connect specifically to his access point.

If the user is within the simultaneous range of several points with the same identifiers, he is able to connect to the point that has the best signal level.

Wi-Fi routers that are installed in homes are small devices that come complete with a hardware unit, an antenna (if there is a Wi-Fi function), a patch cord and a power supply. There must be an outlet in the place where the router will be located, since it operates from the electrical network.


Thanks to the router, you can create a home network of four computers at once using a cable, and another five to ten devices via Wi-Fi. If the router is equipped with a USB port, you can connect a flash drive/hard drive to it. Then it will be able to perform the functions of a torrent client, print or file server. Modern models are even equipped with support for 3G modems.

A home/office network created through a router is a combination of all personal computers into one local network. Cheap routers most often have four ports. This means that only four devices can be connected to them via cable.

Setting up a Wi-Fi router is quite simple, but then situations often arise when the Internet speed becomes very low and the connection disappears. The reason for this situation is that other neighboring access points are using the same channel. This creates interference and causes channel overload.

You can fix the problem by changing the settings. The fact is that most Internet users leave the “auto” value, which is set in the default router options. You can try to find free channels at random, but it is much wiser and more effective to conduct a competent search.

The easiest way to determine channels is to use a special program, for example, inSSIDer. Such utilities scan all networks and prepare special graphs of their distribution across channels. You can understand the meaning of the information received by using the description of the program being used. Usually those numbers over which the curve does not pass are free.

When the available channels that can provide an uninterrupted Wi-Fi connection are identified, you need to change the settings. It is important to take into account that the most effective range will be the one that is furthest away from the wireless signals on the graph. Then you need to go to the router settings, specify the optimal free channel and confirm the changes.

Despite the fact that the electromagnetic radiation coming from wireless transmitters is much lower than permitted, talk about the dangers of the technology does not stop. Scientists claim that she, whose body is at the stage of formation, and therefore is more susceptible to the influence of radiation than in adults.


Researchers also note that cracks form on tree trunks growing directly near powerful Wi-Fi sources, from which sap begins to leak. This also negatively characterizes a wireless Internet connection.

However, you should not blindly believe in all the data. Radiation from cell phones and microwave ovens has been proven to be more dangerous, so it's not as bad as you might think.