What is wi fi function. Understanding what Wi-Fi is - how it differs from Ethernet. How Wi-Fi works

Few people are worried about exploring the capabilities of their Wi-Fi router. There is internet, and okay. In fact, a good Wi-Fi router can do a lot of cool things. And in order to use all the possibilities, you do not need to have special knowledge, download alternative firmware and study hundreds of pages on forums. How it works - we will showusing the example of a router that can be bought for 2,500–2,700 rubles.

1. Connect your network to your neighbor's Wi-Fi. Or anyone else

Let's say a signal from a nearby cafe finishes you. Or, out of the kindness of his soul, a neighbor gave you a password for his Wi-Fi. Instead of connecting to the network from a smartphone, tablet or computer, connect to it through a router, and from the router use free internet... This function is called "" (WISP), and it has several advantages:

1. Better signal... If on a smartphone the wireless grid shows one or two stripes and works somehow, then from the router the same grid will give its full speed, and the connection will be much more stable.
2. Safely... You never know how security is going on an unfamiliar Wi-Fi network. When connecting to someone else's Wi-Fi through a router, you hide behind the built-in security means and do not shine on your devices and their contents in someone else's network.
3. Backup internet that connects automatically... If something suddenly breaks with your main provider, the router will automatically switch to the backup channel, and you most likely will not even notice it and will be able to continue using the Internet.
4. Backup internet from smartphone... Often, in case of problems with the Internet, we use a smartphone as an access point. The signal from him is weak and hits close. Create an access point on your smartphone, connect to the router as a "wireless provider", and you will get a good stable connection on all of their devices.

2. Use multiple providers on one router

This feature is called Multi WAN. It allows you to connect as many providers as there are ports on your router, and additionally add a USB modem.

Let's say you have an Internet connection from two providers at once. One is the main one, the second is the reserve one with the cheapest tariff. It is a good practice to stay online even if something is wrong with the main provider.

In order not to swap cables every time, not to reconfigure a router or computer, and not to do other time-consuming and energy-consuming things, just plug both cables into the router. The main one - to the standard port (it is usually of a different color), and the backup one - to any other. Configure the router once, and in the future everything will work and switch automatically.

3. Share the Internet from a USB modem through a router

This is possible if the router has a USB port, and you have a USB modem from a cellular operator, with which you can access the Network from a laptop from anywhere.

Connect the modem to the USB port of the router and execute quick setup on . You now have a backup Mobile Internet, which will be turned on automatically when problems arise with the main provider.

This life hack will allow you to use the Wi-Fi network not only at the dacha, where there is no fixed Internet, but also during the trip. On the Internet, you can find an adapter adapter to power the router from the cigarette lighter in the car. Connect a USB modem to the router, and all your passengers will be able to use the Internet while traveling - if, of course, there is a cellular signal.

If you have an external HDD, connect it to your router via USB.

Activate the ability to download torrents in the router settings.

You can remotely launch and manage downloads via the My.Keenetic Android application.

Downloading and distributing torrents through a router takes place without the participation of a computer. By default, upload and download speeds are set so as not to clog the entire channel. You can change the speed in the settings. You won't get more than 5 MB / s from the budget Keenetic Omni, but the Internet will not slow down when loading.

The router can not only download, but also broadcast video to the TV via DLNA, and in the torrent settings, you can select a sequential download of the torrent to start watching the movie before the download is complete.

5. Access your router and home devices from anywhere

A free proprietary KeenDNS service is available for all "kineticists", replacing any other DDNS services (such as No-IP and DynDNS) in a situation where you have a white but dynamic IP address.

And what to do if the address is gray, like, for example, almost everyone cellular operators for the above connection via USB-modem or backup?

KeenDNS solves this problem:

• Gives to the router even behind a gray address by a convenient name like home.keenetic.link without the hassle of obtaining and registering an SSL certificate;
• Opens access behind the gray address not only to the router, but also to the devices connected to it (for example, a heating boiler control system or the already mentioned torrent pump) by a friendly name like device.home.keenetic.link.
• Provides access to your home network over an all-pervasive SSTP tunnel that can be easily configured on Windows or via an Android app.

6. Create Time Machine backups

Apple stopped manufacturing its routers, but the need to backup MacBooks has not gone away.

Turn on Time Machine backups in your router's software settings. You will need an external hard drive again - now it will also become a backup storage. Moreover, it is not at all necessary to format it into apple file system HFS +, because the router can also make backups on an NTFS disk.

If you need high speed Reserve copy, Keenetic Omni may fail. Look towards the top-end Keenetic Giga or Ultra routers.

7. Control the flash drive from your smartphone without OTG cable

This function will allow you to record or view files if the computer is not at hand, and the smartphone does not support OTG, or the OTG cable has gone somewhere.

Connect the USB flash drive to the router software and run it on your smartphone file manager like "ES Explorer" with support for network access. You will have full access to the contents of the flash drive regardless of its file system.

8. Turn your router into a telephone exchange. Or something else

In the USB port of the router, you can plug not only a modem or disk, but also a proprietary DECT set-top box. With it, your router will work as a wireless telephone station with support for up to 6 handsets. Everything you need for this is possible without special knowledge.

Support for third party software packages () in official firmware turns the router into a real Swiss knife with a bunch of bells and whistles. You can put the torrent client rTorrent into the router, telephone exchange Asterisk IP PBX, another DLNA server and much more. In routers Keenetic does not change the main firmware, and you do not lose your warranty.

9. Save on VPN

Thanks to the latest events on the Russian Internet, everyone now knows about VPN and its advantages.

With the help of a router, you can save a lot by buying just one license for one device from some good VPN provider, but use the service on all your devices at once.

To do this, it is enough to turn on the VPN not on one of the devices, but directly on the router. Now any smartphone, tablet or computer connected to the router will automatically access the Internet via VPN. If this does not suit you, go to the router settings and specify which gadgets should work through the VPN and which should not.

If you only want to use a VPN to improve your internet security, you don't need overseas VPN servers, which means you don't need to pay for them either. With a white IP, you can safely access the Internet through your own VPN while away from home. As a bonus, you will have access to your home network and its contents from anywhere in the world.

10. Make Wi-Fi faster and more stable

Most routers operate in the 2.4 GHz band. When several routers are located side by side - for example, in an apartment building - they interfere with each other. Imagine a bazaar: a bunch of people, everyone is shouting, nothing is clear. It's the same with routers, only the quality and speed of the Internet drops.

The range is divided into several channels. For example, Vasya's neighbor's router works on channel 6, and Petya's on channel 11. The router is able to monitor the current congestion of channels and even automatically switch to the least populated ones, but the same function can be used by neighboring routers. What to do?

Create as many networks as your router allows. Give the networks dissimilar names so that your neighbors don't see through your cunning plan (and don't forget to put passwords). All networks you create will be on the same channel. For any Wi-Fi analyzer, the channel will seem congested, and therefore it will be considered inappropriate to create a grid in it. This means that the channel will remain completely at your disposal.

Why can't my router do that?

Much depends on the developer of the router software. Some devices receive updates and all the latest chips, while others remain on old version... Users of the latter have to get out and install custom firmware at their own peril and risk, losing the warranty on the device.

Keenetic uses a unified operating system that is constantly being improved and adds new features to all router models.

It doesn't matter if you use top-end Keenetic Giga or budget Keenetic Lite - you will always have the most fresh version operating systems with all new functions.

Naturally, hardware constraints come into play. It is impossible with the help software update grow a USB port to the router. A device built for 2.4 GHz only will never learn to operate in the 5 GHz band. But if the filling of the device meets the requirements for work new function, then you will receive it regardless of your Keenetic model.

(2.4 GHz and 5 GHz.)

(2.4 GHz and 5 GHz.)

Wi-Fi (pronounced as [wi-fi], short for Wireless Fidelity - a standard for equipment for broadband radio communications, designed for organizing local wireless networks Wireless LAN. The installation of such networks is recommended where the deployment of a cable system is impossible or economically impractical. handover function, users can move between access points across the Wi-Fi coverage area without breaking the connection Developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards.

Mobility

Mobile devices (PDAs and laptops) equipped with client Wi-Fi transmitting and receiving devices can connect to a local network and access the Internet through so-called access points or hotspots.

First Wi-fi

Wi-Fi was established in 1991 by NCR Corporation / AT&T (later Lucent and Agere Systems) in Nieuwegein, The Netherlands. Products originally intended for checkout systems were marketed under the WaveLAN brand and provided data transfer rates from 1 to 2 Mbps. Vic Hayes, the creator of Wi-Fi, has been called the "father of Wi-Fi" and was on a team that helped develop standards such as IEEE 802.11b, 802.11a, and 802.11g. In 2003, Vic left Agere Systems. Agere Systems could not compete on an equal footing 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 withdraw from the Wi-Fi market in late 2004.

Wireless-Fidelity - literally "Wireless Reliability".

Wi-Fi: How It Works
Typically, a Wi-Fi network scheme contains at least one access point (AP) and at least one client. The access point broadcasts its SSID (Service Set IDentifier, Network name) using special packets called signaling packets, transmitted every 100 ms. Signaling packets are transmitted at 1 Mbit / s and are small in size, so they do not affect the performance of the network. Since 1 Mbit / s is the lowest data transfer rate for Wi-Fi, a client receiving signal packets can be sure that it will be able to connect at a speed of at least 1 Mbit / s. Knowing the network parameters (that is, the SSID), the client can find out if it is possible to connect to this access point. The program built into the client's Wi-Fi card can also affect the connection. When two access points with identical SSIDs come into range, the program can choose between them based on the signal strength. The Wi-Fi standard gives the client complete freedom in choosing criteria for connection and roaming. This is the advantage of Wi-Fi, although it means that one of the adapters can do this much better than the other. Latest Versions operating systems contain a feature called zero configuration that shows the user all available networks and allows them to switch between them on the fly. This means that roaming will be completely controlled by the operating system. Wi-Fi transmits data over the air, so it has properties similar to nonswitched ethernet networks, and can experience the same problems as when working with nonswitched ethernet networks.

Wi-Fi and Cell Phones

Some believe that Wi-Fi and similar technologies may eventually replace cellular networks such as GSM. The obstacles to this development in the near future are the lack of roaming and authentication capabilities (see 802.1x, SIM cards and RADIUS), limited frequency range and severely limited Wi-Fi range. It seems more correct to compare Wi-Fi with other standards of cellular networks, such as GSM, UMTS or CDMA. However, Wi-Fi is ideal for using VoIP in corporate networks or in a SOHO environment. The first samples of equipment were already available in the early 90s, but did not enter commercial operation until 2005. Then the companies Zyxel, UT Starcomm, Samsung, Hitachi and many others introduced the VoIP Wi-Fi phones to the market at “reasonable” prices. In 2005 ADSL ISPs started to provide VoIP services to their customers (eg German ISP XS4All). When VoIP calls became very cheap, and often free, VoIP providers were able to open new market- VoIP services. GSM phones with integrated support for Wi-Fi and VoIP capabilities have begun to enter the market and have the potential to replace wired phones. Direct comparisons between Wi-Fi and cellular networks are currently impractical. Phones using only Wi-Fi have a very limited range, so deploying such networks is very expensive. However, the deployment of such networks can be the best solution for local use, for example, in corporate networks. However, devices that support multiple standards can gain significant market share.

Commercial use of Wi-Fi

Commercial access to Wi-Fi-based services is available in places such as Internet cafes, airports, and cafes around the world (commonly referred to as Wi-Fi cafes), but coverage can be considered sparse compared to cellular networks:. Ozone and OzoneParis In France. In September 2003, Ozone began rolling out the OzoneParis network through The City of Lights. The ultimate goal is to create centralized network Wi-Fi completely covering Paris. The basic tenet of the Ozone Pervasive Network is that it is a nationwide network. ... WiSE Technologies provides commercial access to airports, universities, and independent cafes throughout the United States; ... T-Mobile powers Starbucks hotspots in the US and UK, as well as over 7,500 hotspots in Germany; ... Pacific Century Cyberworks provides access to Pacific Coffee stores in Hong Kong; ... Columbia Rural Electric Association Seeks To Deploy 2.4 GHz Wi-Fi In A 9,500 Km Site Between Walla Walla and Columbia Counties in Washington State and Yumatilla, Oregon; Other major networks in the US also include: Boingo, Wayport and iPass; ... Sify, an Indian Internet Service Provider, has installed 120 hotspots in Bangalore, hotels, galleries and government offices. ... Vex has a large hotspot network located throughout Brazil. Telefonica Speedy WiFi has started to provide its services on a new growing network that has spread to the state of Sao Paulo. ... BT Openzone owns many UK hotspots operating at McDonald's and has roaming agreements with T-Mobile UK and ReadyToSurf. Their clients also have access to The Cloud hotspots. ... Netstop provides access in New Zealand. ... Golden Telecom supports the city Wi-Fi network in Moscow, and also provides its own communication channels for the implementation of the Yandex.Wi-Fi () project. ... EarthLink plans to fully connect Philadelphia (USA) to the wireless Internet in the third quarter of 2007. It will be the first metropolitan city in the United States to be fully covered by Wi-Fi. The cost will be in the range of $ 20-22 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. Other areas will be connected as the transmitters are installed.

Wireless technologies in industry

For industrial use, Wi-Fi technologies are still offered by a limited number of suppliers. This is how Siemens Automation & Drives offers Wi-Fi solutions for their SIMATIC controllers in accordance with the IEEE 802.11b standard in the free ISM 2.4-GHz band and providing a maximum transmission rate of 11 Mbps. These technologies are used mainly for the control of moving objects and in warehouse logistics, as well as in cases where, for any reason, it is impossible to lay wired Ethernet networks.

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 that come with special software. For example FON is a young Spanish company established 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, which provide free Internet access; bills selling their frequency range; and aliens using bills access. Thus, the system is similar to peer-to-peer services. While FON is receiving financial backing from companies like Google and Skype, it will only be clear over time whether this idea will actually work. There are three main problems with this service right now. The first is that more attention from the public and the media is required to move the project from the initial stage to the main stage. You should also take into account the fact that the provision of access to your Internet channel to others may be limited by your agreement with the Internet provider. Therefore, ISPs will try to protect their interests. Likewise, record companies who oppose the free distribution of MP3s are likely to do the same. And thirdly, software FON is still in beta testing, and it only remains to wait for the security issue to be resolved.

Free Wi-Fi

Bye commercial services trying to leverage existing business models for Wi-Fi, many groups, communities, cities, and individuals are building free Wi-Fi networks, often using a shared peer-to-peer agreement so that networks can communicate freely with each other. Free wireless networks are usually seen as the future of the Internet. Many municipalities are teaming up with local communities to expand free Wi-Fi networks. Some groups are building their Wi-Fi networks entirely based on volunteers and donations. For more information, see the Shared Wireless Networks section, where you can also find a list of free Wi-Fi networks located around the world (see also Free hotspots Wi-Fi access in Moscow). OLSR is one of the protocols used to create free networks. Some networks use static routing, while others rely entirely on OSPF. Wireless Leiden has developed its own routing software called LVrouteD to interconnect Wi-Fi networks built on a fully wireless basis. Most of the networks are based on software with open source, or publish their schema under an open source license. Some smaller countries and municipalities already provide free Wi-Fi hotspots and Wi-Fi Internet access in the community 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 Internet access without restriction to all those contributing to the development of the Pervasive Network by providing the roof of their home for the installation of a Wi-Fi network. Unwire Jerusalem is a project to install free Wi-Fi hotspots in major shopping malls in Jerusalem. Many universities provide free Wi-Fi Internet access to their students, visitors, and anyone on campus. Some commercial organizations, such as Panera Bread, provide free Wi-Fi access to loyal customers. McDonald's Corporation also provides Wi-Fi access under the McInternet brand. The 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, and those who do not belong to it are paid access. An example of such a service is the Sparknet network in Finland. Sparknet also supports OpenSparknet, a project in which people can make their own hotspots part of the Sparknet network for some benefit. V recent times commercial Wi-Fi providers are building free Wi-Fi hotspots and hot zones. They believe that free Wi-Fi will attract new customers and return on investment.

Benefits of Wi-Fi

Allows you to deploy a network without laying a cable, can reduce the cost of deploying and expanding the network. Locations where cable cannot be installed, such as outdoors and in buildings of historical value, can be served by wireless networks. ... Wi-Fi devices are widespread in the market. And devices from different manufacturers can interact at a basic service level. ... Wi-Fi networks support roaming, so the client station can move in space, moving from one access point to another. ... Wi-Fi is a set of global standards. Unlike cell phones, Wi-Fi equipment can work in different countries around the world.

Disadvantages of Wi-Fi

The frequency range and operating limits vary from country to country; in many European countries, two additional channels are allowed, which are prohibited in the United States; Japan has another channel at the top of the range, while other countries, such as Spain, prohibit the use of low frequency channels. Moreover, some countries, such as Italy, require registration of all outdoor Wi-Fi networks, or require registration of a Wi-Fi operator. ... Power consumption is quite high compared to other standards, which reduces battery life and increases the temperature of the device. ... The most popular encryption standard, Wired Equivalent Privacy or WEP, can be hacked relatively easily even with the correct configuration (due to weak key strengths). Although newer devices support the more advanced Wi-Fi Protected Access (WPA) protocol, many older access points do not support it and need to be replaced. The adoption of the 802.11i (WPA2) standard in June 2004 makes available a more secure scheme that is available in new hardware. Both schemes require a stronger password than those typically assigned by users. Many organizations use additional encryption (such as VPN) to protect against intrusion. ... Wi-Fi has a limited range. Typical home Wifi router standard 802.11b or 802.11g has a range of 45 meters indoors and 90 meters outdoors. Distance also depends on frequency. Wi-Fi in the 2.4 GHz band works farther than Wi-Fi in the 5 GHz band and has a smaller radius than Wi-Fi (and pre-Wi-Fi) at 900 MHz. ... Overlapping signals from a closed or encrypted access point and an open access point operating on the same or adjacent channels can prevent access to an open access point. This problem can arise with a high density of hotspots, for example, in large apartment buildings, where many residents put their Wi-Fi hotspots. ... Incomplete interoperability between devices from different manufacturers or incomplete standard compliance may result in limited connectivity or slower speeds.

Wi-Fi gaming

Wi-Fi is compatible with game consoles and PDAs and allows you to play networked games over any access point. ... Iwata, President of Nintendo, announced a Wi-Fi compatible Nintendo Wii, also saying games like Super Smash Brothers will be available. The Nintendo DS game console is also Wi-Fi compatible. ... The Sony PSP has one-button wireless networking support for Wi-Fi hotspots or other wireless connections.

Wi-Fi and free software

BSD OS (FreeBSD, NetBSD, OpenBSD) can work with most adapters since 1998. Drivers for Atheros, Prism, Harris / Intersil and Aironet chips (from the respective Wi-Fi device manufacturers) are usually included in BSD OS version 3. Darwin and Mac OS X, despite overlapping with FreeBSD, have their own unique implementation ... In OpenBSD 3.7, more drivers for wireless chips were included, including RealTek RTL8180L, Ralink RT25x0, Atmel AT76C50x, and Intel 2100 and 2200BG / 2225BG / 2915ABG. This partially resolved the problem of lack of open wireless chip drivers for OpenBSD. It is possible that some drivers implemented for other BSD systems can be ported if they have not been created yet. Ndiswrapper is also available for FreeBSD. ... Linux: Starting with version 2.6, support for some Wi-Fi devices appeared directly in the Linux kernel. Support for Orinoco, Prism, Aironet and Atmel chips is included in the mainline kernel, ADMtek and Realtek RTL8180L chips are supported by both proprietary manufacturers and open source drivers written by the community. Intel Calexico is supported by open source drivers available from Sourceforge. Atheros and Ralink RT2x00 are supported through open source projects. Support for other wireless devices is available when using open driver ndiswrapper which allows Linux systems running on Intel x86 computers, "wrap" the manufacturer's Windows drivers for direct use. At least one commercial implementation of this idea is known. FSF has created a list of recommended adapters, more detailed information can be found on the Linux wireless site.

Wireless Standards

On this moment There are four main Wi-Fi standards - these are 802.11a, 802.11b, 802.11g, and 802.11i. Two of them are used in Russia: 802.11b and 802.11g. In 2006, 802.11i should appear in Russia. By 2007, it is planned to start introducing another standard - 802.11n.

This is the first wireless standard which appeared in Russia and is still used everywhere. The transmission speed is rather low, and the security is quite low. If desired, an attacker can take less than an hour to decrypt the network key and infiltrate your local area network... For protection, the WEP protocol is used, which did not characterize itself well and was hacked several years ago. We recommend that you do not use this standard not at home, much less in corporate computer networks. An exception may be those cases when the equipment does not support another, more secure standard.

- Speed: 11 Mbps
- Radius: 50 m
- Security protocols: WEP
- Security level: low

This is a more advanced standard that replaced 802.11b. The data transfer rate has been increased by almost 5 times, and now it is 54 Mbps. When using equipment that supports superG * or True MIMO * technology, the maximum speed limit is 125 Mpbs. The level of protection has also increased: if all the necessary conditions are met with the correct settings, it can be assessed as high. This standard is compatible with the new WPA and WPA2 * encryption protocols. They provide a higher level of security than WEP. Cases of WPA2 * protocol hacking are not yet known.

* - Not supported by all hardware

- 54 Mbps, up to 125 * Mbps
- Radius: 50 m
*

it new standard, the implementation of which is just beginning. In this case, support for the most modern technologies, such as True MIMO and WPA2, is built directly into the standard itself. Therefore, the need for a more careful selection of equipment is eliminated. It is planned that this standard will replace 802.11g and nullify all hacking attempts.

- Speed: 125 Mbps
- Radius: 50 m
- Security protocols: WEP, WPA, WPA2
- Security level: High

A future standard that is currently being developed. This standard is intended to provide longer wireless coverage distances and higher speeds, up to 540 Mbps.

- Speed: 540 Mbps
- Radius: unknown m
- Security protocols: WEP, WPA, WPA2
- Security level: High

However, it should be remembered that incorrect configuration of equipment that supports even the most modern technologies protection, will not provide the proper level of security for your network. Each standard has additional technologies and settings to increase the level of security. Therefore, we recommend that you trust the setting Wi-Fi equipment only for professionals.

Wireless Security

Special attention should be paid to the security of wireless networks. After all, wi-fi is wireless network and, moreover, with a large radius of action. Accordingly, an attacker can intercept information or attack your network from a safe distance. Fortunately, there are many different ways to protect yourself today, and if configured correctly, you can be confident that the level of security you need is adequate.

An encryption protocol that uses a rather weak RC4 algorithm on a static key. There are 64-, 128-, 256- and 512-bit wep encryption. The more bits are used to store the key, the more possible key combinations, and, accordingly, the higher the network's resistance to cracking. The wep part of the key is static (40 bits in the case of 64-bit encryption), and the other part (24 bits) is dynamic (initialization vector), that is, it changes during the network operation. The main vulnerability of the wep protocol is that the initialization vectors are repeated after a certain period of time and the cracker only needs to collect these repeats and calculate the static part of the key from them. To increase the level of security, you can use the 802.1x or VPN standard in addition to wep encryption.

Stronger encryption protocol than wep, although the same RC4 algorithm is used. A higher level of security is achieved through the use of the TKIP and MIC protocols.

- TKIP (Temporal Key Integrity Protocol). A dynamic network key protocol that changes frequently. In this case, each device is also assigned a key, which also changes.
- MIC (Message Integrity Check). Packet integrity check protocol. Protects against packet sniffing and redirection.

It is also possible to use 802.1x and VPN, as is the case with wep.

There are two types of WPA:

- WPA-PSK (Pre-shared key). A passphrase is used to generate network keys and to log on to the network. Ideal for a home or small office network.
- WPA-802.1x. The network is logged on through the authentication server. Optimal for a large company network.

Improvement of the WPA protocol. Unlike WPA, the stronger AES encryption algorithm is used. Similar to WPA, WPA2 is also divided into two types: WPA2-PSK and WPA2-802.1x.

A security standard that includes several protocols:

- EAP (Extensible Authentication Protocol). Extended Authentication Protocol. Used in conjunction with a RADIUS server in large networks.
- TLS (Transport Layer Security). A protocol that ensures the integrity and encryption of transmitted data between the server and the client, their mutual authentication, preventing interception and spoofing of messages.
- RADIUS (Remote Authentication Dial-In User Server). Server for user authentication by login and password.

VPN (Virtual Private Network) - Virtual private network. This protocol was originally created for secure connection clients to the network via public Internet channels. The principle of VPN operation is the creation of so-called secure "tunnels" from the user to the access point or server. Although VPN was not originally created for WI-Fi, it can be used on any type of network. The most common VPN protocol used to encrypt traffic is IPSec. It provides almost one hundred percent safety. There are no known cases of VPN hacking at the moment. We recommend using this technology for corporate networks.

Additional protection methods

- Filtering by MAC address.

MAC address is a unique identifier for the device ( network adapter), "Wired" into it by the manufacturer. On some equipment, it is possible to enable this function and allow access to the network to the necessary addresses. This will create an additional obstacle to the attacker, although not very serious - the MAC address can be spoofed.

- Hide SSID.

SSID is the identifier for your wireless network. Most of the equipment allows you to hide it, so when scanning wi-fi networks, your network will not be visible. But again, this is not too much of a barrier if the attacker uses a more advanced network scanner than the standard Windows utility.

- Denying access to the settings of an access point or router via a wireless network.

By activating this function, you can deny access to the settings of the access point through Wi-fi network however, this will not protect you from eavesdropping traffic or infiltrating your network.

Keep in mind that improperly configured hardware that supports even the most advanced security technologies will not provide the proper level of security for your network. Each standard has additional technologies and settings to increase the level of security. Therefore, we recommend that you trust Wi-Fi setup equipment only for professionals.

The article is taken from open sources.
http://ra4a.narod.ru/Spravka5/Wi-Fi.htm

Nowadays, almost every apartment and house has its own wireless network with Internet access. Such a network greatly simplifies the use of Internet resources. However, few people know how such a network works, what a router is, and at the same time, quite a few people would like to understand the principle of operation of such equipment. This is what will be discussed below. We will tell you how a router works and what its main functions are.

What is a router

Probably the most important question to start with is what a router is and how it works. The word "router" itself is English and literally means "router". This means that the device assigns certain routes.

To explain this correctly, you need to describe, at least in a nutshell, how the network works. There is a subscriber and server device. The server performs the functions base station... It is through it that all requests originating from the subscriber's PCs pass. In turn, subscriber computers issue requests, so-called data packets (each packet has a destination address), the server receives these packets and sends a response. In this scheme, the router acts as a server station.

If the router is connected to the global network, then it simply redirects data packets from the PC to the server (provider), being an intermediary. What is the purpose of the router - to collect requests from computers and redirect them further to the provider, and the provider redirects them even further - to other server stations, and so on.

The router itself is a whole mini-computer. It has its own central processor, its own RAM and different modules communication.

Thanks to this, the router has the ability to receive and process signals, create a reliable protection scheme, control data flows, and so on.

So, we have figured out what kind of device it is, now let's move on to the question of how a Wi-Fi router works.

Principle of operation

We already know that the principle of a router is to assign and redistribute data streams (specific routes) between subscriber devices and server stations. It is worth noting that the default access speed between different devices divided equally. In other words, the memory of the router contains a certain routing table, which contains certain protocols that the entire system uses.

It is this table that determines the paths along which data packets are sent: it contains all the addresses of the connected computers and the provider (that is, all the devices that are included in the network).

Thanks to this table, organized network, in which each signal has its own path and does not interrupt with others. Moreover, the router scheme is configured in such a way that each signal from each connected computer has the most optimal route and the minimum response time.

Of course, this is not yet the answer to the question of how a Wi-Fi router works. There are a lot of subtleties and nuances here. For example, each connected device gets its own unique address. DHCP is responsible for this. And in order to find the most optimal route for each of the connected PCs, the router from time to time sends a signal to each of the addresses. This allows the network information to be kept up to date, keeping the map of the entire network up to date - this is called Dynamic Routing.

DHCP is very convenient function... However, in some cases, for security reasons, this function must be disabled. If the DHCP server is disabled, then the network parameters (in particular the network address) are set manually, which eliminates certain errors - this is called "Static Routing".

Wireless protocols

Since we have a question about how a Wi-Fi router for home works, it is worth paying attention wireless... In fact, this is the most common radio communication. It should be noted here that there are different protocols for this communication and they work at different frequencies:

• 802.11b - 2.4 GHz. This is an outdated protocol that allows data transfer at speeds up to 11 Mbps;
• 802.11g - a newer solution, although it works at the same frequency, the connection speed has been increased to 54 Mbps;
• 802.11n is a new standard that operates at 2.4GHz and 5GHz. By changing the signal frequency, it was possible to avoid a lot of Wi-Fi disadvantages associated with interrupting the radio signal, as well as to increase the transmission speed to 300 Mbit / s (in theory, up to 600 Mbit / s). It is noteworthy here that this standard works in two frequency ranges at once, due to which both old and new devices can work with such a protocol.

There are other standards, however, they are rarely used at home, since this simply does not make sense. After all, most modern providers provide speeds of no more than 100 Mbps. The most recent standard is 802.11ac, which allows data transfer rates up to 7 Gigabits.

It is also worth noting here that the higher the speed, the smaller the coverage radius. This is due to the principle of radio waves. The old standards (802.11b and g) have a larger coverage radius than the newer ones - ac. But ac has a higher data transfer rate.

Principle of operation Wi-Fi router always remains the same - the intermediary between the subscriber device and the provider. Only the way of connecting to the router changes.

Conventional desktop computers are not equipped with wireless modules and the only connection option for them remains cable connection... However, if we talk about laptops, smartphones and tablets, then all these devices are equipped with Wi-Fi modules, which allows you to connect to the network without using any wires.

It is worth noting that since a laptop (smartphone or tablet) is equipped with a wireless adapter, it can be used not only to receive signals, but also to distribute the network, turning the laptop into a virtual router.

The question arises, how does a Wi-Fi router work on a computer? There are no differences here. Operating system itself has a built-in routing table, and therefore, creating a virtual network (distribution), you simply use this table, and the computer will perform the functions of the same router.

So, we looked at what it is - a Wi-Fi router, and how it works. Now let's look at how the security system works. This is an important issue, since a network breach can lead to the loss of personal data that an attacker can use for his own purposes. Besides, outside user can hack the network, just to access the Internet "for free", but many have certain restrictions on both speed and traffic. Therefore, you should think about safety first.

It should be noted right away that there are different modes of operation of the security system, which you yourself can configure. In order to configure the security mode, you will need. Next, you need to go to the "Wireless mode" or "Wi-Fi" section (on different models may be different). Here you will find the subsection “Security” or “Wireless Security”.

Next, you just need to select the mode of operation of the Wi-Fi router. Typically, home networks use WPA-PSK or WPA2-PSK simplified security. To avoid certain annoyances, it is best to choose WPA-PSK WPA2-PSK mixed mode. After choosing this mode, all that remains is to assign (invent and enter) a complex password and save the parameters.

If we talk about corporate networks, then everything is more complicated here. Such networks require more high level protection, as theft of corporate data entails more serious consequences. Therefore, many routers have a security mode such as WPA-WPA2 Enterprise. Here I will only clarify that this function used only by system administrators in serious companies, when protection comes first.

So we spent short review how a router works - for dummies. Of course, this is a very broad topic and there are many nuances here. But in general, we examined the purpose of the router and the very essence of its work.

How the Router Works: Video

Wi-Fi is now the most popular data transmission technology in wireless computer networks... The name is a trademark that belongs to the wi-fi alliance. Technical description technology is contained in the IEEE 802.11 standard.

Previously, Wi-Fi was decoded as "Wireless Fidelity" wireless accuracy, but now it is believed that Wi-Fi is decrypted in any way and just looks like a play on Hi-Fi words, that is, high quality.

In order for the manufacturer to name his equipment Wi-Fi, he must submit it for inspection to the Wi-Fi Alliance. This company verifies how the equipment meets the requirements of the IEEE 802.11 standard. And the right to use brand Wi-Fi is given after the Wi-Fi Alliance is satisfied that the equipment is fully IEEE 802.11 compliant.

For comparison, for ethernet, such a check is not performed, the manufacturer can create equipment that works according to the 802.3 standard and its modifications and call it an Ethernet switch

Wi-Fi location in

Wi-Fi, like Ethernet, is located at the physical and link layer, and the link uses two sublayers, the MAC media access control sublayer and the LLC logical link control sublayer.

Wi-Fi operating mode

Wi-Fi can work in two modes, most often the infrastructure wifi mode is used in which there is wireless equipment, the so-called access points, which are connected to a wired network and then to the Internet. Nowadays, Wi-Fi is most often used to connect to the Internet. Therefore, the infrastructure mode is the most popular.

Another connection option is also possible, a peer-to-peer network, where computers communicate without any access points, directly with each other.

Wi-Fi and Ethernet

Wi-Fi technology is very similar to Ethernet technology, one might say, adapted in a wireless environment. For addressing wifi is used in the same way as in Ethernet.

For data transmission, a shared medium is used, as in classic Ethernet. Only in classic Ethernet, the signal is transmitted through the cable, and in wifi, electromagnetic radiation (radio air) is used.

The frame format at the LLC level for Wi-Fi and Ethernet is the same, IEEE 802.2. In practice, this means if you use wireshark to capture packets that go over the network, then regardless of whether your frame came from Ethernet or from Wi-Fi, its format will be the same. Although in the process of transmission over the wireless medium at the MAC layer, Wi-Fi uses a different frame format.

Wi-Fi Physical Layer Standards

There are several different options for implementing Wi-Fi, they are described in 6 standards. The very first 802.11 standard was adopted in 1997 and had a speed of 1 or 2 Mb / s, Ethernet at that time could transfer information at a speed of 10 Mb / s. The modern wifi standard 802.11ac was adopted in 2014, the maximum transmission speed is more than 6 Gb / s.

Now Wi-Fi is used for data transmission - electromagnetic radiation or radio air, but in the first version of Wi-Fi infrared radiation was used, now this method is used in TV remotes.

But since the second generation of the 802.11b standard, only electromagnetic radiation has been used. The two frequencies used are 2.4 and 5 GHz. Frequencies in this range can be used without licensing. However, other devices also work in the same range, for example a microwave oven, and this interferes with the transmission of the Wi-Fi signal.

Signal presentation

Modern wi-fi standards use Orthogonal Frequency Division Multiplexing (OFMD) for data transmission. Data is transmitted in parallel at different frequencies.Although the frequencies in the picture overlap each other, the OFMD method can reliably identify signals.

Channels in the 2.4 GHz band

Channels in the 2.4 GHz band are used for data transmission 14 channels, the picture lists their frequencies. The channels are slightly shifted relative to each other, but still partially overlap.

Thus, the number of wi-fi networks that are in the same place is limited by the number of channels; there cannot be more than 14. If more than 14 networks work in the same area, they will not have enough channels. This situation is known as "Wi-Fi jungle" and it is quite common, for example, in residential buildings where a Wi-Fi router is installed for Internet access in each apartment.

Wi-fi channel width

Wi-Fi can use channels of different widths. The channel width is the difference between the maximum and minimum frequency to which data can be transferred. The wider the channel, the more qualitatively we can transfer data, therefore, the higher the data transfer rate.

In the 802.11n standard, it became possible to use 40 MHz channels and thereby increase the transmission speed. In the latest 802.11ac Wi-Fi standard, 80 MHz and 160 MHz channel widths can be used. However, support for 160 MHz channels is provided whenever possible and at the request of the manufacturer.

Spatial flow

In the 802.11n standard, it became possible to use multiple antennas for transmitting and receiving data. This feature is also used in the modern standard.

If we have several antennas, then we can use several spatial streams - this is a signal that is transmitted from one antenna to another.

If we transmit several spatial streams in parallel, then the data transfer rate increases. This uses a special signal coding method called MIMO - multiple transmission and multiple reception.

Example: we have 3 antennas, at the transmitting station and three at the receiving station. Each antenna at the transmitting station (Tx) sends its own spatial stream, so we increase the transmission rate by 3 times. At the receiving station, all three antennas receive 3 spatial streams, and using the mimo coding method, they are able to separate them and improve the signal quality for each separate spatial stream.

Speed ​​adaptation

In Ethernet, the speed of the equipment is fixed, it will be the same for all devices on the network. Weifai, on the other hand, allows you to change the speed depending on the signal quality. If the signal quality is high, then the speed increases, and if it is low, then the speed decreases. In order to increase or decrease the speed, Wi-Fi changes several parameters:

• You can use different channel widths from 20 MHz to 160 MHz.
• Supports a variety of modulations that allow data to be transmitted at different rates and reliability
• It is possible to change the interval of data between characters that are transmitted via Wi-Fi.

The table that shows different variants speeds for one spatial stream of Wi-Fi. The lowest speed of 6.5 Mbps is obtained using 20 MHz BPSK BPSK and 800 ns symbol spacing. The fastest rate of 866 Mb / s is obtained using IAM with 256 states, a 160 MHz channel and a 400 ns symbol spacing.

The data is presented for one spatial stream, if your access point and your station have multiple antennas, then you can use multiple spatial streams and thereby further increase the transmission rate.

Protocol Wireless fidelity was developed, scary to think, in 1996. At first, it provided the user with a minimum data transfer rate. But after about every three years, new Wi-Fi standards were introduced. They increased the speed of reception and transmission of data, and also slightly increased the width of the coverage. Each a new version protocol is indicated by one or two Latin letters following the numbers 802.11 ... Some Wi-Fi standards are highly specialized - they have never been used in smartphones. We will only talk about those versions of the data transfer protocol that an ordinary user needs to know about.

The very first standard did not have any letter designation. It was born in 1996 and has been in use for about three years. Data over the air using this protocol was downloaded at a speed of 1 Mbit / s. This is extremely small by modern standards. But let's remember that about going to the "big" Internet with portable devices then there was no question. In those years, even WAP was not really developed yet, Internet pages in which rarely weighed more than 20 Kb.

Overall, the benefits new technology then no one appreciated. The standard was used for strictly specific purposes - for debugging equipment, remote configuration of a computer and other intricacies. Ordinary users in those days about cell phone could only dream, but the words “ wireless transmission data ”became clear to them only after a few years.

However, low popularity did not stop the protocol from evolving. Gradually, devices began to appear that increase the power of the data transmission module. The speed with the same version of Wi-Fi has doubled - up to 2 Mbps. But it was clear that this was the limit. That's why Wi-Fi Alliance(an alliance of several large companies created in 1999) had to develop a new standard that would provide higher throughput.

Wi-Fi 802.11a

The first creation of the Wi-Fi Alliance was the 802.11a protocol, which also did not become very popular. Its difference was that the technique could use the 5 GHz frequency. As a result, the data transfer rate has grown to 54 Mbps. The problem was that this standard was incompatible with the previously used 2.4 GHz frequency. As a result, manufacturers had to install a dual transceiver to operate on both frequencies. Needless to say, this is not a compact solution at all?

In smartphones and mobile phones this version the protocol was practically not used. This is explained by the fact that after about a year, a much more convenient and popular solution came out.

Wi-Fi 802.11b

When designing this protocol, the creators returned to the 2.4 GHz frequency, which has an undeniable advantage - a wide coverage area. The engineers managed to achieve that gadgets have learned to transfer data at speeds from 5.5 to 11 Mbps. All routers immediately began to receive support for this standard. Gradually, such Wi-Fi began to appear in popular portable devices. For example, the E65 smartphone could boast of its support. Most importantly, the Wi-Fi Alliance ensured compatibility with the very first version of the standard, so that the transition period passed completely unnoticed.

Until the end of the first decade of the 2000s, it was the 802.11b protocol that was used by numerous technologies. The speeds provided by them were enough for smartphones, and portable game consoles, and laptops. Almost all modern smartphones support this protocol. This means that if you have a very old router in your room that cannot transmit a signal using more modern versions of the protocol, the smartphone will still recognize the network. Although you will definitely be unhappy with the speed of data transfer, since now we are using completely different speed standards.

Wi-Fi 802.11g

As you already understood, this version of the protocol is backward compatible with the previous ones. This is explained by the fact that the operating frequency has not changed. At the same time, the engineers managed to increase the speed of receiving and sending data to 54 Mbps. The release of the standard took place in 2003. For some time, this speed seemed even excessive, so many manufacturers of mobile phones and smartphones delayed its implementation. Why do you need such a fast data transfer, if the amount of built-in memory of portable devices was often limited to 50-100 MB, and full-fledged Internet pages were simply not displayed on a small screen? And yet, gradually, the protocol gained popularity, mainly due to laptops.

Wi-Fi 802.11n

The most ambitious update of the standard happened in 2009. The Wi-Fi 802.11n protocol was born. At that time, smartphones had already learned how to display heavy web content with high quality, so the new standard came in handy. Its differences from its predecessors were in the increased speed and theoretical support for the 5 GHz frequency (while 2.4 GHz also did not disappear). For the first time, technology support was introduced into the protocol MIMO... It consists in supporting the reception and transmission of data simultaneously over several channels (in this case, two). This allowed, in theory, to achieve speeds of 600 Mbps. In practice, however, it rarely exceeded 150 Mbps. The presence of interference on the signal path from the router to the receiving device affected, and many routers lost MIMO support to save money. Likewise, budget devices still did not get the opportunity to work at 5 GHz. Their creators explained that the 2.4 GHz frequency at that moment was not yet heavily loaded, and therefore the buyers of the router did not really lose anything.

The Wi-Fi 802.11n standard is still actively used. Although many users have already noted a number of its shortcomings. First, because of the 2.4 GHz frequency, it does not support aggregation of more than two channels, which is why the theoretical speed limit is never reached. Secondly, in hotels, shopping centers and other crowded places, channels begin to overlap, which causes interference - web pages and content are loaded very slowly. All these problems were solved by the release of the next standard.

Wi-Fi 802.11ac

At the time of this writing, the newest and fastest protocol. If the previous types of Wi-Fi worked mainly in the 2.4 GHz frequency, which has a number of limitations, then strictly 5 GHz is used here. This has almost halved the coverage width. However, router manufacturers decide this problem installation of directional antennas. Each of them sends a signal in its own direction. However, some people will find this inconvenient for the following reasons:

• Routers turn out to be cumbersome, since they include four or even more antennas;
• It is advisable to install the router somewhere in the middle between all serviced premises;
• 802.11ac Wi-Fi routers consume more electricity than older and budget models.

The main advantage of the new standard is a tenfold increase in speed and expanded support for MIMO technology. From now on, up to eight channels can be combined! As a result, the theoretical data flow is 6.93 Gbps. In practice, the speeds are much lower, but even they are quite enough to watch some 4K movie online on the device.

For some people, the possibilities of the new standard seem overkill. Therefore, many manufacturers do not implement its support in. The protocol is not always supported, and even by rather expensive devices. For example, it lacks support (2016), which, even after the price tag has been cut, cannot be attributed to the budget segment. Finding out which Wi-Fi standards your smartphone or tablet supports is quite simple. To do this, see its complete specifications on the Internet, or run.