Wireless Internet technologies air max. What is AirMax? More details on subscriber devices, antennas

Increasingly from the lips of people planning to organize networks wireless internet planning to use Ubiquti Network equipment, you may hear the question: what is AirMax?

Briefly, we can say about AirMax technology this way: it is a special radio protocol that allows you to work with wireless networks that have a main signal frequency of 2.4 (5) GHz. It's not hard to guess: the protocol was developed by one company, Ubiquti Networks. Users immediately noticed: the name of the AirMax protocol is similar to “WiMAX”. Probably, this cannot be considered an accident, rather a marketing ploy (but nothing more) - to WiMAX standard connection, AirMax refers indirectly.

The ubiquiti airmax protocol was and is a closed development, information about it can be disclosed within the company itself, that is, it is difficult to find any reviews that can explain all the details and specifics of the AirMax implementation. Devices from other manufacturers cannot work with this protocol, but not all Ubiquti Networks equipment works with it.

So what's the point? A user of the AirMax protocol will receive several benefits. First of all, scalability. That is, you can work without reducing quality, under conditions of simultaneous switching on large number clients. In Wi-Fi 802.11 networks, for example, the standard recommends simultaneous activation 20 users (or less). With the help of AirMax technologies, up to 120 clients will be able to work simultaneously in this radio channel (this is achieved by changing the principles of transmission at the MAC level). Additionally, we will say that AirMax uses the so-called customer survey technology (polling). It allows you to solve the problem of “hidden nodes” (discussed below).

The use of ubiquiti airmax requires specific equipment. But the protocol allows you to minimize transmission delay intervals. When polling clients (there are clients and a “station”), a higher priority is set for those who are more “dependent” on delays (for example, for content such as video, voice). Which is very important (which 802.XX protocols do not have).

In addition, it has been achieved high speed exchange. Although, the “achievement” cannot be attributed only to the company’s merits: speed here is achieved by using MIMO technologies, increasing throughput by physical level. Ubiquti Networks has developed unique cross-polarization antennas, the characteristics of which are close to antennas in the professional operator segment.

Before purchasing devices, you should find out exactly what characteristics specific components that support AirMax have. Reviews for ubiquiti are always positive. Next, we will look at what exactly includes a local network segment that implements AirMax technology.

Base station and subscriber devices

The equipment option and example proposed here is intended for building a system (including up to 300 subscribers) using one base station. Based on the use of Ubiquti products, we are building a wireless network with a “star” topology.

The equipment operates in a 5 GHz or 2.4 GHz channel (the setup and connection process is completely identical). And - the first requirement: always choose equipment designed for one band.

Base station requirements

1. Availability LAN connections to the Internet with sufficient speed. If there are hundreds of “clients” and the network is for provisioning, this parameter is key.
2. It is advisable to have a router (Mikrotik, Cisco, etc.) necessary to manage IP addresses, bandwidth and traffic prioritization. For a “small” provider, they recommend Mikrotik Routerboard RB450G (for “medium” networks, “1100” is better). RB450G is an inexpensive solution without sacrificing functionality.
3. Instead of a router, you can use a switch.
4. To build such a system, you need 3 identical AirMax BaseStation antennas (120 degrees), or a ready-made AirMax BaseStation array (four 90 degrees each) - both will provide performance and high throughput.
5. You need access points designed for the base station. The Ubiquti company has a model called Rocket M5 (the number of access points coincides with the number of connected antennas; in the case of 4 emitters, you will have to buy four Rocket M5).

PoE-24 is a power supply included in the standard kit. Rocket M5 can only be “powered” via an FTP cable (see figure), therefore, power for transmission via this cable is properly “converted” (inside PoE-24).

Among the branded subscriber devices are: Bullet M5, Nanostation M5, Nanostation Loco M5, Picostation M5, Airwire. All ubiquiti airmax equipment is tested for compatibility - but purchase devices of the same range. In case of breakdown/malfunction, any element is replaced with a new one (or a similar one with similar characteristics).

More details on subscriber devices, antennas

First of all, we will divide subscriber access points into 2 large classes: working without using external antennas(having a built-in circuit), and devices designed to work with an antenna.

Of course, they differ in characteristics such as maximum communication range (and transmitter power), but the price will increase proportionally.

The main representative of the first class of devices is the NanoStation LocoM5. The antenna is built-in here.

The LocoM5 model is more popular than others. You can work in any of the standards: Wi-Fi 802.11 (without using AirMax), or using the AirMax protocol. The communication range, however, is small (the distance from the device to the base station should not exceed 1 kilometer). PC connection interface (or local router) – standard LAN 100 Mbit. The device is powered by an external PoE-24 unit (discussed above), consuming power up to 12 VA. A more “powerful” access point is NanoStation M5.

In contrast to the LocoM5, consider the Bullet M5 (High Power class). Connecting to a PC and power supply is no different:

However, the antenna cable is screwed onto the external connector (on top of the device). Complete with an antenna (such as the following figure), the subscriber point is capable of operating at long distances to the base station.

The antenna is omnidirectional and works with the AirMax protocol. It must be said that such devices are sometimes unreasonably expensive (even more expensive than “active” devices).

Finally, you can buy an antenna with built-in electronics that connects directly to the FTP cable (another class of devices):

Here we present the AirGrid M model. As you can see, it is not omnidirectional (which is a “plus”: no energy is consumed); the communication range (distance to the base station) is also “not too much” (up to 3 km).

Ubiquiti also produces equipment used to create point-to-point WLANs. It is the most “long-range” (and expensive). However, any 2 subscriber points can be configured for this mode. Although, “point-to-point” does not use the AirMax ubiquiti protocol, there are reviews about this mode of operation.

Note: The power supply for ubiquiti equipment over FTP cable comes in two types (on different power): up to 12 Volt-Amps, and up to 24. For each subscriber device, the power consumption has one of these values ​​(in most cases, it is still 12).

Setting up a subscriber point

Let's look at an example of setting up NanoStation LOCO M5. If the necessary connections are made:

– NanoStation5 – to the power supply device (POE port) of the PoE-12 unit

– LAN port PoE-12 – in local network(to a PC, or to a switch/hub/router).

It takes 2-3 minutes to load the embedded operating system.

When connections are made and the device is booted, address bar your browser you need to dial: 192.168.1.20 (the address is indicated on the package). We go to the web interface, enter the password and login (the word ubnt), and see the window:

This is the main control menu (Main). Please pay attention to the parameters:

1. Base Station SSID – field contains the network name;
2. Signal strength - indication of radio signal strength;
3. Frequency - the range currently used by the network;
4. Security - whether there will be encryption.

Go to the WireLess tab:

Here are the basic settings

1. In the “Wireless Mode” line, select the “Access Point” mode. You change the “SSID” item if you know the name of the network for clients to work with the desired base station.
2. “Country Code” – leave it, or, to check the broadcast, select “Compilance test”.
3. The “Channel Width” line is responsible for the width of the microwave channel. 40 MHz, for example, will allow you to operate at up to 300 Mbit/s. “Channel shifting” – leave it “Disabled” (reduce interference for other devices).
4. Frequency – select the range (2.4/5 GHz).
5. Output Power – set the device power: “maximum for the base station.”
6. Accept changes: “Change”.
7. To the left of “Main”, there is a ubiquiti airmax tab. This is where the AirMax mode is activated.

How does AirMAX polling work?

When the base station is turned on, it distributes time/data slots to all clients, which is why data transmission by each client occurs regardless of how busy the “environment” is.

AirMAX features a QoS scheduler that automatically identifies VoIP or Video packets in your traffic to give them the highest priority.

Also, a priority combination system is used (adding priority to a specific client). A higher priority level means more “slots” are allocated.

To set up AirMAX polling:

All you need to do is select the client priority level. That's all here (hopefully, at the AirMax base station, polling is also turned on).

ubiquiti airmax devices allow you to create “local” networks with the number of subscribers up to several hundred, and by then adding their number (“points” with lower priority), “old” users will not notice the difference.

More about polling technology

Let's consider the situation: data transmission in a point-to-point topology. The transmission speed here is equal to the channel capacity; there are no collisions between subscriber points.

In this mode, polling technology is not used.

Let's consider another situation - “common bus”

Before transmitting anything, the Wi-Fi subscriber will listen to the airwaves - is it “busy”? Only if the airwaves are free will our subscriber begin the transmission. While he is transmitting, all subscribers except him will be waiting.

This is called CSMA/CA technology, it seems to be very logical. Collisions cannot happen here. And all this is true, with only one caveat: subscribers, although they work with the database, must “hear” each other. Actually, this is how the 802.11 (Wi-Fi) protocol works.

The ubiquiti airmax protocol is designed for a different topology (station - many points). That is, one where not all subscribers hear each other. Here - key difference from Wi-Fi (and WiMax).

In the worst case, the subscriber hears only the base. She may be in this moment busy working (receiving data) from other subscribers. When the base is busy, the subscriber does not know. When accessing it, “collisions” will arise.

Note: The problem is called the "hidden nodes" problem. If, in reality, it does not arise, the physical layer can be considered a “common bus” and WiMAX can be used.

The only way out here is arbitration between users, initiated by the database. That is, the database decides which subscribers are working and who are waiting. The technology is called "polling".

Currently, such protocols are not standardized; any manufacturer can come up with and offer their own version. And the ubiquiti hardware, the reviews of which we trust, is not compatible with other implementations (which may also be no worse).

In AirMax, the base station's "time" is divided into "slots". Which are allocated to each user in a certain quantity (which is regulated by priority). The priority, in turn, can also change.

Antennas

In hardware, ubiquiti airmax - the protocol only works with dual-polarization antennas of the MIMO standard (2x2 MIMO).

These devices use 2 RF channels (as you can see, the input connector on the antenna has 2 plugs). The class of these antennas is presented by third-party companies:

Actually, the same devices are used in the WiMax protocol. Let us emphasize here: with a “star” topology (as opposed to a “common bus”), the antenna can be omnidirectional, but this is not necessary.

Analogues and competitors

The main competitor of Ubiquti Networks is Mikrotik. The equipment of this company is more expensive. The access sharing protocol also works. And in comparison with ubiquiti, reviews on Mikrotik will be no worse.

Here we cannot campaign for a specific company. The choice is made by those who intend to use the equipment in the future, building a local network. Keeping in mind that devices for different “polling networks” are not compatible.

The official website of Ubiquti Networks (in English) is located here:

http://www.ubnt.com/

AirMax® is a wireless broadband technology from Ubiquiti that provides increased level performance, throughput, range and scalability compared to other wireless networking technologies. Products supporting this technology have a throughput of over 450 Mbit/s. This is three times more than devices from other manufacturers of the same class. To understand whether it supports specific model this technology, you need to pay attention to its name. AirMax is supported if the article number contains the letter “M”.

Main advantages of AirMax

This unique technology, used by Ubiquiti developers in their products, created a real stir among specialists in the field of network equipment and immediately gained a strong position in the market high technology.

Let's find out why experts in creating a wireless network connection love it so much:

• up to 100 other stations supporting this technology can be connected to the AIRMAX base station;
• The time slot method increases the efficiency of airtime by eliminating the intersection of channels for data transmission;
• the QoS service package prioritizes traffic, transmitting data in the order automatically established after analyzing the criticality of applications (for example, audio and video files are transmitted first);
• hardware acceleration using silicon Ubiquiti technologies dramatically improves TDMA latency and increases scalability for the AirMax network;
• the absence of noticeable time delays in the transmission of applications sensitive to slowdowns, even for clients significantly distant from the base;
• the range of access points that support this technology is more than 1 km (subject to the installation of two access points in “bridge” mode).

Based on the above advantages, the Ubiquiti brand has extremely effectively implemented the technology for creating network access through so-called polling (operations that determine the queue for sending traffic through the base), when each of the devices connected to the network sends a request to the base, and only then, after waiting for the time set by the base, sends or receives a flow of information. The products of this brand, which provide polling, have actually become a breakthrough in the field of high technology - having a low cost, they are able to provide a network connection to subscribers located several kilometers from the base itself! Thus, Ubiquiti devices supporting AirMax technology are a cost-effective purchase that provides the most optimal conditions for creating wireless networks.

AirMax as one of the most advanced polling implementations

This technology is one of the most thoughtful polling options. In this case, such an algorithm of actions absolutely eliminates the occurrence of such collisions as the problem of a hidden node (arising in the presence of remote subscribers or complex environments with a lot of interference) or the problem of an unprotected node (arising in the presence of a neighboring transmitter and forcing one of the nodes to mistakenly wait). Moreover, AirMax technology allows you to individually control each channel: set either average performance for total number subscribers, or allocate personal bandwidth for each subscriber (depending on the type of data transmitted).

So what is the main difference between AirMax and WI-FI?

IEEE 802.11 technology is quite effective in creating network coverage within an apartment, office or enterprise. However, when implementing wireless network access over fairly large areas, subscribers using the usual set of 802.11 IEEE a/b/g/n/ac standards (in other words, WI-FI) often encounter the problem of the collisions described above - a hidden node and unprotected node.

In both situations, the subscriber does not receive information about the network operations of other subscribers, resulting in long-term downtime or ineffective access to the database (when one or more user devices trying to simultaneously send a request to the database). WI-FI developers have found partial solution This problem is solved by the RTS/CTS mechanism, which is optional and unfortunately has significant drawbacks. In case the volume transmitted packet is relatively small, the remaining subscribers do not receive the “wait” command and an intersection of channels is formed, as a result of which the contents of the packet are sent incorrectly. In addition, the use of this technology entails possible network congestion in the event that subscriber bandwidth is falsely blocked for transmission.

As for AirMax technology, these pitfalls are completely absent. The base itself determines which lane should be opened for sending information and assigns maximum bandwidth to each of them. Given this advantage, Ubiquiti models with AirMax technology will be the most efficient choice for customers looking to distribute network connection hundreds of meters. Devices compatible with this technology are able to select non-standard radio frequency ranges for operation (for example, 900 MHz, 3 GHz or 6 GHz), in addition to the familiar 2.4 GHz and 5 GHz, thereby eliminating the possibility of the channels of the created network crossing with an outsider. network equipment, mobile phones and microwave ovens. At the exit, clients experience seamless data transfer with a high level of network efficiency.

Devices that support AirMax technology

Trademark Ubiquiti has implemented this technology in the following devices.

Like many teenagers of the 1990s, who today overestimate seemingly familiar and understandable things, I am increasingly faced with the absurdity of my thinking back then. I don’t deny that this is a problem of age-related rethinking and living according to the principle of common sense, and that modern teenagers are also going through something similar, and that this article will not convince them in any way... But it’s worth a try. And let's start with loud statement that Nike Air is complete nonsense. I'm not trying to prove that Nike Air technology is useless, I want to argue that the technology itself is fundamentally absurd and is just a marketing ploy that allows the company, de jure and de facto, to sell air.

Gas-filled cushioning cells revolutionized the world of running shoes when they first appeared over 30 years ago. Nike advertising that promotes the idea that air-sealed air in sneakers will make you a great athlete doesn't make sense. You just need to pay attention to the shoes that professional runners wear.

Yes, it is impossible to reinvent the sneaker, and Nike already seems to have admitted this. What does the company do? It's just trying to convince fragile minds that Nike Air technology is more than just a "gimmick" based on the consumer reflexive "wow" effect.

But it was not always so...

Early years in Oregon

In 1964, Phil Knight, a former University of Oregon runner, and his former coach Bill Bowerman founded the company to provide the running community with access to the best shoes. They called it Blue Ribbon Sports (BRS), and very soon the company became a distributor for Onitsuka Tiger. In fact, Bowerman sold most of his shoes out of the trunk of his car.

Knight, who was finishing his MBA at Stanford, and Bowerman came to the conclusion that they needed to create something of their own, something more than a store on wheels. They “designed” new sneakers, which were already released by Onitsuka in 1969 under the name Tiger Cortez. And then he and Knight began collaborating with a Japanese factory, and their goal was to create their own line of sneakers. They called it Nike. And their first model was called Nike Cortez.

Onitsuka didn't realize that Bowerman had copied their design almost entirely until one of their employees visited the old BRS warehouse in Los Angeles. However, the court ruled that both companies could produce essentially the same sneakers. In reality, Knight and Bowerman were selling the same shoes to the same runners, only they replaced the Onitsuka logo with their own. A local student named Caroline Davidson designed the famous “snot” (in America it’s called a swoosh) for the brand, for which Nike paid her only $35. More than a decade later, Knight gave Davidson Golden ring in the form of a company symbol, encrusted with diamonds... and an envelope with Nike shares for her work.

This is where the story of lies, or as it is commonly called today, of the Nike marketing company began. Knight and Bowerman quickly realized that they didn't have to sell a unique product, but rather sell an idea. Public approval of athletes, slogans - all this became an integral part of the brand, which encouraged people to believe in the product (brand) itself, and not in its properties.

NASA and the birth of Nike Air

It's no surprise that Nike and NASA crossed paths in Nike's early years; at that time, almost every new invention related in one way or another to the Apollo space mission. And Nike Air was no exception.

Nike was ready to take off by the late 1970s. The company was wildly successful after receiving the endorsement of their new Waffle Trainer running shoe from long-distance runner Steve Prefontaine, for whom Bowerman designed the sole by pouring rubber into his wife's waffle iron. Then in 1978 Nike showed off something completely new called the "Air Tailwind".

Originally designed for the Honolulu Marathon, the Nike Air Tailwind included new technology, developed by former NASA engineer Frank Rudy. Rudy's innovations again emphasized an aeronautics technique called rubber blow molding. The technology, once used to create helmets for astronauts on the Apollo missions, later allowed Rudy to design a midsole in which he placed polyurethane cushions filled with dense gases.

In 1979, Rudy patented this design. The idea, as well as the branding strategy, was based on the assumption that using air would provide superior cushioning and that air cushions would not lose their properties after the first use. Nike Air was initially marketed only to elite runners, but then the strategy switched to anyone willing to spend $100 or more on a shoe.

At first, consumers had to trust Nike's technology to provide superior cushioning, since the Nike Air, for the average consumer, was nothing new, unlike the original Tailwind sneaker. In fact, the first mass-produced Nike Air had no new system depreciation. In this regard, Nike came up with a new demonstration gimmick.

Nike Air Max and profitable transparency

By the 1980s, the Air Force 1 and the original Air Jordan took the basketball world by storm, giving the company an image as a rebellious brand. This began after the NBA banned the original Air Jordans for color inconsistency. Lawsuits followed, but Jordan refused to take off his sneakers, and Nike essentially paid all his fines. But the company continued to update and push Nike Air technology to new levels.

Nike became a billionaire company in 1986 when it completed a major redesign of its line of air-cushioned shoes. The following year, the company released the Air Max 1, a sneaker that featured air cushioning in a small "window" at the heel.

A little reengineering has happened. What was a thin air cushion container was redesigned into something that squished and contained "visible air." There was a thick cushion in the center that provided the bulk of the cushioning. This was a marketing ploy, not a breakthrough in the industry, as the company claimed. Not only was the air visible, you could also poke the throttle pad and feel the intense recoil.

The Air Max shoes clearly demonstrated the technology without going to great lengths to explain how it worked. Essentially, it is just a polyurethane cushion filled with an inert gas. Simplicity became key to the overall design. Ultimately, the original Nike Air Max I, designed by legendary Air Max maestro Tinker Hatfield, created a formula that allowed Nike to make billions of dollars in its first decade.

“The shoe was breathable, flexible and fit perfectly, and the fact that it had an air cushion in the sole made it very different from other shoes of the time,” Hatfield said a couple of years ago when talking about the Air Max line. .

Nike's sneakers were sold not only as air-filled sneakers, but also as quite unique and personalized products, as each model came in a huge number of colors. Nike has been changing the shape and composition over the years, selling the public fake innovations that have appeared in each subsequent generation of Air Max sneakers. However, the principle of air cushioning providing comfort and development is ingrained in the company's marketing strategy.

Suddenly, sneakers were more than a mixture of synthetics and rubber that you strapped to your feet and used as a device that made you an athlete. Hatfield also claimed that the Air Max's design was inspired by the Pompidou Center in Paris, a nod to legendary architects Renzo Piano and Richard Rogers. Indeed, technology has made sneakers look futuristic.

Short family Air history Max and his descendants

In this article, I propose to focus on running shoes, since Nike Air technology was originally aimed at leading runners. It's also important to point out that Nike marketed the extra cushioning as something every runner needs. This assertion has become quite dubious in last years. Experts say shoe companies like Nike are to blame for this misconception.

The problem with the shoe industry as a whole is that everyone produces standardized shoes. Shoe manufacturing methods do not take into account the characteristics of each runner and do not meet their needs. And in doing so, Air Max's path of innovation boiled down to the great American ideal: bigger is better. This philosophy is clearly expressed in the now iconic Air Max commercials of the 1990s. Even the aesthetic of simple black text on a stark white background highlights this simple yet bold formula.

"[If you love] Air Max," the ad seems to say, "[You'll love] Even more Air Max."

The concept of "even more" has since developed in the most absurd way. The original Air Max of 1987 already boasted of the visibility of its technology, but in all subsequent models it was visibility, and not manufacturability, that became the main factor of promotion. In the Air Max 90, the air cushion has become a little larger and the window for admiring the “technology” has become even larger. The same goes for the Air Max IV, also known as the Air Max BW. The colloquial "BW" stands for "Big Window" as it is...really big.

From then on, everything became more and more absurd. In 1991, the same year as the Air Max BW, Nike introduced the Air Max 180, which featured air movement from the heel to the foot.

Then came the Air Max 93 with visible air, in which the air cushion was completely “naked” in the heel. They look very cool, and what more does an ordinary teenager need.

What does Nike say about Air Max technology? Does the cushion really make athletes run faster and jump higher? You will be surprised, but Nike has never claimed this.

Instead, she created a vulgar commercial star out of Quincy Watts, an American runner who had just won two gold medals at the 1992 Olympics in Barcelona. Of course, he wasn't wearing Air Max 93s when he won. But who would pay attention to such a small thing?

Nike used star athletes to promote "new technologies" without exactly explaining their benefits. The slogans in advertising have always been clear and unambiguous: “the more air, the better the shoes.” And visible air looks even cooler. Super cushioning isn't always such a good thing either.

Nike has made progress with the Air Max 95, not only in terms of technology but also in terms of design. Shoe designer Sergio Lozano made a dramatic departure from the simplicity of Hatfield's previously designed sneakers, resulting in the sneakers becoming even weirder. The Air Max 95 features a narrow air window in the toe box, as well as a new convex window in the heel. The new original combination of gray and neon green was reminiscent of the popular thriller “E.T.

In addition to the bold design, Air Max technology made the shoe a real fashion statement. However, no one paid attention to the fact that during the 1996 Summer Olympics in Atlanta, not a single athlete used such sneakers. Nike-sponsored runner Michael Johnson wore custom gold spikes that had virtually no cushioning at all.

Maximum Air Max

By the late 1990s, trends in the athletic shoe industry were turning more toward the sensible rather than the sensational. New Balance and Asics emphasized quality and customization while still providing decent cushioning. Nike, on the other hand, has dived headfirst into Air Max technology.

After the Air Max 95 proved that sealed air cushions weren't just in the heel of the shoe, Nike gradually began filling the midsole with air. The Air Max 97 featured a visible air window that spanned the entire length of the sole.

Then Nike, with Air Max Plus, came up with something called Tuned Air - different types of pressure in various parts shoes The trick of Tuned Air is to add mechanical elements to shoes that provide required quantity support where needed. There was also an entire line of shoes featuring Zoom Air technology, which Nike said "turns the pressure of each step into responsive energy for the next." By the time 2006 rolled around, Nike did the inevitable and released the Air Max 360, a shoe with an air window that spanned the entire sole, from heel to toe.

So we've gone from "Air Max" and "More Air Max" to "Literally maximum quantity Air Max that can fit in a shoe." Here's the whole development story from 1987 to 2015.

If Nike's marketing teams were telling the truth, these shoes would literally make athletes fly. If Nike's desire to improve technology to turn athletes into champions was sincere, we should have seen Olympians soaring above the crowd in their magical Air Max. But that did not happen.

In fact, just the opposite is true.

Nike calls its own products bullshit

A few years after the release of the Air Max 360, a pair of Nike sales representatives visited sponsored athletes at Stanford University to find out which latest models their sneakers they prefer. Stanford head coach Vin Lananna pleased them with very interesting news: his athletes showed top scores when we practiced barefoot.

This situation is well described in the book Born to Run by Christopher McDougle, who preferred to run barefoot. The author has spoken with legendary runners from around the world, including the Tarahumara of Mexico, who have run hundreds of kilometers while wearing rags and thin leather sandals. After talking with experts on the human body, McDougle found that the 20th century fad for super cozy shoes actually correlated with an increase in injuries.

"A large number of"foot and knee injuries that currently plague runners are caused by athletes wearing shoes that actually make their feet weaker, cause ankle sprains, and create knee problems," says Dr. Daniel Lieberman, a biology professor at Harvard. In 1972, when modern athletic shoes were invented, athletes ran in shoes with very thin soles, which resulted in strong legs and very few knee injuries."

Due to the large number of similar reports, barefoot running, as well as shoes that simulate this effect, are taking the world by storm today. After America's top athletes told Nike they were wasting their time on useless properties, Nike decided to create new line sneakers that emphasized everything that Air Max didn't have.

So Nike did their own research and released new model: Nike Free. These are shoes with minimal cushioning and maximum flexibility. (It was as if all the air had just been sucked out of the Air Max 360.) Additionally, the design of the new sneakers included a numerical system to indicate the degree of cushioning. The Nike Free 3.0 was best suited for those who prefer to run barefoot, while the Nike Free 7.0 (which is no longer available) offered more cushioning. Now this is Nike Free 5.0 V6.

"We found a huge number of people around the world who still run barefoot, and found that during the push and landing, their feet have more freedom to move," said Jeff Pisciotta, a senior researcher at Nike's McDougle Science Laboratory. "Their legs move through a huge amount of motion, which means they experience less pronation and the pressure is distributed over a larger area."

The first Nike Free sneaker came out in 2005, and technology became one of the cornerstones of the Nike line. Nike designers have finally admitted that the outsole is "just a piece of hard foam."

Since the advent of barefoot running, a ton of research has emerged claiming that too little cushioning is also bad, causing most runners to revert to simple, comfortable shoes.

So we have to wonder, will the air cushion pendulum continue to swing back and forth? The revolutionary idea of ​​putting an inert gas into polyurethane cushions that soften the impact of every step still makes sense for some runners. Nike Free makes sense for other athletes. In the end, it all really depends on your foot and your gait. You want sneakers that are perfect for you, no matter what's in fashion.

Today there is simply a sea of ​​Nike sneaker fans in the world, for whom the company’s technologies have absolutely nothing to do with sports. Their choice is just a tribute to fashion. This is what can be called the main success of the brand. People buy sneakers in huge quantities various reasons, and Nike re-releases the old "right" and "wrong" Air Max models over and over again. The company is also reincorporating classic Air Max technology into new designs and even adding Air Max technology to the Nike Free midsole.

As a result, Nike designers' use of technology is similar to the fashion industry's approach to certain recurring trends. They come and go without much meaning or reason. Constantly emerging technologies Nike shoes have quite a bit of science behind them. But it seems that this does not matter to fans of the brand.

The material was prepared based on an article from the site gizmodo.com - for readers of the site site

P.S. My name is Alexander. This is my personal, independent project. I am very glad if you liked the article. Want to help the site? Just look at the advertisement below for what you were recently looking for.

Copyright site © - This news belongs to the site, and is intellectual property blog is protected by copyright law and may not be used anywhere without active link to the source. Read more - "about Authorship"

Is this what you were looking for? Perhaps this is something you couldn’t find for so long?

Increasingly, from the mouths of novice wireless Internet operators planning to use company equipment in their networks (for example,) questions are being asked about what is AirMax. Because this protocol is a closed development, information about which can only be disclosed within the company, then a description of the details and particulars in the implementation of AirMax is practically inaccessible. However, the general principle of operation is quite clear.

To briefly describe AirMax technology, it is a special in-house protocol for wireless data transmission, developed by Ubiquti Networks. Many users noticed that the name of the new protocol is similar to WiMAX, which cannot be called an accident, but rather a cunning marketing ploy. However, AirMax relates to this standard very indirectly.

The essence of the technology is that there is a temporary division of packet transmission for each subscriber. Normal data transmission over Wi-Fi occurs as follows: the station on the subscriber’s side “listens” to the air, determining whether the channel is busy, and if it is free, it sends a packet. This technology is far from perfect and is unable to provide high-quality communication.

AirMax solves this problem by providing each subscriber with a specific time slot for transmitting/receiving data. As a result, there is no need to listen to the broadcast, and delays disappear.

The second feature of the technology is the ability to identify clients with “heavy” traffic (VoIP/Video) and give them priority.

AirMax advantages

Using the AirMax protocol provides several important advantages.

First is scalability. wireless network. Using AirMax will prevent a decrease in channel quality when a large number of clients use it simultaneously. If in an 802.11 network implemented using Wi-Fi technology, it is recommended to simultaneously connect no more than 20 users, then using AirMax technology up to 120 clients can work at once.

This achievement became possible thanks to a change in the principle of information transfer at the MAC level. IN Wi-Fi networks The degree of channel occupancy can be determined using the carrier availability information base. AirMax uses the technology of polling network clients with a base (polling). This technology made it possible to solve the problem of “hidden nodes” - when two network subscribers simultaneously try to send a signal, because when listening to the broadcast, they “do not hear” each other due to distance or other factors.

Secondly, the use of AirMax technology allows minimize latency for voice and video transmission. Algorithms for polling network clients do possible definition those clients that transmit latency-sensitive video and voice, and give them priority over others.

Thirdly, high data transfer rates have been achieved. This achievement cannot be attributed to the company’s merits, since this became possible thanks to the use of technology, which makes it possible to increase the speed of information transfer at the physical level. The unique development of Ubiquti Networks is cross-polarization antennas, whose characteristics are as close as possible to antennas in the operator segment, the cost of which is much higher than non-professional ones. These antennas have undergone special tests for compatibility with Ubiquti Networks devices that support AirMax. This is done to optimize the characteristics of radio channels.

Devices that support AirMax technology

As we have already said, this protocol is a proprietary development of Ubiquti Networks. This means that devices from other manufacturers will not be able to work with this protocol. However, like the older equipment of the company itself.

Standard series wireless equipment, which are produced with support for AirMax technology, are marked in the name - M.