Planning and maintaining Wi-Fi networks

On the crest of a radio wave

It would seem that after ratification of the 802.11n standard in the Wi-Fi industry, a relative lull should occur: specifications are approved, device certification is in full swing, corporate and home markets are saturated with hundreds of wireless devices, offices are massively bidding farewell to a twisted pair Mature wireless technology, and all these technological joys, tirelessly, provide Chinese workers. But the calm, of course, did not come. In the market there is a severe struggle for the hearts and wallets of IT departments.

The fact that Wi-Fi is quite ready to replace the twisted pair in most situations is clear to all professionals working in the market. Of course, there are still people who are suspicious of Wi-Fi, because there were quite a few reasons for this in the past: 802.11 a / b / g was slow, the WEP broke easily, the hardware hung, the coverage radius was small. The list can be continued, but today for all the serious problems of the "early" Wi-Fi solution found. The last director or official who will cling to the wired network will die out in about ten years, but it is already clear that the equipment 802.11n (and subsequent standards) won the wire. By the way, not least in this “guilty” and senior officials, among whom now it has become fashionable to pace with iPads. Those who have eyes will see that a signalman with a coil does not run behind them to provide secret government communication, and the quick video on the screen suggests that the packets are running over Wi-Fi, and not dead even in the capital 3G. Beyond the iPads, no doubt, there will be a wave of already normal, multi-tasking tablets that can be used for business and other reasonable purposes, and which will add to the already existing huge army of laptops, smartphones, VoIP phones and desktops.

The smart hardware and software provides all this economy with communications, and it is in the development of such hardware and software that the main competitive struggle of leading manufacturers is underway. The 802.11n standard is very extensive and diverse, it allows you to create very interesting engineering solutions that today are far from exhausted all the possibilities offered by the standard. Let's make a reservation that we are talking about solutions for the corporate market. Home Wi-Fi infrastructure is created on the basis of fairly simple and cheap access points at the cost of a couple of thousand rubles, which provide quite acceptable quality. There are even a number of enthusiasts who are trying to build corporate Wi-Fi networks based on such home access points (and it even sometimes works if there are only a couple of people in the office), but this is rather a marginal trend.
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Meanwhile, corporate solutions today offer a lot of attractive innovations (of course, at higher prices). From an engineering point of view, these are very interesting technologies, which are worth reading in more detail if you have not done so far. And we will run through them very briefly to whet our appetite.

Cisco integrates spectrum analyzers into the access points, which automatically determine the source of interference, its type and switch the equipment to a channel that is clear of interference. Until now, for analyzing the spectrum, we used separate devices (ranging in size from a flash drive down to a brick) with the appropriate software, which allowed the engineer to visualize a certain range of the spectrum on a computer screen and, thus, estimate the band load, see the interference, etc.



Cisco has taken a logical step forward: the Spectrum Expert analyzer has become part of the access point (starting with the 3500 series). The analyzer works in both Wi-Fi bands (2.4 and 5 GHz), has a high resolution (10 kHz) and uses an intelligent response system to sources of interference. In addition, unlike the engineer, he works constantly. How do you like this trick: if the rest room every day at one o'clock includes a microwave, which “clogs” channel 2, the access point will learn to switch to channel 11 every day at this time.

Ruckus lures BeamFlex with smart and compact arrays of antennas, providing unparalleled range and quality coverage.



Such a compact array can change the directivity pattern in real time, and the diagram adapts to each client's access point each time it is necessary to transfer packets to the client. Thus, the access point avoids interference and reduces noise for other devices and networks and increases performance and coverage up to three times.

Aerohive promotes trendy clouds and Wi-Fi architecture without controllers, with centralized management of the entire infrastructure. And here the clouds, you ask. Everything is very simple: the Wi-Fi network management system is now located in the cloud, supported by Aerohive. Those. All concerns about installing and operating the server and the software managing the network are assumed by the iron manufacturer. You just need to connect the access point to the network. They will find the cloud on the Internet themselves, register and be ready to manage from the central "cloud" console, which you can access via any browser. As for the architecture without controllers ( Cooperative Control Architecture ), it will remove the bottlenecks characteristic of traditional Wi-Fi networks with controllers. Aerohive access points are themselves controllers that organize themselves into “cells”.

Atheros , the leading chipset supplier for access points that Qualcomm recently bought, is starting to deliver chipsets with three MIMO streams that will provide transfer speeds up to 450 Mbps. These and many other equipment manufacturers are also actively working on transmit beamforming , a technology that allows you to “focus” the signal on the right place in space without “spraying” it in places where there are currently no clients.

Why do you need TamoGraph

All this iron splendor will work as it should only under one condition: the network must be properly planned, deployed, and tested. Your equipment manufacturer and manufacturer will break the harsh reality into smithereens if, for example, you do not take into account the fact that in the next office there is a 200-milnyat access point on the 6th channel with a dipole antenna, which clogs all the available radio -spectrum with your signal. To avoid errors, it is necessary to conduct a network inspection before and after deployment.

Inspection, i.e. The collection, visualization and analysis of the characteristics of the Wi-Fi network is carried out using special software, such as TamoGraph Site Survey , which is produced by our company Tamosoft . We have two serious competitors from AirMagnet and Ekahau , and there are several simpler freeware programs. Further examples will be based on TamoGraph as a more familiar and familiar program. In addition, as far as I know, only our company is actively promoting this product in Russia, has released a fully localized Russian version and accepts payment in a convenient form (Softkey, WebMoney, etc.), while AirMagnet and Ekahau are not oriented towards Russia.



Having installed TamoGraph on a laptop and having imported a plan of a room or terrain, the engineer bypasses the room, marking his current position on the plan (or even going around an open space, say campus, on a bicycle, while the current position can be automatically marked by a GPS receiver).



After collecting data, the program can build a lot of useful visualizations that allow you to find problems that can affect network performance and coverage: signal levels in the 2.4 and 5 GHz bands, interference from other networks, expected data transfer rates, compliance with specified requirements, etc. . By documenting the result with a report that is easily generated directly in the program, you can make network adjustments based on the data: change frequencies, change antenna types, move, remove or add access points, and so on.



Summing up, we can say that today, building a network on equipment technology leaders and analyzing it with high-quality software tools, you will not only get excellent performance and security, but also save money both at the equipment procurement stage and at the network operation stage. If you have not started building a Wi-Fi network - start. And of course, do not neglect the specialized, neutral in relation to the manufacturers of equipment and software, training and certification, such as CWNP . Your training in the field of Wi-Fi is the key to success.