Air Magnet The Wi-Fi Engineer’s Tool Belt

The second vendor I very much wanted to blog about from Wireless Tech Field Day is Air Magnet. As I gained more knowledge in deploying wireless solutions and progressed beyond simply following the setup instructions my colleagues gave me to implement specific features and functionality I became aware that I needed a larger knowledge base to learn from. My boss at the time recommended using Air Magnet Wi-Fi- Analyzer as it not only was useful in troubleshooting the various problems that came up, but it also had quite detailed explanations and help in its ‘AirWISE’ section of the nature of specific problems it saw and the solutions for those problems. Before I began to study the CWNP program’s materials this gave me some insight and practical knowledge I was lacking. So I have a long history with Air Magnet and although they generously gave me a copy of Air Magnet Spectrum XT at the Field Day it doesn’t change my opinion of their products. I should point out that there was no expectation implied or otherwise in their giving me the XT that I would blog about it or even do anything with it than enjoy it for my own use.

So what is the basic parts of a WLAN professional’s ‘tool belt’? I would say there is several parts to answer that question. The very first thing you are asked to do is to design or plan the WLAN you are going to deploy. In much the same way a builder needs plans to build a house, the basic plan that is needed to deploy a WLAN is the site survey. As 802.11 operates in a part of the radio spectrum that is shared by not only many other types of radio equipment but also other WLAN equipment then you need to have some way, some set of tools, to both see what the spectrum usage currently is and to make a plan to deploy your access points so they will function correctly. You also need to be able to verify after the deployment that things are working correctly and as the RF environment can dynamically change from day to day and hour to hour, you need also a way of troubleshooting both at a spectrum level and at the level of the 802.11 protocol itself what is going on.

Air Magnet’s singular focus has been to make a set of tools that cover all of the above needs for the WLAN professional. Bruce Hubbert, Principal Systems Engineer, covered the first part with Air Magnet Survey at Wireless Tech Field Day. I have been using this tool for several years and still was amazed to see it had functions and features that I didn’t know where there that came up as part of the presentation. Survey gives you the ability to both plan and to verify after the deployment what the WLAN signal will look like. There are often ‘free’ wireless vendor tools for planning that are offered as a part of the purchase of their access points. Almost every one of these I have looked at suffers from the same problem, you will see almost immediately that the APs placed have ‘circles’ of signal surrounding them as if there is nothing blocking or altering their path. This is in almost every case simply not how the signal strength will look once you deploy it and gives you a false sense of how much coverage you can get from the APs. At the very least your users will alter the signal! My opinion of the free tools is you get what you pay for and to me they are pretty much useless for planning purposes. Survey was recently updated to include the ability to use multiple adapters during a survey. Up to two WLAN cards plus a Spectrum Analysis card like the Spectrum XT. This means that you can choose to do, for example, both a passive and active (associated to the WLAN) survey at the same time which gives you a great deal of insight into verifying your deployment.

Air Magnet’s Wi-Fi Analyzer was next up. It also has added the ability to support up to three cards. I mainly use this program for troubleshooting when a currently deployed WLAN is not functioning properly. It has an overall ‘dashboard’ to give you an overview of the current state of the WLAN and then several screens for looking at the list of APs seem and what their signal strength is. I mainly use this to get a good overview of how busy the environment is in the area. I’m sure many of you will be familiar with this basic functionality from tools such as Netstumbler which give similar information, but Wi-Fi Analyzer goes to a much deeper level. It has several other screens so you can focus down on an individual channel, what the RF interference is like, how busy the channel is and much more. My favorite piece however, is the expert analysis given by ‘AirWISE’ which gives explanations of problems seen in the WLAN and suggestions for resolving them. Wi-Fi Analyzer, true to its name, gives you analysis all the way down to the packet level in that you can see the packets as the flow across the network and capture them to save to examine more closely later. Honestly there are too many pieces to this program to tell you about in one blog post but I would sum it up as being as simple or as complicated as you need to troubleshoot your WLAN.

Being able to troubleshoot the WLAN at a packet level isn’t enough, unfortunately. Network engineers almost never these days have to routinely run tests on cables, the physical layer, in order to get the network up. As wireless professionals we need this because of the many other devices sharing the physical spectrum we use. Air Magnet’s Spectrum XT fills this need and very capably. Before this card was released Air Magnet sold a spectrum analysis card made by Cognio which they rebranded. They had some ideas for further extending the capabilities of this product and when Cisco acquired them approached them with their ideas. Cisco, unfortunately was not receptive to this as they were focused on using the Cognio technology in their CleanAir access points. This lead to the development of the Spectrum XT. Spectrum XT is a young product as yet and so has the basic feature set. It has the ability to produce the functions that you would want to see at this level in that it will show you the Real Time FFT charts, Spectrogram and Spectrum Density charts. It can also use a WLAN adapter to provide the 802.11 information on what the signal from access points looks like as well.

The last need is constant monitoring and for this Air Magnet Enterprise is the tool for this. Jesse Frankel presented the Enterprise product to Wireless Tech Field Day and went over in detail what it is capable of. For me, this is a product that I have been aware of but for some reason just not sat down and taken a good look at it. I did see, however, that Air Magnet is continuing to innovate by adding features such as dynamic signature updates to the product. The basic operation of AM Enterprise is that you distribute an overlay of sensors (specialized access points for monitoring) in your network in addition to your APs. These sensors send back information to the AM Enterprise server which collects and does all the heavy lifting of examining the information. I have encouraged people for some time to implement for both security and monitoring purposes on their network some kind of overlay monitoring type system such as this. To me, at an enterprise level you ask yourself first ‘how do I get users access to wireless’ and deploy your APs. Next you want to keep it running so they don’t complain and for this you need some kind of monitoring system. This is where I think the value of AM Enterprise comes in, it not only gives you proactive security monitoring but also enables spectrum analysis and dynamic updates.

A good WLAN engineer always has several tools in his ‘belt’ to deal with various problems that crop up in planning, designing, building and troubleshooting WLANs. Air Magnet, which is now part of Fluke Networks, excels at producing tools that are able to make sense of some quite thorny problems in the daily life of the WLAN engineer. They have been at this for several years now and are regarded by almost every wireless professional I know as being high quality tools made with an in depth knowledge of how RF and 802.11 works yet bringing that depth of knowledge to us all in an accessible way. I made the decision several years ago when researching a standard set of tools for the WLAN engineers at my company to use Air Magnet Survey for on site verification and surveys, Air Magnet Wi-Fi Analyzer for troubleshooting and Air Magnet Spectrum XT for Spectrum Analysis. I highly recommend any one of these for use in these tasks at your place of business.

I was not very aware before this trip of the effect that their acquisition by Fluke would have on Air Magnet, but now that I have seen that this in reality is a melding of two companies with a very similar vision, one in the wired sphere and one in the wireless, I am all for it. The vision of using Fluke’s Air Check tool for junior network or desktop troubleshooting folks and letting the above tools become the professional set of tools makes total sense to me. I actually wanted an Air Check for myself, (but it was not to be) as I saw immediately how useful it could be in many situations. Adding to this Air Magnet Enterprise gives the network admin visibility and monitoring over the entire WLAN with dynamic security updates. This hits every level for the WLAN professional and is a powerful set of tools to make sure your WLAN is functioning like a well built house.

source: wifikiwi.com