Thursday, June 9, 2011

Performing Passive Site Surveys with AirMagnet Survey Pro and Ekahau Site Survey

I've had the good fortune to receive a fully functioning (albeit limited to 90 days) license for the Ekahau Site Survey application. This is thanks to @Etherealmind meeting up with Jussi Kiviniemi from Ekahau at Interop. Jussi was in the Metageek booth at Interop to help showcase the Ekahau software suite and how it has been integrated to work with Metageek software/hardware. 

Thanks also to @SFoskett for recording the great video demonstration on the partnering between Ekahau & Metageek.

Starting off with what I know (because it is easier to explain what you already understand) I made a little video showing how I setup a map and perform a passive site survey of an existing wireless deployment. Naturally I'm expecting a similar functionality from the Ekahau Site Survey application. The only experience I have with the Ekahau application dates back to 2005 when I saw it used to do a passive survey of the hospital where I worked. I was not too impressed with the color charts used to represent the 'heatmap' of RF coverage. I thought that the color maps Ekahau used to show different areas of RF signal strength were not easy to understand, and showed the coverage with strange trapezoidal coverage boundaries.

I had to load a different driver for the Orinoco Proxim 8494 USB wireless card, but the Ekahau application had the drive it required as part of the installer. The installation was quick and painless, and then I had to set about figuring out an new site survey application. Starting a survey was pretty straight forward, but I did see that the survey data was collected quicker once I upped the 'wait time on channel' setting to scan quicker. There was a broadcasted SSID, so I was able to decrease the scan time and get survey data quicker as a result.

The things I don't know how to do with the Ekahau Site Survey application:
Show the SSIDs detected on the floor plan one SSID at a time
Show just the 802.11a or 802.11b/g coverage on the floor for each separate access point detected
Show only one data collection sample at a time. When I used the select/deselect options, the coverage map still showed on the floor plan. This might be because I still had the dropdown set to show the signal strength, but I can't be sure.

I did find the images from the site survey data from back in 2005. You can see what I was referring to regarding the coverage areas showing as large trapezoids. I think this must have been due to the team surveying not setting the granularity of their displayed data. Also I noticed that they didn't enter many of the patient rooms in order to gather RF data. When I'm doing a passive survey in a hospital, the only rooms I don't enter are the ones with the Isolation signage on the door.

1 comment:

  1. Hi Jennifer, thanks for your insightful notes. I find your blog quite informative. Let me ask you your strategy for performing a survey for a client when an existing WLAN infrastructure already exists? You can't exactly stomp all over their network and you need to collect valid data at the same time. Do you ask to disable the existing RF during the process?
    Thanks in advance