Numbers

Several weeks ago I received an inquiry from an industry magazine editor regarding my observations of wireless local area network clients that operate on the 2.4GHz band versus the 5.8GHz band.  The editor commented that he was working up an article, because he had heard several people comment about the struggles associated with the amount of congestion on the lower, 2.4Ghz, band.  In previous email exchanges with this editor, I too had commented that because of decisions by wifi device manufactures, my team had to deal with the limitations associated with the 2.4GHz band.

When I received the inquiry, my first inclination was to validate my own assumptions.  So I chose to pull some numbers.  Thankfully, I had already initiated a process where I was pulling metrics from our wireless network system to get a better sense of how the institutions system was being utilized.  This process proved to be valuable in responding to the editors request for comment.  With quantified data, I could offer an informed opinion and then provide some data points that illustrate that opinion.

The article came out earlier this week, and then was picked up by Slashdot.  At this point I started getting emails from colleagues who saw the Slashdot excerpt.  Curious, I checked out the Slashdot site and started reading the comments associated with the excerpt.  It struck me as odd to see the number of folks who were questioning the data I had referenced.  Some challenged that based on the number of students enrolled at the institution, the numbers were inflated.  Others obviously put pen to paper, and determined that there were errors in the arithmetic.

I know when I see numbers flying off the page or a screen, I too question their validity.  Understanding the methodology and/or context provides a deeper meaning.    One comment from the Slashdot suggested that based on the number of connections sited, the enrollment of the university sited on the website, and making an erroneous assumption of the number of faculty and staff, that the math works out to 47 connection per user per day.  Unfortunately it isn’t that simple.  My own numbers indicated we see 6,100 unique MAC addresses connecting to our wireless a day.  Because of the characteristics differences between wifi clients, we see that laptops account for 4% of the daily connections while iPhones and iPod Touches account for 51% of the daily connections.  My own opinion this speaks to the functionality of these different types of devices.  A laptop connects when you open he clam shell and stays connected until you close the clam shell.  Typically these connections are sustain for much longer than a mobile device, because with a mobile device you pull it out and it connects to wireless as you check your email, facebook, calender, etc.  The duration of this activity is only sustained for a couple of minutes, and then the mobile device is shuffled into a pocket, holster, etc.

For me the numbers are important.  It provides me the confidence to talk about the topic of wireless network connectivity or more specifically the challenges of mobile connectivity.  It enables me to provide illustrations and challenges to be think through the rational for why we are seeing certain patterns.  Numbers by themselves may be informative, but grasping the story the numbers tell, in my opinion is where the real strength lies.