Tuesday, February 20, 2018

Evolution into wireless - How not to do it today


In the beginning when I first started designing WiFi network wireless was always considered more of a "toy" or "convenience" item.  My 1st real deployment was for a hospital when they were converting over to electronic medical records in their inpatient areas.  I had the usual discussions we have today with key stake holders and asked them the crystal ball questions to determine not just the immediate needs but also try to design for at least the next few years.  In answer to this question I was told very specifically by hospital leadership that they can't imagine any more then 150 wireless clients ever on this wireless network and that is what I should design the network to support.  This was a 500 bed 7 story hospital.  Back then it was not uncommon to simply line up the AP's in the hallway...mainly because they did not allow AP's in the patient rooms.

So I determined typical AP locations in the hallway in reference to the patient rooms on either side of the hallway to get a few "rules of thumb".  Back then I had no tools or survey software to work with but I did have the "bars" on the windows network desktop and continuous pings.

To deploy I marked up the floor plans of the hospital and had the cable and network staff start deploying the AP's as I directed.  Making way to many assumptions and being WAY too conservative on the number of AP's and WAY to generous on the output power of the AP's....did I mention this was 802.11b radios?.

Please note....when YOU are the only wireless client on a wireless network and you do coverage testing the wireless coverage is amazingly great!  This was the first time I learned that coverage is NOT everything. 

Also note I BEGGED to have some kind of soft roll out of the wireless carts for the nurses...maybe a phased approach?.....maybe just get the devices deployed to the floors before go live.....No cooperation on any of this!

Go live day(weekend) comes and the PC group rolls out all these large battery powered carts to the staff to now start using this software that they were trained on a few months ago.

Overall this 1st roll out was not horrible...considering how much was left up to chance and at the time I had no idea what I was doing....At least to that scale.


As time rolled forward they started to add more and more devices.....without communicating to network that this was happening.  Complaints roll in.....I got better and learning and recognizing the issues.....reading a LOT.....Learned about CCI (something I already knew about in my previous career in radio systems).  High utilization....Using smaller cells at lower power....beacon rates etc.....


What I love about WiFI has been the never ending learning involved.  This always has kept it interesting to me.