Outdoor WiFi mesh topology vs. repeaters

Question

Here's the current configuration in our organization (which I believe is incorrect):

We have a number of Cisco 1500 series AP's (22 in total), that are mounted outdoors to provide seamless WiFi coverage over a large area. Each AP however has its own physical ethernet connection back to the WLC (All the AP's are marked as Root AP's). They are all broadcasting the same SSID. We have tried to stagger the channel selection but because there are only three non-overlapping channels to choose from, and in some areas the density of AP's is quite high, there is multiple places of channel interference. With this configuration we experience 100-150 disconnects from clients every day. (Our clients are mobile so they move throughout the coverage area constantly).

My idea is to switch the AP's to the same channel thereby forming a wireless mesh, use the built in functionality of the 1500 series to use 802.11a as the backhaul, designate one or two AP's as root AP's and wire them back to the WLC. Thereby forming a WiFi mesh, which if I'm not mistaken is the point of the 1500 series in the first place!

I am however completely new at WiFi networks and wondering if I am simply mistaken in what I believe my proposed changes will enable, or if there is a better way to tackle the WiFi topology.

Answer 1

You have too many AP's! If you are receiving that many disconnects (I assume from barcode scanners like, Datalogic Falcons) then you are doing something very wrong with your AP placement.

What you need to do is trim some AP's and add antenna to each of the remaining AP's to increase the signal range instead of adding more AP's. More is not better with access points because you're going to confuse the scanner guns as they have -db threshold for when they will roam. I think whats happening is as signal strength fluctuates (which it naturally does) the guns keep jumping from channel to channel trying to stay on the Access Point with the best signal strength/quality. The guns/pcs will keep track of what AP they are connected to via MAC address, so adding antenna increase the signal strength without increasing the number of actual AP's that are in the area. Keep in mind, and this is VERY important, that when you add antenna there will be two per AP and these two need to have line of sight with each other to be effective. I have seen professional installers mess that up.

Another thing you should be aware of is meshing your AP's will cause latency and quality issues as you add hops. This may cause an issue if your software makes use of a chatty TCP protocol (so check how latent aware you software is first). Meshing your AP's is good if you can't get a wired connection to a location or for fail over. In this case I don't see a mesh topology helping you out... Not to mention your root AP's may bottleneck.