An introduction to wireless for uneducated users. For installations into small environments…
I recently came into a situation where I realized that there were a lot of small office deployments happening at another office. The engineers at that office had no formal training in wireless and barely knew there was a 2.4 and 5Ghz range. This blog is directed towards training brand new users on deploying wireless into small office situations with minimal formal education. (As in wireless training…not…high schoolers) -Also as cheaply as possible using tools they already have access to.
*This is by no means training for wireless experts or a how-to for designing enterprise environments. This is merely a write-up with the premise of “Something is better than nothing!” As most of us wireless engineers know, these are the complete basics of a decent wireless network, and tuning these parameters to the best of our ability can do loads for a crappy environment.
The first step in setting up a halfway decent wireless environment is knowing what could cause a bad environment. Here are the main educational bullet points for creating a general access network that should work:
- Channels. Each AP needs to be on a different channel. There are 25 channels to choose from in 5Ghz, and three in 2.4: 1, 6, and 11. This is because of interference. Since wireless is a shared medium -like a walkie talkie, we need to keep this separation in order to have proper communication.
- Channel Widths. In 80% of the environments, 20Mhz is going to be the channel width you want to use. As stated in the previous bullet, interference is again the reasoning behind this. Channels can be bonded at 20, 40, 80, and 160Mhz. I mentioned that 5Ghz had 25 channels. At 40Mhz, that is reduced to 12; 80Mhz -6; and 160Mhz -2. 40Mhz can be used occasional in certain remote offices but most of the time, neighbors ruin that for us.
- NEVER use 80 or 160Mhz channels in business environments. There are rare occasions where you could get away with it, but in general, just don’t.
- You will probably have to change all of these settings. AP marketing departments have apparently talked engineering and product managers to make this the default setting with every single vendor I’ve ever worked with. It’s stupid, but good to know about.
- Power. For the past 20 years or so, wifi has been coddled like it is this little Tweety bird. Engineers that haven’t been educated in wireless think its so small and innocent. That it needs help to get through walls. It needs to be petted and held like a little kitten. THIS IS FALSE. Wi-Fi is a Tasmanian devil. If you don’t control it by reducing power and controlling it with walls and antennas, it will wreak havoc on your environment faster than a monkey with a pile of dog squeeze.
- Signal. Signal is of course the most popular if wifi lingo. This is the strength of wireless network according to the client devices. You can measure strength with all kinds of programs but the best measurement of strength is going to come from the end-user device. Every device is different (even if its the same model) and no matter what your professional testing computer says, if the client has crappy signal, it’s going to have crappy performance. Statistics are useless if the end-user can’t connect!
Now that we’ve got a little guide of what to look for, how do we look at it? The tool you’ll be looking for is called a Wi-Fi network discovery tool. Depending on the vendor, most of these programs will tell you the SSID, the channel, signal strength, and sometimes the channel width of all the SSIDs it can hear. You’ll be using these tools to figure out what RF configuration, and where your APs should be placed. Why are you using a discovery tool? Because most of the time they are free!
Ideally with this information and a couple of tools you would be able to do some basic tests and give the customer a decent wireless environment. This can be accomplished by using a laptop, tablet, phone, or anything they can use the following tools.
Choosing an access point for a small office environment should be fairly easy…as long as you have a good budget for it. Will a Linksys from Walmart work? IT DEPENDS! Do you sit at home alone in your office and work on your laptop, phone, and tablet? Then, yes, the Linksys should be fine. Check a couple different home routers at your local store or Amazon and check reviews at different technology suppliers as well. NewEgg, Microcenter, Frys, and Amazon all have reviews. While it’s always good to look at reviews, you have to take them with a grain of salt as well. Some people just don’t know what they are doing. When their deployment strategy doesn’t work, they blame it on the device and move along to the next one. For a small business that is going to support multiple devices with multiple employees, I’d suggest upgrading your product samples to a SMB grade access point or router. Ubiquiti has a great selection of APs that perform very well for smaller environments. You could also check out some Aruba or Cisco APs that are designed to work without a controller.
Where does this thing go?!
Typically these should go as close to the location that wifi will be used as possible. Sometimes that isn’t possible, but there are a couple best practices that will help.
- The AP should always be placed in the recommended orientation. either hung on the ceiling or wall, or placed on a table.
- Don’t place APs near or inside any metal boxes. Signal degradation will vary depending on the type of metal and box it is, so it’s best to just stay away from them. There is also refraction, reflection, diffraction…T.M.I. It’s really best to stay away from all boxes, but metal is usually the worst.
- Some access points come with antennas. These are typically what we call a rubber duck antenna. The signal propagates from the sides of this antenna like a donut. Therefore, if your coverage area is around the AP, the antenna should be straight up and down. All antennas should be in the same orientation.
If you have to put the AP in an area away from the where people are working, you’ll have to be sure that you are getting a signal close to -67dBm from the devices that are being used. Most standard phones, computers, and tablets are capable of telling you this information. Also, any of the discovery tools mentioned above will tell you this info as well.
That’s actually pretty much it. When you set your access point up, you’ll probably need to go into the advanced settings to access most of these features. Again, around 99.999% of all APs and routers come with unrecommended settings enabled by default. Google can be your friend. Use the wireless network discovery tool to see which channels are “audible” to your device at the location. Pick the channels with the lowest signal to put your AP on. If you see 2 channels next to each other that a clear, you could probably enable 40Mhz bonding. If you are in a downtown environment, you may just have to do some trial and error. Regardless, people still have wireless in the middle of the city. It’s not that it won’t work, it’s just that you may get some slower speeds and the occasional disconnect.
As always, comments and questions are always welcome! I’d love to hear your opinion on 80Mhz channels. I’ve heard quite a few engineers say NEVER use them no matter what, others say “it depends”! What do you say?
…till next time!