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Is Your Wireless Router Stealing Your Bandwidth?

December 14th, 2009

keep the antenna highI thought I’d write a post explaining some of the oddities of WiFi, why your wireless Internet performance can go from great to miserable in a matter of moments, and what you can do to improve the situation when your router decides to be “decidedly unhelpful.” Wireless connections can be an invisible and frustrating part of Internet connectivity, especially when you are running online voice, video and high bandwidth video games. This post explains some of the reasons for wireless system behavior, and how to improve the behavior and reliability of your wireless system.

Could Your Router Be Working Against You, Without You Noticing?

Most applications that you run on a personal computer (Mac OS X or Windows) do not require much performance from an Internet connection. “Email works” doesn’t really tell you that your wireless system and router are behaving properly. Sending and retrieving email happens in the background, usually does not involve a lot of network traffic and is not very time sensitive. If your emails took twice as long to send and retrieve, would you notice it as a huge problem? Probably not, although you might think “that was a bit slow.” Loading most well designed web pages also requires very little bandwidth, even with some of the new snazzy interactive features. It turns out that the speed of your connection can vary a pretty large amount over time with these uses before you would notice the issues.

You might have a very different reaction with this “seems to be ok” connection if you try to hold a long Skype video call without dropouts and frame freezes, download a movie from iTunes, run HD video from a web site, run a 3D interactive game that either requires fast response (a shooter game such as Halo or even old-school games such as BZFlag), or use a virtual world such as Second Life. These realtime-focused applications often point out network problems that stay masked during normal business and surfing uses of the Internet.

Is There A Fast Way To Check My Internet Performance?

SpeedTest.net demoI usually use http://www.speedtest.net/ for quick performance testing. The system has many access points, so you’re likely to get a good reading from a connection point near you, and the results seem to be pretty consistent. (This is just a general tidbit from my experience – I have no affiliation with the site, and your mileage may vary!)

Click the thumbnail at the right to see “How to use SpeedTest.net in 48 seconds!” (mp4 video). This video demo has voice narration, so please have your sound on before playing it.

What Numbers are Good?

“Good” performance depends on the type of Internet service you have chosen. If you have some paperwork or know the URL of your provider’s web site, check there for the speed of your service. If you’re not sure, here are some common offerings:

Home DSL:  about 768 kbps download

Cable Internet: about 6 Mbps download (sometimes faster)

Fiber-optic: well over 10 Mbps and often much higher (the demo was run on a 20 Mbps service)

These are typical numbers. You should check your paperwork or the vendor’s web site to be sure of the target numbers for your specific service. If you see numbers at about 75% or more of the theoretical performance for your service, all is probably good. If you see numbers notably lower and there is no one else doing something on your network that uses a lot of bandwidth “something may be afoot!”

But Wireless Internet Was Just Working. What Could Be Wrong?

There is a dark little secret of wireless standards, including WiFi (the wireless Internet standard used by most wireless Internet routers). Ready? This is going to seem unbelievable.

WiFi wireless routers and many household wireless phones use the same frequency ranges (channels, like a radio station). The manufacturers of these devices made them pretty smart over time, so that they would check at startup to see if a channel is busy, and hop to a free channel if there was interference. This frequency-hopping behavior is common on both routers and home wireless phones. That sounds great, right? Everything checks to be sure it won’t interfere, and it all just works, right?

Unfortunately… it isn’t quite so. The WiFi and phone systems have different standards, and they don’t do so well at recognizing interference from each other. In addition, wireless phones can frequency hop between calls. They may start the day on a channel that does not affect your wireless Internet, and at some point later on, decide to hop to a channel that makes big problems.

Did I remember to mention that these days wireless house phones have a pretty long range, and that a neighbor’s phone might interfere with your router in seemingly random ways depending on where they are in their house, and where your router is in your house?

This is fun.  Maybe not!

In addition, if you put your cell phone down near the antenna of your computer or router, it can cause various types of interference symptoms, from distorted voice on computer voice calls to performance problems.

The Quick Fix That Usually Works

The quickest fix, and the one that most often works, is to reboot your router. I am not talking about your Cable modem or DSL modem or Fiber junction point — this is the box that provides wireless access. It often has one or two antennas sticking up. You’ll want to either turn its switch off, or unplug the power supply that connects to it, let it sit for about 10 seconds, and then turn on the power again. It may take up to a few minutes before all the lights look normal and it’s really connected.

Why does this work? If there is a frequency conflict with some other interference source, the router will notice that interference at startup, and hop to a channel that is clear. As you can tell from the description above this is not always a long term solution, but will often work for some time.  In addition, I’ve noticed that a wide variety of routers “just need to be restarted once in a while” and often show low wireless or local performance as a symptom. This could be due to some issue with the connection to the ISP, and I haven’t really spent enough time to get answers that line up from the router vendors and ISP’s. (Quick aside, if you’re at a public WiFi spot and the performance is awful, you’ll sometimes be able to get back to good performance just by asking someone there to reset their router too!)

If you know what you’re doing and want to tinker around, the administrative controls for most routers will let you choose a specific channel, rather than having the router automatically choose a channel. If you know or can figure out which channel commonly causes conflicts, you can set your router to use a known free channel. This takes a good amount of time, and all it takes for the answer to be wrong is for a neighbor to buy a new wireless device, so I usually do not bother with this strategy.

Depending on your computer(s), your router and how your Internet Service Provider’s systems work, you may have to reboot your computer(s) after rebooting your router.

Geek tip: If you know how to get your machine to request a new DHCP address, do that – the computer reboot forces a new DHCP address to be acquired, but this process is more involved than many users want to deal with.

What If The Quick Fix Doesn’t Work?

If a router reboot doesn’t fix your connection performance problems, you should first check the performance from a machine that is hardwired to the router, with a cable that directly connects from the computer to the router (no wireless). If that connection is also really poor in performance, the likelihood is that your Internet Service Provider has a problem somewhere in the chain. I have no magic for that one… you may be on hold with their support telephone folks for a while to get it sorted out. As a quick aside, I’ve learned that if you call an ISP and you hear “high call volume” on their answering system, the likelihood is that you’re not the only one having problems!

A Note About Antennas And Signal Strength

This is another maybe surprising technical tip. When you see a straight antenna sticking out of either a computer or a wireless router (or any other straight antenna for that matter), in which direction would you expect it’s strongest signal? Many people would say “the directly that the antenna points.”

Unfortunately that makes some gut sense but is completely wrong. If you draw a line out the tip of a straight antenna, that line is the absolute weakest signal from the antenna (if it is sending out a signal) and the absolute weakest direction for it to receive a signal!

To set up your system for strongest connections, make sure that the antennas on your router are at right angles (90 degrees) to the most common places you will use a wireless computer in your house (or office), and make sure to position the antenna on your computer at right angles (90 degrees) to the path from your computer to the router.

In addition… metal blocks wireless Internet signals, so… it’s probably best not to have a big metallic thing, like a refrigerator, a metal file cabinet, a big laser printer, an entertainment center, a screen door or other metalwork in the path from the router to wireless devices. You might get away with it, and it could work, but you will probably get higher signal strength, less interference, and faster performance if you place your router with these issues in mind.

Hopefully this post will help both with understanding why wireless connections are less predictable than hardwired connections, and in helping you to know how to take care of the issues when they occur.

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  1. Dave Lustig
    December 14th, 2009 at 20:39 | #1

    Joel – a reminder: Wireless Routers’ signals use the 2.5GHz frequency band. If your other wireless devices at home run at 5.6GHz, your source of interference is probably something else, like a neighbor’s wireless router.

  2. December 14th, 2009 at 20:56 | #2

    Thanks – that’s true. There are newer phones that do not interfere. I keep being surprised at how many old ones are in use, and the problem of new access points showing up in the neighborhood is an on-going issue. I’ve noticed that independent of which router I’m using, they do seem to need to be reset once in a while to restore good signal level and throughput, and have often wondered if that is a symptom of the ISP’s equipment being reset or reconfigured.

    This article http://en.wikipedia.org/wiki/Electromagnetic_interference_at_2.4_GHz points at some other interesting interference sources, including microwave ovens!

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