Windows Randomly Disconnects from Wireless Network Solution

Broadcasts and Wireless Networks

For all of the juicy details on how I got here, read Part 1 – Troubleshooting Wireless Home Network Random Disconnect.

The answer finally came in, of all places, a Facebook forum.  Turns out the real administrators from Facebook actually help out their users by really trying to understand their problems.  After all, people might just decide to stop using Facebook before they decide to buy a new router.

I don’t remember the question or the exact answer, and I can’t seem to find it anymore, but it came down to this.  If you are running Windows (any kind of Windows) in a small home wireless network, you might have this connection dropping issue.  Why?

Every so often, your Windows computer will for whatever reason want a browse list.  The browse list is nothing more than a way to find computers on a network by name.  It is woefully outdated and nobody with a serious network uses it (quite frankly, they probably block it at every router).  But it works great for the small home network because it takes no setup.

The way it works is that whenever you turn on a computer, once it gets on the network it sends a broadcast out onto the network asking for the browse list.  Normal network traffic has a destination.  But in order to have a destination, you need to know where the other computers are.  A broadcast solves this Catch-22 by being sent to everybody.  Think of a five-year old in a crowded room looking for their mother, “Mom?  Mom?  Mom?”  Everyone in the room can hear him calling out for his mother even though the message is not meant for them.  A broadcast works the same way.

Now, in order for this to work, there has to be just one list that gets updated, otherwise there might be discrepancies between the lists.  To achieve this goal, the computers hold a Browser Election.  Basically, if a computer wants to have the master list, it has to be the master browser.  There is an algorithm on how this election gets one, but the important thing is that it all happens by broadcasts.

Ok, here comes the glitch.  If you have a small area wireless network, then it is possible that all of the computers will receive the broadcast at the same time, and they will all respond at the same time.  This has a technical term; I don’t know it.  When this happens, the wireless router won’t hear everyone properly.  (Think about five kids shouting for mom).  The router will either respond incorrectly, or not at all to one or more of the computers.  This computer will wait for the proper response before it sends any more network traffic.  This is why the connection does not show up in the icon as disconnected.  It isn’t really.  It is just that it will wait literally forever before it sends any other traffic for that proper response.  Since the router thinks it already responded (or didn’t know it needed to respond), no signal will ever be sent, and BOOM, your connection is dropped.

If you have a big house, the difference in signal between your master bedroom and the kitchen is probably enough to keep this from happening.  But I live in a bungalow style house and my wife, and I often share the same room, so the distance from router to computer isn’t far and the computers are even closer together than that.  I’m sure there is a ratio of some sort here where if you are too close or too far, you’ll never have a problem, which is why no one ever believes the people who do have the issue.

Advanced Router Settings

There is a fix!  First off, if you do have Intel 2200BG wireless adapters you do need to get new drivers if you still have the original ones.  The way you can tell if you need new drivers is if they allow you to choose WPA-2 with AES or not.  If they only allow you to choose WEP or WPA with TKIP, they are too old.  Otherwise, if all your equipment allows for WPA-2 with AES, then you should be ready.

Log into your wireless router and look for the advanced settings.  It might be called something different, but basically you are looking for where you get to put numbers into certain parameters, not where you get to put your password or SSID or anything like that.

You may not have all these settings.  That might be a problem, and it might not.  Change what you can and see if it helps.

Most wireless routers come pre-configured by default with their ideal settings for a perfect environment.  And why not?  Always hope for the best.  If your wireless network keeps dropping, then you are looking to tweak some of these settings.  Yes, they will technically slow down your wireless network, but I will bet you that you only rarely consume your full bandwidth anyway, especially if you mainly use your wireless to share an Internet connection and a printer or two.  (Your Internet connection is way slower than your wireless.  My Comcast Internet with one step upgrade is something like 7 Mb/sec.  The wireless goes at 54 Mb/sec so even if I lost 3 Mb/sec off the wireless I’d still be fine.)  Besides, what is worse, a connection that keeps dropping or one that is a teeny tiny bit slower?

The settings you want to tweak are the fragmentation threshold and the RTS number (they might be called something slightly different, but you should be able to tell them.)  The fragmentation usually comes set at 2346.  Drop it to 2306.  The RTS usually comes at 2347.  Drop it to 2304.  If it works, then here is your virtual high-five.

If not, then lower the Beacon (usually set at 100) to 50.

Still doesn’t work.   Go to your computers and look at the card’s configuration.  If it lets you choose between RTS and CTS, choose RTS.  Otherwise, the RTS changes at the router will just be ignored.

If you still don’t have it, make sure that you actually have the same issue.  Here is a summary of the symptoms:

• All computers can and do connect to the wireless when first started.
• When the connection drops it is seemingly random, that is it doesn’t always drop when you do a specific thing.
• It isn’t just the one computer that drops.  If you have this problem, then all of your computers should be just as likely to drop as another one.
• You don’t have other errors in Event Viewer (except for browser, live update, automatic update, etc…)

If so, then try adjusting the settings down a little bit at a time.  These numbers make big changes for small values, so start with something like 10 less for the fragmentation and the RTS and something like 2 or 3 less for the beacon.  Also, always keep the RTS exactly two lower than the fragmentation.  If you get down to 1800 or something, you are barking up the wrong tree.  Sorry.

Good luck.  I hope this helps.

UPDATE 02/2009: It appears that our friends at Linksys are better at wireless networking than our no longer friends at Trendnet.  After installing a new Linksys wireless router with a feature we needed, this problem disappeared despite not reconfiguring the router to behave as above.  Your mileage may vary, but based on this experience, if you don’t want to mess with the configurations detailed here, you might just want to watch for a good deal on a Linksys Wireless router instead.