Here's a article about WiFi dropping. Microsoft call this "bahviour by design". If you don't want the drops, make sure you have SSID Broadcast turned on.
http://arstechnica.com/news/posts/1080251780.html
Ask Ars: routinely dropping WiFi connectivity
Posted 03/25/2004 @ 3:56 PM
by Ken "Caesar" Fisher
A reader wrote in with a question to which I, too, sought the answer. The question concerns 802.11 wireless connectivity, and persistent connection drops. It's not big enough for a large article, so I'm writing it up here for the community. Alex reports:
I have a problem I know you gurus can help me with. I have a Linksys WRT54G b/g wireless router, and while it worked perfectly for months, now the connection routinely drops every 10 minutes. When it drops, I have to sometimes wait 3-4 minutes before my connection returns. The confusing part about this is that it only happens on one of my laptops, but not on all of them. I have reinstalled everything, but nothing solves the problem. Please help!
It just so happens that one of the laptops in the Orbiting HQ suffers from this very same problem, so I've been able to duplicate this problem on my Linksys WRT54G router, with a Centrino laptop running Windows XP, standing 5 feet from the router. In the quest to help Alex, I started investigating this matter, and sure enough, I found out that people all over various message boards are discussing the problem.
As it turns out, if you use the Microsoft Windows XP SP 1-based Wireless Zero Configuration service to manage your wireless (aka, the "built-in client"), you're probably running into a horrible bug that Microsoft calls "behavior by design." The gist of this is as follows: if your wireless network is set to not broadcast your SSID, Microsoft's wireless manager will periodically drop your non-broadcasting WiFi connection in response to the presence of a broadcasting SSID-based network. You won't fully associate with that network, but the service will pop-up and tell you that there are multiple wireless networks to join, even if you have removed all other networks from your preferred settings (this contradicts Microsoft's report, which says it only affects preferred networks). The upshot of this is that you, the user who changes his default SSID and then sets it to not broadcast (as most security guides, and most hardware setup guides will tell you to do), now gets dropped off your network when you neighbor shows up with his new D-Link wireless router and not only fails to change the SSID from default to something else, but does not turn off broadcasting, either. While many may debate the security benefits of disabling SSID broadcast, it is a practice that is recommended by most manufacturers of wireless products.
Your options are two (2.5, really): you can set your own router to broadcast your SSID, which Alex did and it resolved the problem. Alternatively, you can stop using the Windows Wireless Zero Configuration service and instead opt for another wireless client, namely that which came with your wireless card. Additional testing revealed that if your wireless settings are already configured and correct, you can actually stop and then disable the Wireless Zero Configuration service. The wireless still works, but your Wireless tab will disappear in Networking properties. This solution is not ideal, but it could be used in a bind.
Which do we recommend? We recommend simply broadcasting your SSID and making sure that other security settings are in place (for example, you should be using encryption in the form of WEP or WPA). WEP is inherently insecure, and many would argue that hiding your SSID is a waste of time. It one of those "if they really want you, they'll get you" kind of scenarios, and 128-bit WEP is the best deterrent unless you have hardware that supports WPA. Failing that, turning off the service when you're having problems can help. You can enter this at the comment prompt, for example: net stop wzcsvc . Replace stop' with start' if you need to start it again. You could make a batch file to make this more convenient.
If your connection is dropping and you're not being asked to connect to another network, make sure that you have not checked the "Enable IEEE 802.1x authentication for this network" checkbox, as this can also cause problems (but was not the root cause of this issue).
http://support.microsoft.com/default.aspx?scid=kb;en-us;811427&Product=winxp
Your Computer Connects to an Access Point That Broadcasts Its SSID Instead of an Access Point That Does Not Broadcast its SSID
View products that this article applies to.
SYMPTOMS
When your Windows XP Service Pack 1 (SP1)-based Wireless Zero Configuration (WZC) client computer is in the proximity of two wireless access points, and one of the access points is broadcasting its Service Set Identifier (SSID) but the other is not, your computer always connects to the access point that is broadcasting its SSID. This occurs regardless of the preference order of the networks that are configured on the Preferred Networks list.
Additionally, when your computer is connected to an access point that is not broadcasting its SSID, and another access point that is broadcasting its SSID is enabled nearby, your computer automatically connects to the access point that is broadcasting its SSID.
CAUSE
All access points must broadcast their SSID to identify themselves to potential clients that are in the area. Disabling SSID broadcasts on an access point is not considered a valid method for securing a wireless network.
STATUS
This behavior is by design.
MORE INFORMATION
The Windows XP WZC service dynamically selects the wireless network to which your computer connects based either on your preferences or on your default settings. This includes automatically selecting and connecting to a more preferred wireless network when it becomes available. If no preferred wireless network is found nearby, the WZC service configures the wireless adapter so that there is no accidental connection until the wireless client is in range of a preferred network. For more information about the WZC service, visit the following Microsoft Web site:
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/columns/cableguy/cg1102.asp
The information in this article applies to:
Microsoft Windows XP Professional SP1
Microsoft Windows XP Home Edition SP1
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