Wifi FTL

October 27, 2007 7:52 AM

WifiQ: Why does my laptop disconnect from my WAP?

I have the following:

Dell Inspiron B130 (xp)
Dell Latitude D620 w/ all wifi power management turned off. (xp) - Intel Pro 3945ABG
Desktop w/ DLink WIFI w/ ubuntu

Linksys Business Wireless AP
Linksys WRT54G (V3?) running DD-WRT, underblocked, underpowered.
Buffalo Something something running DD-WRT Generic

The issue is my laptop will disconnect from the WRT54G randomly. Initially I thought it was a power, channel, or overheating issue, but the desktop *never* loses connection, nor does the B130. It is only my D620. There were some articles related to power management causing the Intel Pro wireless to lsoe signal, but I have disabled that.

The issue only occurs on the WRT54G. My laptop stays connected 24/7 to the junk Linksys business wireless router, and the BUffalo running the same firmware.

The desktop and B130 stay connected to all three, but the Linksys business router seems underpowered, and the desktop will lose signal strength (it averages ~20%, but if the cat lays next to the TV, it drops). I would like to use the WRT54G and not pay $60 for a new Buffalo (this one is stolen from work), but the Buffalo seems to fix the problem.

Why would two waps, same firmware, similar hardware, similar laptops exhibit this problem? I had pings running on all three machines, and the b130/desktop never seem to go above 2ms, while the D620 dropped signal half way through the night. It even occurs while on AC, and I am actively using it. Reconnecting doesnt' fix it, I usually need to disable and reenable the device in Network control panel.

posted by SirStan to computers & internet (7 answers total)

My laptop is the D620 for clarification.
posted by SirStan at 7:53 AM on October 27, 2007

Other pertinent information:

This happened at my old apartment, and I assumed it was due to excessive waps in the area. Now its on its own channel, the only other wap is 10 channels away. The WAP is on a UPS, and connected through a switch to a cable modem to attempt to isolate a cable-modem-caused issue. The WAP has been used with the wrong power cable before, and was locking up due to that. This has been an issue that I have had that arguably started around that time, but I would assume if it was a wap issue, it would happen for all users, not just my laptop. It doesn't lock up. Theres no errors in the messages log (dd-wrt is linux based).
posted by SirStan at 8:08 AM on October 27, 2007

Depending on a possible difference of distance between the desktop, laptop and WAP, I've had both microwave ovens and cordless phones (2.4GHz particularly) cause problems with my wifi.
posted by rhizome at 9:04 AM on October 27, 2007

rhizome: I have had the same problem... but there are no 2.4ghz phones present, and the two other waps don't have the isse.

Also my laptop lives about 6ft line of site from the WAP in my living room. It shouldn't disconnect even with a neighborly 2.4ghz phone or microwave. Even if it did, why wouldn't it automatically reconnect? It seems like I need to disable it and reenable it to make it work. (It will connect to another WAP just fine, but refuses to connect to my wap).
posted by SirStan at 10:19 AM on October 27, 2007

Sorry for a non-answer, but I used to have a very similiar problem before I switched to the tomato firmware (for other reasons).
posted by philomathoholic at 1:27 PM on October 27, 2007

I should note that since my last comment, Windows has twice informed me that there were no preferred networks in range. The first time I reconnected by "Repair this Connection", the second time it happened, it reconnected after a little bit (30 seconds or so).

Back when this was happening more often, for longer, and more persistently I would fire up Netstumbler and checkout my AP. After running it for a second or two, my network would show up, so I wasn't able to gather any real information. The pages I was reading online at the time led me to believe that Windows' Wireless Zero Configuration (WZC) might be to blame. After stopping the service, some people have had less disconnections.
posted by philomathoholic at 12:22 AM on October 29, 2007

I am having similar issues on a Linksys draft-N [150] with the latest dd-wrt V24 release candidate [RC6.2 last I checked], but I was seeing it from V23 too. When any of our wireless devices go to sleep or somesuch, we lose the connection. My wife has the exact same model Latitude as you and can get it going again by using "Repair Wireless Internet Connection" in XP, but my MacBook (Leopard) is epic fail. It says it connects to the network, but self-assigns an IP and never actually gets anywhere. Sometimes manually assigning it an IP on the local LAN fixes it except when it doesn't. Sometimes connecting to the neighbors' wi-fi, then switching, solves it.

Last night I downloaded a new build released by one of the individual developers, Eko. Not the release candidate, but his own build, in a separate directory on the dd-wrt official site. [I used the latest one as of this writing, 8795.]

It's only been eleven hours and I spent about half of them asleep and a couple of them at work, but the connection problems were gone following last night's upgrade, and this morning when I got up.
posted by britain at 7:58 AM on January 30, 2008