Huge headache: yoyo effect

[thib_gc]

Hi everyone,

For the past 10 days or so my home wireless network has become very unstable and makes it virtually impossible to do anything at all. It's a huge headache.

I've been browsing this forum and many others, digging through hundreds (literally) of queries on Google to try and extract similar problems, and I've found interesting things, but I still can't solve my problem. But I'm sure I'm not alone!

The network consists of a Linksys WAP11 v2.2 access point, that is connected to the DSL modem through a Webramp firewall. There are no wired components apart from that. Up to four machines use the network with various 802.11b cards. The two main machines are desktop computers with Windows XP home, one with a US Robotics USR 2216 and one with a D-Link DWL-520+ (both PCI adapters). There is also another desktop computer running Linux (RH9) using the same USR 2216 as the other and running a crazy-off-the-wall driver (http://acx100.sourceforge.net), and a Windows 98 SE laptop with a PCMCIA adapter by Robanton.

The problem is the following: when two or more machines are on at the same time (and access the network), suddenly the network connections are dropped randomly several times a minute, in a maddening yoyo effect. The disconnection lasts a few seconds and the connection is established again, but not for long. You can see this very well on this screenshot (http://internet.maintenant.free.fr/temp/k2.jpg), where the bar graph shows about one minute's worth of online/offline. It becomes impossible to establish SSH, telnet, FTP, IRC or messaging connections, and browsing the web requires a phenomenal skill at pressing "reload" at some lucky moment.

I have the latest firmware and drivers for each and every piece of hardware, and all Windows systems are up to date. All hardware agrees on channel, RTS threshold (2432), fragmentation threshold (2304), SSID, etc. The MTU on all Windows machines is set to 1420.

It used to be that there were sporadic periods of unreliability and yoyo effect, but since the second main machine (the one with the DWL-520+) was brought in about three weeks ago, things have gone worse and worse and have reached a critical point where it becomes impossible to do anything.

Any ideas? (suggestions like "go wired" or "drop Windows" have already been considered and need not be repeated, thanks)

[Greenstead]

Unusual problem - no obvious answer.

Some thoughts (unlikely causes but worth considering):
- A virus might cause similar to this as it swamps the internet connection with ICMP pings. You should virus check all PCs with up-to-date AV. You might put zonealarm on each PC to trap outgoing connections.
- Another wireless network could cause your PCs to switch connection. There is a bug in XP which allows this even though your settings may inhibit it.
- I guess sporadic interference might also cause your symptom. Change channel in the AP to the other end of the range.

[thib_gc]

Thanks for your message. My machines are virus-free but that indeed could have been the cause. That XP bug sounds like an interesting lead. If it is an intereference, then there is no obvious one I can think of (I checked my phone and microwave early on).

Since it is virutally impossible to do anything with several machines, the past two days or so were spent trying to schedule non-overlapping computer access. More details have come up with a one-machine scheme.

When one machine is online, the connection gets randomly dropped whenever there is any kind of load, even the slightest. Loading a webpage, for example, causes a sudden amount of activity, and so the connection is dropped at least once or twice before the page and its images are loaded. Initiating a connection to something (a machine via SSH, a stream on RealPlayer, etc.) also causes a connection drop.

What's weird is that this has happened only recently. I carefully checked and re-checked and cannot think of any new hardware of software that was set up recently at all -- nothing has changed.

Could it be that the Linksys AP (WAP11 v2.2) has blown up a few components inside, causing to be dysfunctional without it being obviously dead? The reason I'm starting to think it's the AP is because the situation seems to be fairly independent from which machine is being used or which brand of wireless card.

Second reason is, it doesn't seem to come from the firewall or the DSL modem, because the yoyo porblem happens also within the network, without going out to the rest of the world through them.

I'm quite close to throwing out all four wireless cards and the AP, and run buy two wired hubs and 150m of cable (which is what I would need to replace the current set-up) -- yet they cost me a pretty penny. So, any help is appreciated.

Thib ;-)

[Greenstead]

As you say it does sound as if the WAP11 is the problem.

We have seen a few posts about strange connection problems with a WAP11 V2.2

Do you have the latest firmware loaded.

Other suggestions tried have been:
- Enable SSID broadcast in the WAP11.
- Turn off power management in the wireless adapters (in driver configuration).

If you still have problems I would call Linksys with a fault report on the WAP11.

[thib_gc]

I finally managed to get a hold of another AP. A friend lent one to me and I had to drive over and... (sorry that's besides the point). Everything seems to work fine now. I've narrowed it down to the RJ45 jack behind the Linksys AP. It seems that the jack isn't hugging the circuitry behind tightly enough. We figured this out by reading some logs from the firewall, that had an unusually high frequency of ARP timeouts, that we thought were due to the jack coming in and out of limbo (hence the yoy effect, too).

Thanks for your help,

Thib ;-)

[cszeto]

If it's a matter of some poor soldering connections, then it might be a toss up as to sending it back for warranty replacement or just breaking out the soldering iron. It might take a while if you send it back.

I ran into that with two different pieces of Speedstream gear. Poor manufacturing QC on their part. I may have to steer clear of their stuff, considering I only own two pieces of gear by them...