Wireless dropping frequently for brief period WRT54G

Discussion in 'Networking Issues' started by outie, Nov 30, 2006.

  1. outie

    outie Network Guru Member

    Hi, I wonder if anyone else has this weird issue with their Linksys WRT54g/s and how you manage to solve it. My friend has the same problem too.

    First of all, I have already tried different firmwares, including stock, thibor, dd-wrt, and tomato, but they all have this issue. Secondly, I have 2 routers, 1 G and 1 GS. Both have the following problem:

    My routers (G/GS) would drop ALL wireless clients periodically (5 clients, all at the same time), few times a day. XP would show a message about "Unable to connect to preferred network". During this period, the wired side is working fine. All the clients are also able to see the AP/router in "view available wireless network", but cannot be connected to. In a period of about 1-2 minute, the clients sometimes can connect back but then get dropped immediately. After about 2min, the clients connect again so everything is back to normal. No microwave running, no 2.4GHZ phone.

    I originally thought it was WDS problem, so I only used 1 router. It still happened. I then thought it's WPA problem, so I switched back to WEP. Needless to say it is still happening. I swapped both G/GS routers. I have also tried ALL wireless channels. Same problem!

    The log does not mention anything about these events.

    Does anyone know what the problem is? And how do you manage to solve it? Thanks in advance.
  2. jgutz20

    jgutz20 Network Guru Member

    when it drops the clients... is it all at once? or all 5 clients get disconnected at random and different times. im assuming the signal strength is decent on these mobile devices
  3. outie

    outie Network Guru Member

    Hello jgutz20, yes it's all at once. All clients experience the same issues at the same time (can't connect back for a brief period, or connected and get disconnected in 5 seconds, then after about 1-2 min all clients reconnect automatically and everything is normal).

    The frequency of when the router does this is totally random.

    I have tried g only and mixed mode, no help.

  4. SuzField

    SuzField Guest

    I have the same problem. I have updated the firmware, updated the driver on my wireless antenna on my laptop (which I knew wouldn't help, but what the heck) With mine, it happens most commonly in 10 to 15 minute increments.
  5. HennieM

    HennieM Network Guru Member

    Do the 2 WRTs, and your friend's, drop at the same time?

    If the 2 WRTs are linked by WDS, I suggest, as a test, you connect them by wire, give them different channels and different SSIDs, get at leat 1 wireless client on each WRT, and see if they drop together. Also, to eliminate a timing issue, start the WRTs up a few minutes apart.

    If they all drop at the same time, you are most likely seeing external RF influence. Could be a HAM radio operator a couple of 100 yds (or even miles) from you, a heavy transformer or other machine, or something like that. I have major "kill network" from a HAM located about 400 yds from me, especially on channel 1 thru 4.

    Also perhaps turn off UPnP in the WRTs - dunno if this is possible, but maybe some clever client is sending funny messages via UPnP.
  6. myersw

    myersw Network Guru Member

    Have you tried different channels? Sometimes things like microwave ovens, cordless phones and other devices operate on the same frequency and cause this kind of problem.
  7. jgutz20

    jgutz20 Network Guru Member

    yes he tried channels but the SSID would be another thing to try..
  8. outie

    outie Network Guru Member

    @HennieM: I am now only using 1 router, but it is still happening. Therefore I suppose WDS is not the issue here. I haven't tried turning off UPnP, but I should also try that.

    @myersw: I have tried all channels from 1-11, same problem. Again, no microwave running when all the wireless clients drop. I don't have 2.4ghz wireless phones either.

    @jgutz20: I have also tried different ssd, totally unique than my neighbor's, and of course that didn't help either.

    Any other suggestions are welcomed.
  9. jgutz20

    jgutz20 Network Guru Member

    have u tried a program like net stumbler just to see what channels were being used by neighbors? which firmware are you currently running.. you just told us that you tried a number of them
  10. outie

    outie Network Guru Member

    I haven't tried net stumbler, but I used the built in survey tool in tomato firmware. I am currently using channel 1. Thanks.
  11. nixus

    nixus Guest

    Can only confirm that same problem exists here too. The only difference is that the lost of wireless part takes place once in 3-5 days. After reset and recongiguring everything runs smoothly again for some days. As it was told only wireless part is affected. Have 2 routers as well WRT54GS v1.1 and WRT54GL v1.1. both running latest Linksys firmware. Was going to try DD-WRT but now start to doubt now whether it will help.
    Really weird things
  12. imdickie

    imdickie Guest

    I have a similar problem. Randomly my wireless would disconnect and reconnect. I thought it might be a heat problem as I have my power cranked up pretty high and am running FIOS 15/3 broadband.

    I made a discovery yesterda that you might want to try. I messed with every single one of my settings to see if I could get a stable signal. I tried everything that was listed in previous posts and then I tried running in "G" only mode not mixed mode. I don't have any legacy devices so it was fine. So far so good. I have been running since yesterday and not had a single drop.

    One more thing of note, I noticed as drivers became stale (Loaded some time ago) for the client adapter the ability to connect and the frequency of drops was higher. Right now I have all fresh installs of client software and am running in G only mode. Something you might want to try.

    Hope that helps.
  13. ArgoNavis

    ArgoNavis LI Guru Member


    I recently had exactly the same symptoms you describe, albeit with a different non-Linksys AP. In my case, it turned out that one of my wired devices was in a DHCP-request loop with the AP's DHCP server. Evidently the AP was providing a somewhat damaged response to the client's DHCP request, causing the client to reject the response and issue another request.

    The upshot was that the client was issuing non-stop broadcast DHCP requests which were going out over the wireless transmitter. IIRC, high-volume traffic will cause the AP to effectively lower transmit power. I'm guessing that since my usual wireless client is toward the outer edge of the normal coverage area, this situation caused it to drop its connection even while still detecting the network.

    I should note that I'm guessing that the issue was an attenuation of transmit power. It may also have been that the AP's processor was overloaded with the WPA encryption on the additional traffic.

    Once I resolved the DHCP snafu, and the AP resumed its usual low-traffic profile, life has been good again.

    Just a thought.

  14. Gikey

    Gikey Guest

    Same problem here but I think know what causing this problem.
    First of all, my conf:
    WRT54GL v1.1 with Thibor15c, three computers 1LAN and 2WiFi.
    I have ASUS notebook with Atheros WiFi card and my wife has HP nx6110 with Intel 2200BG. Computer which always is disconnected first is HP, of course it is a matter of seconds (2-3 sec.). So I have tested HP with PCMCIA wireless card (Edimax - the only I had) and no problems at all. Used again HP with internal 2200BG, problems back. For sure I have replaced my Intel card with a brand new one and got the same results.
    So in my case disconnections were (still are) caused by Intel 2200BG wireless card and I am still looking for solution.
    I suggest you to check if any of your network's computer uses Intel 2200BG, try to eliminate it for a while (day or two days) or replace with another non-Intel card and see what happen.

  15. myersw

    myersw Network Guru Member

    In my experience the Intel drivers are not reliable. At work we see HP laptops with Intel wireless chips giving problem all the time. If you check Intel's web site it is like driver of the day. In the very least make sure you have the latest Intel drivers in any of your systems have the Intel chip set for wirless.
  16. outie

    outie Network Guru Member

    I should mention that a router reset *does not* solve the problem, how weird! I can power cycle it few times and the clients just refuse to connect to it (can't connect or can't obtain IP)

    @imdickie: I tried setting to G-only, but that did not help.

    @ArgoNavis: I only have 1 wired DHCP client, a vonage voip PAP2. I have disabled dhcp for this PAP2, and using manually assigned IP. We'll see how it goes.

    @Gikey: In fact I do have 2 2200BG clients on the network. If this problem persists after trying ArgoNavis's suggestion, I will isolate those 2 laptops.

    I also have 1 3945ABG, 1 Linksys, and 1 Encore clients left. I just loaded the newest tomato that was released today too. Thanks everyone for your help. I will report back if any of the above solves the problem.
  17. outie

    outie Network Guru Member

    I should update my progress so far:

    I have assigned static IP to most of the clients including the wired device per ArgoNavis's suggestion, but the problem is still showing up throughout the day.

    I turned off my 2 2200GB clients, again the problem still persists for my 3 other wireless clients. I am really running out of ideas!

    Is UPnP the problem??
  18. HennieM

    HennieM Network Guru Member

    Don't know how UPnP works, but I tend to turn off anything I do not or cannot configure myself to do just what I say. (Hate software that thinks it KNOWS what I want...)

    Something to try maybe: Run Netstumbler (or Kismet if you can do Linux) on one of your wireless clients, and see what happens to the signal strength and/or noise of your AP's signal when the other clients loose connection. Bear in mind that not all wireless adapters work with all wireless sniffers, and some that work may not show noise.

    If you see nothing there, or even at the same time, run a sniffer such as tcpdump or Ethereal from a wired client, and see if you can detect any funny net traffic just prior to the connection drops. A sniffer may not pick up all the traffic on your net, especially the wireless connections, but I reckon it's worth a try.
  19. ArgoNavis

    ArgoNavis LI Guru Member


    You've really been through the wringer with this issue.

    First, let me say that I doubt that UPnP is likely to cause your wireless connection problems. I do think that UPnP is not a good idea from a security perspective, especially since the web interface on many routers doesn't reveal the ports which have been opened by UPnP. Personally, I'd turn it off, reboot the router, and use other means to open your ports. Regardless of how you want to operate your router in general, disabling UPnP might be a good idea for now, until things are sorted out.

    As I see it, there could be a number of things going on:
    1. Some of your hardware, software or firmware is faulty
    2. Some of your devices are misconfigured
    3. There is an incompatibility between some of your devices
    4. There is a higher-level network problem
    5. The RF strength between wireless devices is poor
    6. You are experiencing external interference (power or RF)
    If I were faced with this problem, I think I would probably set about trying to isolate a method for eliminating each one of these possibilities. You've already tried so many different things that probably should've worked, however, that I personally would suggest you consider starting from a very basic configuration. This might be a royal pain, but then, so is living with the situation you currently have.

    Specifically, I think I would take one of your routers -- perhaps the WRT54G -- and reload the factory default firmware, set to factory defaults. Make the minimum number of changes to allow it to connect to the WAN. Disable UPnP, DHCP, and wireless security. Don't plug any other device into the router. Also, I would plug the router into a UPS, or at minimum into an AC circuit with no other motors, or devices which might create power irregularities -- and I would use a surge suppressor in this case. Then I would select two of your laptops with different brand NICs, and configure them with a static IP, and a minimum of other network-chattering applications. On Windows, perhaps "safe mode" with network support could help. At this point, using only one laptop, I would try to achieve a stable connection. You could set the laptop to do a ping at intervals -- try both short intervals (eg, 1 sec), and long intervals (5-10 minutes), just in case the amount of network traffic has a bearing on connection stability. Then, just let it simmer for awhile. If the first laptop doesn't generate a stable connection, turn it off, and try the second.

    If neither of these two laptops can achieve a stable one-device wireless connection, then I would consider trying this whole configuration at someone else's house (in a different geographical area). This might help eliminate the possibility of local power glitches or RF interference.

    Once you've achieved a stable connection, I would gradually add additional variables to the mix again, one at a time -- with intervals for testing -- until you have achieved your desired network configuration. If, after making some change, you find that the wireless network has become unstable again, then you might have isolated the culprit.

    From my perspective, however, just getting to a point where you have a single stable wireless connection might be a real step forward.

  20. outie

    outie Network Guru Member

    Thanks ArgoNavis for the advice. I should try that approach sometimes.

    @HennieM: I actually tried netstumbler. I ran it when the router disconnected all the clients. What's strange is that, the graph shows the signal/noise perfectly fine as if the client is connected to the router! It just won't let me connect to it.
  21. relorium

    relorium Guest

    uhm i have the same problem at first but it got worse...

    i had some problem with my internet connection before and i asked some techsupport fromthe IP company (it was found out that my connection problem was not because of technical problems some rodents chewed on cable) but after they changed the modem i couldn't connect to the internet wehn i plug it in the router. but if i directly plug it to the PC i can get inernet acceses. So my problem now is how to make it work again i tried to reset the router and install it again.. but nothing seems to work... need desperate help pls......
    at first icouldn't use the wireless connection.
  22. HennieM

    HennieM Network Guru Member

    When you ran Netstumbler, are you sure that your card reported reliable signal/noise? I ask, because I noticed on my setup, that some cards tend to just report A figure, which stays the same all the time. Both your signal and the noise should be a bit inconsistent if the reading is actual.

    What I do, is to disable the wireless adapter, then run Netstumbler (which disables WZC, or I manually disable whatever utility used for the zero config), then enable the adapter. This way, the adapter does not connect to the AP, and you actually see the signal of the router being broadcast.

    I'm still of the opinion that you have external interference. Can you beg/borrow a spectrum analyzer somewhere to see what happens to your spectrum when the connections drop?
  23. i2cyu

    i2cyu Guest

    I think this will resolve your issue with wireless

    Under Wireless tab, select advanced wireless settings; :thumbup: see settings below

    Basic rates: 1-2 Mbps(Default) or your default
    Control TX Rate: 1-2-5.5-11(Default) or your default
    Preamble Type: Long Preamble(Default) or your default
    Authentication Type: Auto(Default) or your default
    Antenna Selection Diversity(Default) or your default
    ....These changes....
    Beacon change to 50
    DTIM change to 1
    Fragmentation Threshold change to 2304
    RTS Threshold change to 2304

    This has worked for me, I have a B router, it would not normally work for a G router.. A different calculation might work. If you have a G router keep the old settings written down before trying these settings in order to restore the settings if necessary.. Hope this helps!
  24. rcordorica

    rcordorica Network Guru Member

    I used to have that problem with my WRT54GL 1.1 and I believe it was caused by two factors.

    1. I had a stable connection for a long time, and then my roommate got a laptop with a 3945ABG card. His client would have a difficult time getting a dhcp response, and it would also cause the whole network to drop while the dhcp was probably locking up the whole system. I had to change to WPA with TKIP only because any other combination would cause his card to drop randomly or give him a very difficult time trying to connect to the AP. I also had to force G only because otherwise it seems the network would get interference from B devices in the area and cause the whole network to stall like you mentioned.

    AFAIK, intel drivers are buggy at the moment (with mem or handle leaks?), and I am still waiting on intel to fix the issue.

    2. If I set the power higher than 70mW I also get the problem you describe. I think the radio heats up after a while, causing noise and the network to drop. After a few minutes the radio would come back, but the higher I pushed the mW, the more often I had random disconnects.
  25. outie

    outie Network Guru Member

    Just an update since my last post:

    @HennieM: Accurate or not I cannot tell. The graph fluctuates and it just appears to be working fine. I am not sure how I can borrow a spectrum analyzer or how to operate it...

    However, I have since disabled UPnP and apparently the problem hasn't appeared yet.

    I also took rcordorica's advice and changed my router power back to 42mV (which had no effect before).
  26. Toastman

    Toastman Super Moderator Staff Member Member

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