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Large wifi file transfer= :(

Discussion in 'Tomato Firmware' started by half, Jun 14, 2007.

  1. half

    half LI Guru Member

    I'm running a freshly NVRAM resetted 1.07 tomato on a WHR-HP-G54 that shows 54Mbps and 5 bars of signal strength on a 3945ABG client running the latest driver from intel when doing nothing or browsing the web, but as soon as I perform a file transfer with a "large file" (anything that takes more than 10 seconds so I can watch the connection) or run a speed test that saturates the UL or DL I get some funny business:

    - The 54Mbps drops to 48, then 36, then 12, then 9, then 6, then 5.5, then 1.
    - It floats back up to 24, then hovers around 12 to 5.5.
    - The signal strength never goes below five bars or about 73 on quality.
    - If I use channel 1 I can't get more than 3Mbps down and 0.3Mbps up. Keep in mind tomato says nobody is even within range on that channel to be detected at the weakest signal strength, and my laptop is 10 feet away from my router in the same room (not going through any walls).
    - If I use channel 6 or 11 (which do have other routers on them within range) I get 7-11Mbps down and 1.9Mbps up. I should be getting 15.6 down and 1.9 up.

    What have I tried? I've tried using the last 6 drivers from Intel for the 3945abg, I've tried the disable power saving trick on the adapter in the driver, I've tried Factory/NVRAM hard resetting my router, re-upgrading fresh to 1.07 from 1.06, using the windows wifi client instead of the intel wifi client (save exact behavior either way), changing to G-only mode (no diff)...

    What's my question? Has anybody here ever seen this kind of behavior before and if so what causes it? Is it tomato or the router hardware or the laptop wifi driver or what? How in the world can the signal strength stay at extremely good quality with a 3-10 foot distance yet drop the speed to 1Mbps under full bandwidth utilization? Why does channel 1 do worse than 6 and 11 when it's empty and 6 and 11 have multiple routers on them?

    I've never had this happen before that I know of, but I've never looked for this before. I realized this was happening yesterday when I tried to do a file transfer from my desktop to this laptop on a 1.5GB file and it said 200 something minutes and I went wow, that's waaaay too long for a sustained 20Mbps at least and then I checked the speed and it said 1, then 5, then 6, then 9, then 5, then 1, and so on, but the bars were all green and I went WTF???

    If you need more info tell me.
     
  2. GeeTek

    GeeTek Guest

    I've had a total of 4 buffaloes fail. 3 of them were a gradual decline and had similar type symptoms as you describe. I would pretty strongly lean in the direction of router hardware fault. The HP has a pre-amp that can sometimes cause funny things like this to happen in certain environments. Try turning off the pre-amp, and also be sure to use 10 mW output, no more. If you have run the unit at higher than 35 mW, there is a good likelihood that this damaged it.
     
  3. half

    half LI Guru Member

    I've never raised or lowered the default 10mW power cause I read it was supposed to be that low because of the amp. Where do you go in tomato to disable the amp?

    It would suck if this was a hardware failure because this thing is flawless with anything physically plugged in. My desktop gets perfection 100% of the time from this unit and has since day 1.
     
  4. frenchy2k1

    frenchy2k1 LI Guru Member

    the 2.4GHz band (where 802.11b and g networks operate) is unregulated. This means that it is quite crowded. Some of the devices that have emissions in that range are:
    - wireless networks (duh...)
    - wireless phones (not cell. Just woreless. they use 900Mhz, 2.4GHz or 5.8GHz)
    - microwave ovens
    So, the fact you do not catch any other networks on your adapter does not mean you do not have pollution on that frequency.
    I've had a similar experience: I live in a crowded appartment complex. Got a wireless router, do a site survey and finds people on channels 6 and 11. So I think "nice!" and go to use channel 1 all by myself. I experienced lag and packet drops. Since, I've switched to 11 and my network work much better.
    To overcome the noise of my neighbours, I pushed the power of my signal (linksys SL54G). It worked, but I got MUCH better results once I just added a reflector to my router's antenna.

    So, my advice is to try all the non-overlapping frequencies (1,6 and 11) and if you cannot touch the power, try to add a reflector to your router:
    http://www.freeantennas.com/projects/template2/index.html
     
  5. half

    half LI Guru Member

    Wouldn't the signal strength reflect any interference or noise? That's the whole mystery of this thing...you shouldn't get 53Mbit fluctuations in negotiated speed with 70-85 quality signal strength as shown in tomato and on the wireless adapter. Noise and interference make the signal go down or at least vary, and it never does, either at idle or under "load." I've been places where it's clear that interference is affecting the quality of the connection because both the signal quality and the speed fly all over the place, like if you set up your gear next to a 2.4GHz wireless phone and make a call. This is not that kind of situation.
     
  6. GeeTek

    GeeTek Guest

    Telnet into the radio.

    > nvram set boardflags=0x1758

    to turn back on;

    > nvram set boardflags=0x2758

    After entering either command string, continue with;

    > nvram commit
    > reboot

    I need to test some more, but I think that Ver. 7 may be rigged so that this is no longer effective. If it still is, you will see a drop of about 12 or 15 dB for any given received signal. I have noticed that in close environments lowering the xmit power to just what you need helps stability by reducing the strength of reflections that will interfere with the primary signal.
     
  7. digitalgeek

    digitalgeek Network Guru Member

    Can you post a pick of your router, I would like to see an actual router with the reflector on an antenna... I have also noticed that this is based on a single antenna router...
     
  8. half

    half LI Guru Member

    I just tried restoring the Buffalo 1.4 firmware and it didn't make any difference whatsoever. Guess I really do have a bad router... :(
     
  9. paped

    paped LI Guru Member

    Must admit I am not an expert on wireless so I will stand corrected here but with my understanding this may not actually be a problem as such, just how the router works. My understanding is that when you have low traffic levels and a good signal it (any router) will give 54Mbps but as you add traffic the noise will build on the link so the router will step down to effectively the lowest working config then try to add to the speed in steps until it gets the best possible signal/traffic/noise ratio....
    I know that my WRT does similar thing and often goes down to 11Mbps then builds the speed back up near the start of a large transfer and often never returns to the full 54mbps until the transfer is completed even with a good signal. I have also seen other routers Netgear etc do a similar thing.

    Hope this helps...
     
  10. azeari

    azeari LI Guru Member

    well tts true to some extent, however my wrt never drops that low.. in fact, i get sustained(not just e link) speeds of at lest 24mbps when transferring stuff between my backup serv and laptop(wirelessly). I do notice that the cpu usage on the box adds up quite abit when doing wireless transfers though, guess this could affect it quite a lil. Of cause it depends on the encryption scheme you're using
     
  11. half

    half LI Guru Member

    I'm using 128-bit WEP and I've tried with it off but it didn't make any difference. I'm not a wireless expert either but I can't see any reason for it to re-negotiate the link speed lower when the signal has such a high quality (70-80%). If it's noise that's dropping the speed it should reflect that interference in the signal strength or signal to noise ratio or RSSI or whatever but it never fluctuates...at least that's how I understood it.

    Anyway I'm just gonna buy another router and if it's a hardware problem this will prove it. Anybody know if 1.07 supports the new Buffalo WHR-G125? The DD-WRT camp has a beta firmware out that works with it and Brainslayer says it has a 40MHz faster CPU and the wireless side is integrated directly into the System-on-a-Chip (it's a new broadcom version number and everything). Supposedly it's even better than the WHR-HP-G54, although they're supposed to be releasing an amp'd G125 in the next few months.
     

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