WRT54G2//ddwrt - 80% transmission errors

Posted on 2009-02-12
Last Modified: 2012-06-27
I'm having trouble with some wireless access points. i installed ddwrt on them (mostly for fun, but their are other reasons) and ive noticed that im having quite a bit of wireless transmission errors (under the wireless status page).

when i ping the servers from from laptops in various places, i see roughly 10% packet loss, when i log into the router, im seeing roughly 80% tx errors.

any ideas as to why? i already tried setting the ack timing to 0.
Question by:berserkerror08
    LVL 27

    Expert Comment

    > any ideas as to why?
    I see the most obvious reason - buggy Wi-Fi driver on a client or bad link quality.

    Author Comment

    i have yet to nail down a cause for this but between 3 and 40 people are on one of these access points at any given time and no one has trouble connecting. im just hoping the router isnt sending out duplicate packets to compensate for the "errors"

    Author Comment

    i have yet to nail down a cause for this but between 3 and 40 people are on one of these access points at any given time and no one has trouble connecting. im just hoping the router isnt sending out duplicate packets to compensate for the "errors"
    LVL 44

    Accepted Solution

    Exactly what router do you have, and which build of DD-WRT are you using?

    According to the DD-WRT database it appears v1.0 and 1.3 of the WRT54G2 are broadcom-based, while v1.1 is atheros-based (also possibly 1.2). If you can't find the version on the bottom stickers, check the FCC-ID.
    It looks like there have also been v1.4 and v1.5, but it's not clear if those are (or ever will be) supported.

    And there have been at least 3 newer builds of DD-WRT since the original post in Feb. (SP2 build 12548) is Eko's latest build, patched for the milw0rm exploit.

    The latest from the beta Supported Hardware page for v1.0 (and v1.3), which is currently SP2 build 12533, is at

    v24 SP2 Build 12188 for v1.0 (and v1.3), which fixed an obscure (yet possible) exploit in the web management, is

    I believe those are both from BrainSlayer (DD-WRT's primary developer).
    Currently, the latest 'stable' version listed is SP1 (build 10020), which is likely the version you have... but the only way to make that secure from the web management exploit is to disable web management altogether.

    Did you already do the boardflags tweak as recommended by Eko?

    e.g. on the Administration tab, Commands subtab, paste in

    nvram get boardflags

    and click Run Commands
    What value does it return? (the whiteboard will get larger and the returned value will be on the left side.)

    If it's 0x750 you should just get Eko's latest build and flash it on the Administration->Firmware Upgrade tab.

    ALWAYS do a 30-30-30 reset prior to upgrading firmware. Yes, that means having to re-enter all your settings afterwards, but often the settings can change offset locations in (or disappear completely from) the NVRAM...  so do not save the configuration then reload it after flashing, either.
    After you're sure the new firmware has loaded, do another 30-30-30 reset.
    30-30-30 reset -
    LVL 23

    Assisted Solution

    Transmission error or discard suggests a lost packet  that the sender will need to transmit  (if it's a TCP request), or the requestor may need to re-request, if .. e.g. the lost packet was DNS/UDP.

    The Linksys 54G  hardware  is a device designed for  home/consumer use;  3 wireless clients should be fine.  But the hardware is definitely not designed for 40 simultaneous users,  especially if encryption is being utilized, you may be impacting the processing capabilities of your AP.

    Transmission errors normally suggest RF interference by outside sources (e.g. Microwave oven, portable cell phone,  other wireless devices that utilize the unlicensed spectrum) or ineffeciency of the radio.

    You also indicate you are operating multiple APs; well,  different APs may be competing with each other, and causing errors on other APs.

    You might want to try boosting transmitter power as high as 60 or 70, and trying different channels such as channel 1 or 6,  instead of whichever channel you are using.

    Transmit errors may also be caused by network congestion.
    For example, if the total data rate being transmitted exceeds the effective bandwidth of the channel,  the amount of traffic beyond the network capacity will get discarded   (increasing discard/error counts).

    Finally,  transmit errors and effective throughput reductions can result from a misbehaving wireless client;   for example, a client a longer distance from the AP.

    A client with a configuration, wireless card/antenna hardware issue, or a client operating in 802.11b  or reduced throughput mode.


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