Best bandwith with WDS and 4 WRT54GL

Discussion in 'Tomato Firmware' started by Nox997, Jan 3, 2008.

  1. Nox997

    Nox997 LI Guru Member


    As my village is rarely supplied with ADSL-Network, only my neighbour has a 384/64 kbit/s connection. He shares this connection with me.

    For this task, I bought 4 WRT54GL and installed Tomato on them and set up WDS as follows:

    1st WRT54GL: Gateway and Access-Point + WDS (Access-Point for my neighbour).
    2nd WRT54GL: only WDS, linked with 1st and 3rd WRT54GL
    3rd WRT54GL: only WDS, linked with 2nd and 4th WRT54GL
    4th WRT54GL: Access-Point + WDS, linked with 3rd WRT54GL (Access-Point for me)

    Only the 4th WRT54GL has ethernet devices attached to it.

    My question is:

    Would it be better for the bandwith between the 1st and 4th WRT54GL, if I set the 3rd WRT54GL to Access-Point + WDS and the 4th to Client-Mode?

    Or would anything else be even better than my current-config? Less repeater-stations is not possible.

    Thanks in advance for your suggestions!
  2. Toxic

    Toxic Administrator Staff Member

    how far are you transmitting from each WRT? have you tried external directional Antennas/Reflectors?
  3. Garrett804

    Garrett804 Network Guru Member

    I run 3 WRT54G's in AP + WDS mode all WPA w/AES
  4. dirtyclyde

    dirtyclyde Network Guru Member

    [1st] WRTSL54gs ap+wds gateway DSL on WAN (wds > 4 WRT54) linux PC + Vista Media PC
    [2nd] WRT54gs ap+wds router points to [1st] xbox360 + laptop (den)
    [3nd] WRT54gs ap+wds router points to [1st] old xbox + laptop (living room)
    [4nd] WRT54g ap+wds router points to [1st] DirecTV HR20-100 HD-DVR + laptop (bedroom)
    [5nd] WRT54gs ap+wds router points to [1st] linux PC (bedroom)
    all run fine at 1.5 to 3.0 mbit

    All run WPA w/AES same SSID Tomatoe upgrade from 1.13 to 1.14
    WRTSL54gs Thibor17 rc3

    2800sf house
  5. Nox997

    Nox997 LI Guru Member

    ok. thank you!

    which tranfer rate do you reach from 5th to 1st router? And are they connected in line or are all connected to the Gateway directly? ("star"-like)
  6. dirtyclyde

    dirtyclyde Network Guru Member

    I just tested , I have AT&T 6meg service on the first WRTSL54gs ADSL,
    Westell-WAN-WRTSL54gs -->WDS-->WRT54GS (wpa/aes)-->100mbcard-->laptop (Atlanta-->Miami) shows 5494/428 (615miles to test site)

    all WRTs AP+WDS (WPA/AES) I either use 100mb interface or wireless cards, prefer 100/10 interface

    I orig had Thibor on WRTSL54gs and loaded Tomatoe 1.14 on WRTSL54gs
    tomatoe 1.14 on my WRTSL54gs and WRT54gs
    Laptop is a old Toshiba 1805 with 512mb memory a real rag!

    all WDS routers connections are 5494 to the gateway WRTSL54gs no matter were I go in my house, as I move around with my wireless card it remains the same 5494/428.

    Tried all channels, channel 1 was the best for me, I run G-only mode , all defaults but frame burst enable , 100 on xmit, G-only, preamble short, beacon 20.

    people around my house use channel 1 also, channel 6 and channel 11. But have no problems, the farest WRT is about 20 meters.

  7. HennieM

    HennieM Network Guru Member

    To answer your original question

    For you particular setup:

    real speed = 1/(3+1) = 1/4 speed of ~ 22Mbps = ~ 5.5Mbps as you have 3 single radio repeaters (#2, #3, and #4) [assuming you have full speed (54Mbps) connections among all wireless devices]

    real speed = 1/(2+1) = 1/3 speed of ~ 22Mbps = ~ 7.3Mbps as you have 2 single radio repeaters (#2 and #3) [assuming you have full speed (54Mbps) connections among all wireless devices]

    When AP4 is in client mode, you can only have a wired connection to it, so
    real speed = 1/(2+1) = 1/3 speed of ~ 22Mbps = ~ 7.3Mbps as you have 2 single radio repeaters (#2 and #3) [assuming you have full speed (54Mbps) connections among all wireless devices]

    Thus, you should see virtually no difference between AP4 being an AP+WDS or a CLIENT, but if #4 is a client, you cannot have wireless PCs connect to it. You can also make ALL the repeaters AP+WDS, as it's just about how many single radio repeaters you have for any particular connection between an end point and WRT+AP1.

    Further, with your current setup, you can add a few more AP+WDS nodes in between before the wireless starts coming close to being a bottle neck for the 384kbps (~ 0.35Mbps real speed) of your internet connection.
  8. Nox997

    Nox997 LI Guru Member

    thanks for your answer!

    Today, I measured the speed between the gateway and the 4th wrt54gl.

    The result was around 3200kbit/s. I think this is ok, because the quality is around 60 to 70dBm from each node to the other. (or isn't it?)

    btw is the "Afterburner" setting "dangerous" for my wrt54gl and would it boost anything? do wireless clients profit?
  9. Kiwi8

    Kiwi8 LI Guru Member

    What software do u use to measure the speed?
  10. HennieM

    HennieM Network Guru Member

    Your 3200kbps or 3.2Mbps is OK, although I would have expected it a bit higher at ~ -65dBm between all nodes. Check that, on all devices:
    1) You have Frame Burst turned on
    2) If using encryption, use WPA with AES (no encryption is fastest, but...)
    3) WMM off

    Your connection to the 384/64kbps internet however, would be near full speed.

    Afterburner could help if you have all Broadcom Afterburner capable devices right through to your wireless card/adapter, but I'm not sure if Afterburner works in WDS. I have found Afterburner to have just about zero impact in most cases. In fact, Afterburner sometimes appear to slow things down.
  11. Nox997

    Nox997 LI Guru Member


    Thanks for your answer!

    Frame Burst is OFF on all devices - what exactly does this option and "Afterburner" do?

    I'm using WPA Personal with TKIP encryption - should I really change to AES, i.e. would I notice any change?

    WMM is turned OFF on all wrt54gl.

    btw what about boosting the transmit power? Right now, I'm using the default value of 42mW.

  12. HennieM

    HennieM Network Guru Member

    Tom's Networking, aka SmallNetBuilder, reckons TKIP's performance penalty is worse than WEP's - see
    In my experience, AES yields more than 1Mbps over TKIP.

    TKIP uses an all software encryption algorithm, while AES (AES-CCMP) uses a one pass encryption with some hardware help. Thus, AES is lighter on the CPU of the router, and does things a tad faster. (It is also a tad more secure).

    Tx power will most likely not make a difference. The radios in WRTs have an Rx sensitivity of about -70 dBm at 54Mbps, so once a WRT is Rxing at -70dBm or better, the link is, or should be, at 54Mbps (provided there's no or very little noise on that frequency).

    As I understand it, which might not be correct, Frameburst allows one node to send a continious stream of packets to another node, without pausing in between for confirmation of individual frames.
    Speedbooster/Afterburner I have no clue what it does, but it can make a significant difference - see the same article on SmallNetBuilder.
  13. Nox997

    Nox997 LI Guru Member

    thank you!
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