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Tofu13c: WDS Loop, Spanning-Tree Protocol, Dynamic Routing

Discussion in 'HyperWRT Firmware' started by penkert, Feb 24, 2006.

  1. penkert

    penkert Network Guru Member


    I am trying to set up a WDS based network loop between three WRT54G routers (v3.1), all running Tofu13c. So every Router maintains a WDS connection to its two counterparts. If configured correctly this should result in a redundant network architecture and in faster network performance avoiding double WDS signal hops.

    I turned on the spanning-tree protocol option, but for some reason this doesn't seem to stop packets from running in a wireless loop. At least the WLAN LEDs start blinking like mad whenever a request is send from a secondary router (one that isn't hosting the internet connection) and most requests are unsuccessful. I also set the two secondary routers to router mode and fiddled around with the dynamic routing options but nothing seemed to do the trick. Is there anybody who has some experience with such a setup?

    1. What exactly does the spanning-tree option do? There must be something I don't understand...
    2. As I understand dynamic routing options are good for automatically adjusting to changes in the network architecture. So I thought it might help in case one of the WDS links breaks down. However, for this to work reliably wouldn't the main router (the one hosting the DHCP service and the internet connection) also need this capability? But as soon as you set it to gateway mode all the dynamic options are gone.

    I'd really appreciate an answer (or two). :)
    Thanks in advance!

  2. Thibor

    Thibor Super Moderator Staff Member Member

    turn on stp on ALL routers, this will(or should anyway) prevent the loop on your network. don't bother with advanced routing as it's not necessary for your topology. make sure the internet connection type on the 2 remote units is "Disabled" and wireless:SSID, mode, channel and encryption are the same. set mac addresses of the opposite routers(the correct mac is 2 up from the label, ie if the mac on the label ends in 06, the wireless mac ends in 08)
    fill in LAN_Gateway and LAN_DNS in index.asp and disable the firewall and dhcp server on the remote units.
    after that you should be good to go.
  3. NateHoy

    NateHoy Network Guru Member

    Just a clarification to Thibor's post above. The text "0 8 )" without the spaces on forum software like this frequently gets changed to 08)

    So, what he meant, I'm pretty sure, was "the wireless MAC ends in 08" if the wired MAC ends in 06

    Doncha just LOOOOVE auto smiley detection (grin)
  4. Thibor

    Thibor Super Moderator Staff Member Member

    edited my previous post...goddamit!!
  5. penkert

    penkert Network Guru Member

    Hi Thibor!

    Thank you very much for your reply and even more so for the fantastic work you and Tofu do on the HyperWRT firmware! :clap:

    My WDS setup itself was working all right----at least as soon as I took out that redundant link. I also did enable STP on all three routers. I did some more extensive testing today and found out that the problem resided in one of the WDS links running on a very weak signal. (I'm not using directional antennas in my test setup yet.) As soon as the signal strength is good on all three links the network seems to be running like a charm.

    In fact, I was quite surprized by this behavior since I thought the redundancy in this setup would actually prevent the network from failing because of a weak link. That's why it never occured to me before that this might be the cause. But this weak link seems to create some sort of jamming so that even network traffic not using this link (provided the STP is working correctly) comes to a halt. Maybe the network gets flooded with STP packets while the routers are constantly trying to adapt to the changes in the network architecture while that weak WDS links goes on and off!? That's the only explanation I can come up with from my limited point of insight into the inner workings of the firmware and the protocols.

    I'd be really interested in your thoughts on this, even though my initial problem seems to be solved now.

    Thanks once again and salutes to the UK!


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