Advice on how to setup routers

Discussion in 'Tomato Firmware' started by hellwich, Sep 5, 2007.

  1. hellwich

    hellwich Network Guru Member


    So here's what I'm trying to achieve:

    Modem --- Router(1) --- Router(2)

    Additional info:
    - Both routers are WRT54GL
    - Router(1) is the DHCP server
    - Router(1) and router(2) are connected to eachother by a wire
    - Router(1) and router(2) can also see eachother trough wireless
    - Both routers have the latest tomato firmware

    When wirelessly connected with router(2) I'd like that data to be transfered like this:
    Laptop -> wirelessly to Router(2) -> wired to router(1)

    What I want is one network (SSID) troughout my house, so I can walk trough my house without connection problems.

    Can someone give me advice on how to do this? (so I can get the max out of it)

  2. MiseryQ

    MiseryQ Network Guru Member

  3. hellwich

    hellwich Network Guru Member

    Thanks for your fast reply MiseryQ, but alas.. I've tried that before and my router stall and becomes unconnectable (pings timeout etc)...
    Any other advice maybe?
  4. ifican

    ifican Network Guru Member

    WDS would work but from your description you are describing a roaming wireless setup. You simply need to set it up just like you have described. Setup router 1 as a gateway and set your lan to whatever range you want, we will call it Make the lan ip on router 1 and name your ssid whatever you like, then before hooking it up log into router 2 and turn off dhcp and make its lan ip and make the ssid the same as router 1 but use a different channel. Once you have the routers configured plug the modem to the wan port of router 1 and connect the lan port of router 1 to the lan port of router 2. Thats it in a nutshell.
  5. hellwich

    hellwich Network Guru Member

    thanks ifican for your fast reply as well!
    I've did it exactly as you described and it works that way, but now I wonder why they can't be on the same channel.. in the tomato faq MiseryQ refered to it stated that the channel should be the same...

    Don't forget that router(1) and router(2) are also connected to eachother by a wire.. which has, in my opinion, much higher availability and capacity..
    How can I be sure that if I'm connected to router(2) with my laptop that the data is transfered like this:
    Laptop -> wirelessly to router(2) -> wired to router(1)
    instead of:
    Laptop -> wirelessly to router(2) -> wirelessly to router(1)
  6. ifican

    ifican Network Guru Member

    You know thats a question i have wondered myself many times and have never tested. Since you are already setup give it a try and let us know. Though my initial thoughts are that when it moves from one access point to the other, since the mac address of the ap will change it may struggle for a little bit trying to resolve where it actually is suppose to send the traffic. However when it syncs to the other ap on a new channel it immediately knows where to send the traffic. Now you have me curious too.......
  7. ifican

    ifican Network Guru Member

    This is a good question since router 2 is actually acting like a switch. I guess the way you know for sure is you move well out of the range for router1 and into the range of router2, when you dont loose internet you will know it all is working. I suppose you could also see what channel you are on, the channel your adapter is connected to will dictate what access point you are using (that is if you are using 2 different channels and not 1 as alluded too earlier).
  8. hellwich

    hellwich Network Guru Member

    I'm confused as well, because I've read that channels that are on the same frequency interfere with eachother, isn't that also the case with WDS? Or is it the other way around and do they strengthen eachother signal...
    If they would interfere with eachtother wouldn't it be better to disarm WDS? Because it has no use then... (also keeping in mind that WDS cuts troughput in half)

    My goal is that the primary communication line between the routers should be the wired cable, BUT they should also communicate wirelessly = meaning I can walk trough my house with my laptop without losing connectivity.
  9. hellwich

    hellwich Network Guru Member

    I think I found my answer on why my router becomes unconnectable (unpingable).

    If I mY quote the developer of Tomato:

    But avoid creating loop or a situation where there are multiple paths.
    / \
    / \
    #2 ---- #3

    / \
    / \
    #2 #3
    \ /
    \ /
    If you have to do this for link redundancy, try enabling STP in Advanced/Routing to avoid problems.

    That's exactly the problem I had!
    I enabeled STP on the second router and the problem went away. Ofcourse now I'm wondering what STP actually does so I googled a little and I found more info about it here:
    Ofcourse that leaded me to another question: Which line has a higher priority to Tomato? Is it wired? or Wireless? or does it choose the fastest line? (I think this is a question only the developer of Tomato knows)

    To move on to the next question:
    I'm still a little confused about the signal frequency though. I've followed the steps explained here:
    But can somebody tell why the signal frequency must be the same? Because I didn't notice any impact on my network when changing the signal on my second router... but that doesn't mean I don't want to know why it makes no noticable difference...

    And my last question, and then I will stop bugging you guys:
    I configured my network like in the link mentioned above. In the link mentioned above it states that both routers should be in "AP + WDS" mode, BUT again I see no noticable impact on my network if I set my first router to "AP" only. (I left my second router as "AP + WDS")...
    Can someone make this clear to me?

    Thanks all you guys for your fast and clear respones you gave me!

  10. scaredwitless

    scaredwitless Network Guru Member


    What you need to do is disregard MiseryQ's suggestion all together, because he did not take into account (or rather missed) that you have the two routers wired together. With that being the case then setting up WDS would be redundant, so it is not necessary. If you have it turned on turn it back off by setting your routers back to simply being in AP mode.

    WDS is a way of linking the two routers wirelessly, while you've already got them linked wired. The reason WDS needs both radios to be on the same channel is because the two radios need to be able to talk to each other. The system is designed this way so that they take turns talking and thus don't cause interferrance.

    In your wired setup you DO want both radios on different channels (5 channels apart at least, so channel 1, 6, and 11 are the most commonly used) so that they do not cause interferrance with another, because in AP only mode both radios will be talking at the same time.

    So what you want to do is set both routers to the same SSID but both routers on different channels. Because they're on the same SSID your laptop will roam freely between the two signals and just choose whichever signal is currently the strongest at the time.

    So to recap, you want both routers on the same subnet, for example router A being and router B being Router A connected to modem by wan port. Router A and router B connected to each other via cat5 on their LAN ports. Both routers in AP mode. Same SSID on both. Different wireless channels on both. DHCP disabled on router B. And you also need, I think (this is what I've always done) is configure the gateway and DNS IPs on router B to both point to router A (in my example,

    In this setup since WDS is disabled then there is no possible way the two routers are speaking wirelessly so you can rest assured your net connection on router B is coming over the wire.

    To know which router your laptop is currently talking to, well it depends on your wireless driver software, some are more informative than others. If it tells you the channel then that's a dead give away. You can also open both router's web interface in your browsers and look at their device lists. Whichever one is showing your laptop with a signal strength measurement is the one your laptop is currently talking to.
  11. hellwich

    hellwich Network Guru Member

    scaredwitless, thanks for your supurb answer and thanks for your time to write it.

    Atm, I already have my network configured the way you described except for the fact that - as you already said - it's redundant now.

    You say that I can turn of WDS now.. would it strengthen my wireless network if I do that?
    If it doesn't then I leave it the way it is, because only good can come from redundancy.

    If your answer is "yes it would strengthen your wireless network" then should I pick channel 1 and channel 11? (Based on your answer that would be the "best" logical solution, right?)

    Does it have any surplus value if I turn WDS off?

    And as a final question (I hope) why is there a difference between the strength of different channels? I just tested channel 11 for about half an hour and then tested channel 1 for about half an hour and I came to the conclusion that the strenght of channel 1 was greater than the strength of channel 11, even though I haven't got any neighbors with wireless networks (so it couldn't be interfering with my neighbors channel). (For the curious people among us: I tested the wireless strength with a program called Network Stumbler. (
  12. scaredwitless

    scaredwitless Network Guru Member

    Well in this case I don't really think redundancy is better. In my mind it's more unneeded complexity.

    But still irregardless I would completely recommend turning off WDS for one reason: WDS halves your wireless bandwidth. To put it simply that is because of the very fact that in WDS mode the radios are taking turns for transmitting data. (think of it like first router a needs roubter B's radio to be in receive mode via the WDS link, and then router B has to retransmit that data in AP mode to your laptop. You see?)

    So you don't actually need WDS here, and I don't think it's giving you any benefit (but rather has a down side). If you turn of WDS and then set each radio to a different channel you'll have a fully working network, as well as a wireless network providing full bandwidth to your wireless devices.

    Anyway I'm sure there are a lot of explanations why some channels are faster than others, but I don't know all of them off the top of my head. But yes interferrance does come to mind, even if there are no other wireless networks around. Because there are other things that emit interferrance on these frequencies like cordless phones, and microwaves (when on) for example. So that's still possible. Anyway take your pick of channels. I'd probably go with one and 11 just because that sounds like a good pair to me, but it doesn't matter, use 1 and 6 or 6 and 11 if you like. Or if you feel one pair gives you better speeds than the other, go with it.
  13. hellwich

    hellwich Network Guru Member

    Thanks scaredwitless for you help!

    I disabled WDS on both routers and configured both routers to be in AP-only mode with the same SSID on different channels.
  14. MiseryQ

    MiseryQ Network Guru Member

    I'm so giddy with my WDS setup I suggested using it. I missed that the routers were wired together.
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