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HowTo: Add Wired Ethernet WiFi Mesh Bridges to your Network

Discussion in 'Tomato Firmware' started by ooglek, Jun 18, 2009.

  1. ooglek

    ooglek LI Guru Member

    I wanted to put multiple WiFi routers on my home network, but have them in a Mesh so my wireless clients could switch seamlessly between Access Points, while having the data backhauled to the gateway or Internet connection via wired Ethernet, not via WiFi as many guides out there offer. Using wired Ethernet, you avoid reducing your WiFi throughput, while still being able to cover a larger footprint. Here's how I did it. Credit to narzy @ anandtech forums for posting the how-to. I've rewritten it for a newer version of Tomato Firmware.

    How to set up your secondary WiFi routers as wired WiFi Mesh bridges

    These settings allow you to plug your WiFi routers into your LAN and use the WIRED network to backhaul data, rather than the WiFi network that WDS and Wireless Ethernet Bridge wireless settings do. WDS and Wireless Bridging are extremely useful for extending your network wirelessly, but the downside is that you lose precious wireless bandwidth by forcing your wireless client data (laptop) to be retransmitted wirelessly to the next AP. In THIS configuration, the data is sent via the WIRED network, while still extending your wireless network coverage in a seamless way. You don't need "Wireless Ethernet Bridge" or WDS or any other wacky WiFI settings. Effectively, you are changing your WiFi device from a router to a bridge, putting clients connecting to this router on your local Network, and not NAT'ed behind it.

    1. In the Tomato control panel click Basic > Network

    2. On the Basic Configuration page under WAN / Internet set the following:

    WAN / Internet
    Type: Disabled
    Use WAN port for LAN: [x]

    This disables DHCP by default on this router (at least in Tomato Firmware 1.25), thus eliminating step 4 from the original page above. DHCP will now be handled by your primary gateway router (assuming you have DHCP enabled on your network somewhere).

    3. Under LAN set the following:
    Router IP Address:
    This is the IP address for this router. It usually defaults to or You will want to change it to or another unused static IP within your LAN netblock.
    Subnet Mask:
    Default Gateway:
    This is the IP address of your gateway device that connects directly to the Internet. or are likely candidates for this value.
    Static DNS:
    DNS server to use. Use your Gateway IP if your Gateway router runs a DNS caching service (which it is if it is running Tomato Firmware). If not, use your ISP's DNS servers, or use OpenDNS. http://www.OpenDNS.com/

    4. Under Wireless set the following:
    Enable Wireless: [x]
    Wireless Mode: Access Point
    B/G Mode: Mixed *
    SSID : YourSSID *
    Broadcast: [x] *
    Channel: 11 * [1]
    Security: WPA Personal *
    Encryption: TKIP/AES *
    Shared Key: SuperSecret *
    Group Key Renewal: 3600

    * NOTE: If you want wireless clients to seamlessly switch between your main and secondary routers, select the same values as your primary main router wireless settings for: B/G Mode, SSID, Broadcast, Security, Encryption, Shared Key. The Channel can, and in some cases should, be different, but leaving them the same is OK too. When the settings are the same on both/all routers, the wireless client MAY switch seamlessly between the strongest one at the time, OR will switch to the other when the router it is associated with disappears or loses signal. The values above are an example configuration only, you may change them as you see fit.​

    5. Click Save at the bottom of the screen.

    You can choose a different SSID for this secondary router if you like, but then you lose the value of the "mesh" that this configuration offers. Matching the same AP settings as your main router allows clients to easily switch between APs without changing configuration.

    Credit goes to http://forums.anandtech.com/messageview.aspx?catid=36&threadid=2164169 for inspiring me to write this up.

    [1] Channel selection is important! Most WiFi channels overlap each other, which can lead to interference problems, which may reduce your throughput. Only channels 1, 6 and 11 in North America do not overlap with each other. It is best to use one of these three channels. http://en.wikipedia.org/wiki/802.11
  2. Kibe

    Kibe LI Guru Member

    Useful information on this guide.

    I had to do a lot of research when I decided to do this so I think this should get a "stick".
  3. SgtPepperKSU

    SgtPepperKSU Network Guru Member

    I think you will get much better wireless performance (but won't lose the "seemless" switching) if you choose different channels on each router. Otherwise, they will be "fighting" with each other over who gets to use the channel. Also, the connected computers can make better decisions on which router to connect to. They will still choose the one with the best signal, but it won't constantly flip back and forth as can happen with the same channel.
    crashnburn likes this.
  4. bripab007

    bripab007 Network Guru Member

    SgtPepper's right...everything I've read/heard recommends setting different channels for each of the Wi-Fi APs. Also, the Wi-Fi client software dictates how often it'll check signal strength and jump to another AP. On Mac OS X, for example, it seems to hang on to an AP for an extraordinarily long time before switching over to a stronger AP.
    crashnburn likes this.
  5. Vezado

    Vezado Addicted to LI Member

    I was always under the assumption that this was true, but myth #8 of the globalknowledge whitepaper on 802.11 (here) seems to say the opposite and states that wireless networks were actually designed to share channels, but it is less than ideal as the bandwidth is reduced.

    I do agree that the access points points should be on different channels, so long as they just alternate between 1, 6 & 11 and don't try to use channels in between.
  6. SgtPepperKSU

    SgtPepperKSU Network Guru Member

    Yeah, that's actually what I meant. I didn't mean using channels 1,2,3 for instance, but 1,6,11. Good point.

    When I said they "fight", I put it in quotes for the particular reason you said. I hear a lot that they would see each other as interference, but I've always thought that they would "negotiate" (even that just means waiting for an open moment) use of the channel. So I tried to use a word that would cover both scenarios (either way, it was best to use different channels, so I didn't worry about it). Seems the page you linked has confirmed my suspicions. Thanks for the link!
  7. ooglek

    ooglek LI Guru Member

    This was my experience just now with my 2007 MacBook Pro (still running 10.4.11 until Snow Leopard is out). Tomato showed a Quality signal of 3, RSSI of -90dBm and still wouldn't switch, though I wasn't that close to the other router either.

    I've updated the HowTo to reflect both how the client MAY respond to this setup (which includes the OSX caveat that you mention bripab007), as well as removing the Channel from the matching config settings portion of the notes, thanks to your comments!

    When you say "1,6,11" you mean if you have 3 WiFi APs, put them as far apart in the wireless spectrum as possible, and in this case that means Channels 1, 6 and 11. For me, 1, 6, and 11 are pretty crowded in my neighborhood, and since I only have 2 WiFi APs, I'm using Channels 3 and 9. If you have some information on why Channels 2-5 and 7-10 are somehow bad or undesirable, share!

    On a slightly unrelated note, I updated my Buffalo WHR-G54S with the v1.25 ND software, applied the Intel 2200BG fix [1] (nvram set wl_reg_mode=off ; nvram commit ; reboot ; MacBook Pro wouldn't associate without that fix), and did a speed test. Before with plain 1.25, I got just shy of 10Mbps. After v1.25, I was able to do just shy of 20Mbps (my Gateway connection speed). Pretty significant improvement in speed! Excellent.

    [1] http://www.linksysinfo.org/forums/showthread.php?t=60509
  8. Vezado

    Vezado Addicted to LI Member

    It's not that 1, 6 & 11 are far apart but that they don't overlap. Assuming you stick to channels 1-11, the only way to get three non-overlapping channels is to use 1, 6 & 11.
    If you try using an intermediary channel in an area of strong 1, 6 & 11 channels, your connection will suffer because of interference from the overlapping portions. If you choose channel 1, 6 or 11 then devices will work together to share the channel rather than outright interfering with eachother, as i understand it. You won't get performance as high as you would on a totally clear channel, but the general consensus seems to be that the losses from channel sharing are less than the losses of interference.

    I would imagine, purely guessing here, that as the strength of the neighboring 1, 6 & 11 APs goes down past a certain strength that using 3 & 9 would start to become the better option, but again i'm purely guessing. I don't know how low the signal would have to be before interference is not an issue.
  9. ooglek

    ooglek LI Guru Member

    Selecting Channels

    Awesome post Vezado! Here I am a geek, and I didn't know about the overlapping frequencies problem.

    Your post leads me to ask one other question. For someone in a residential neighborhood or a corporate office park, where you have multiple WiFi routers all running, what is the best course of action? Obviously you can control the channels on your own network to eliminate interference by choosing channels 1, 6 and 11, but your surrounding WiFi citizens don't really give you any control, so you have to work around them.

    Using my situation as an example, I have two APs, one (AP#1) in my basement near the back of my house, one (AP#2) in my 2nd floor office at the front of my house. AP#2 can see 5 neighbor wifi routers; 4 are on channel 6, with the strongest signal at -80 dBm, and 1 on channel 1 at -88 dBm. Obviously I want to stay away from Channels 2-10, since they all overlap with channel 6. So it would seem that my best choices for my two routers are channel 1 and 11.

    Given my two APs, AP#1 that cannot see any other APs but AP#2, and AP#2 that can see 4 APs on Channel 6, 1 AP on Channel 1, rate these Channel Selections:

    1. Run AP#1 on Channel 1, AP #2 on Channel 11
    2. Run AP#1 on Channel 3, AP #2 on Channel 9
    3. Run AP#1 and AP#2 both on Channel 11
    4. Run AP#1 on Channel 6, AP#2 on Channel 1 or 11

    My guess is #1. Since AP#1 cannot see anything but AP#2, any channel is fine. Since AP#2 sees 5 WiFi routers but none on Channel 11, then AP#2 goes to Channel 11. Since 11 overlaps with Channels 7-10, AP#1 can go on any channel 1-6 to avoid interfering with AP#2. Channel 1 is least likely to get interference from a Microwave, so Channel 1 is the best for AP#1.

    Let's say there was no way for me to avoid interference on AP#1. What's the downside of sharing channel 1 with one other AP? What if there are 2, 3 or more on that channel? Is the downside of sharing a channel better than the interference of channel 6 on Channels 2-10? Overall, assuming 4APs each on channels 1, 6, and 11, is it better to share a single frequency with 4 other APs, or better to use Channel 3/4/8/9 and overlap frequencies with 8APs only partially?

    Would love some independent confirmation of my thinking.
  10. Vezado

    Vezado Addicted to LI Member

    1) I think your reasoning is sound, the best option appears to be #1.

    I don't fully know the consequence of channel sharing, if someone more knowledgable can chime in with more info that would be great. Want to do some testing for us? :)

    It could be an outright division of the bandwidth (1/2 speeds for 2 APs, 1/3 for 3, etc.) or maybe it is a more intelligent system that kind of "load balances" the traffic so that an idle AP sharing a channel has little impact. Channel sharing is something i only recently heard about (see above whitepaper) so i can't really answer your question.

    As for which is a greater penalty, i think it will largely depend on the strength of the interference and your proximity to your AP, but like i said before this is just a guess.

    I wonder how close the APs must be before channel sharing takes effect. If an outside AP is just barely detectable but using the same channel, will they try to share it or will they attempt to function as if the other wasn't there? I really don't know.
  11. David Yost

    David Yost Networkin' Nut Member

    I followed your directions and it seems to be working... but I have a slight problem. I can't seem to access the secondary/extender router. I set the ip to & can't even ping. If I go under the "Device List" on the primary it doesn't even seem to be registered as being connected.

    Any ideas?

    Note: I did setup with two SSID's (WiFi1 & WiFi2), but I don't see how this should change anything. I have tried to ping both from WiFi1 & WiFi2.
  12. Monk E. Boy

    Monk E. Boy Network Guru Member

    When I've setup meshes in the past, I had to set the secondary router into DHCP Forwarder mode, so the secondary forwarded DHCP requests to the primary. However that was done with DD-WRT and I haven't done one with Tomato, but the concept should be similar. Make sure DHCP is setup in forwarding mode (if it's not an option, make sure it's disabled) on the secondary and that the cable running between the two is connected to a LAN port on each end.
  13. crashnburn

    crashnburn LI Guru Member

    No testing needed. :p For that you have to read and understand MAC (Medium Access Control) mechanism for WiFi - CSMA - CA (Collision Avoidance).
    Its basically the PROTOCOL or Manners that which all devices will use a common AIR space. Everyones shouting and everyones listening so you have to do it in turns and AVOID doing it at the same TIME. If two people shout at the same moment, the listener cant discern the message.. i.e. Collision.

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