1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

WiFi Channel cannot be set

Discussion in 'Tomato Firmware' started by Chris Amidon, Jul 2, 2013.

  1. Chris Amidon

    Chris Amidon Reformed Router Member

    I have an E4200 and I'm running 1.28.0000 MIPSR2-110 K26 USB Mega-VPN. The issue that I'm having is that when I go to Basic > Network and configure the SSID for eth1 and configure the channel for a specific channel, it appears to work. I always do a scan first to make sure no-one else is using the channel.

    However, when I go to Status > Overview and check the channel for eth1, it lists a completely different channel from the one that I selected. I even tried rebooting the router and that caused the channel to be changed, but not to the channel I selected.
     
  2. Malitiacurt

    Malitiacurt Networkin' Nut Member

    Did you set the channel width to 40Mhz? Might be showing both channels in the UI or the average, can't remember the default behavior for showing channels regarding 40Mhz in each mod and dd-wrt.
     
  3. Chris Amidon

    Chris Amidon Reformed Router Member

    The channel width is indeed currently set to 40Mhz.
     
  4. koitsu

    koitsu Network Guru Member

    Don't do that.
     
  5. gutsman7

    gutsman7 Networkin' Nut Member

    nvram set wl0_channel=1. Put this in your init script box with your desired channel, save , then reboot.
     
  6. Planiwa

    Planiwa LI Guru Member

    Considering the OP's problem:

    If the wireless driver is allowed to switch channels, it may do so frequently (more than once a second), and for reasons that are difficult to fathom. For example:

    Code:
    Jun 29 13:00:15 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 13:00:15 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:00:15 Router user.warn kernel: COEX: downgraded chanspec 0x2e09 to 0x2b0b: channel 6 used by exiting BSSs
    Jun 29 13:06:21 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 13:06:34 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:15:15 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:30:16 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:37:47 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:38:00 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:38:13 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:38:26 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 4 used by exiting BSSs
    Jun 29 13:38:39 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: ext channel 6 used as ctrl channel by existing BSSs
    Jun 29 13:40:07 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:40:47 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: ext channel 6 used as ctrl channel by existing BSSs
    Jun 29 13:41:22 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 13:42:22 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: ext channel 6 used as ctrl channel by existing BSSs
    Jun 29 14:00:01 Router syslog.info root: -- MARK --
    Jun 29 14:00:16 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:00:32 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 14:00:32 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:01:22 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:01:22 Router user.warn kernel: COEX: downgraded chanspec 0x2e09 to 0x2b0b: channel 6 used by exiting BSSs
    Jun 29 14:01:35 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:02:57 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 14:02:57 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:03:57 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 14:04:27 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 14:04:40 Router user.warn kernel: COEX: downgraded chanspec 0x2e05 to 0x2b07: channel 1 used by exiting BSSs
    Jun 29 14:04:40 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs
    Jun 29 14:06:37 Router user.warn kernel: COEX: downgraded chanspec 0x2e08 to 0x2b0a: channel 3 used by exiting BSSs 
    These messages do not inspire confidence in the work of the driver programmer(s).
     
  7. Marcel Tunks

    Marcel Tunks Networkin' Nut Member

    Does that indicate that the channel is changing, or just that other factors (e.g. neighboring wifi) that should influence chanspec are being monitored by the driver?

    I have no idea how the driver automatically sets these variables, or whether the warning is related to interference mitigation algorithms. There was a comment in another forum involving Asuswrt that these messages disappear after setting channel number, channel width, and control channel manually, which are the chanspec variables. Does that hold true for Tomato? (at work, can't test it myself)
     
  8. Monk E. Boy

    Monk E. Boy Network Guru Member

    With 40Mhz channels enabled on 2.4Ghz, you have a choice of using channels 1-8 or channels 4-11. If you want to use a smaller range of channels (for example channels 1-3 - AKA "channel 1", or channels 4-8 - AKA "channel 6") then you need to use 20Mhz mode.

    With 40Mhz mode you are essentially only leaving one channel available for everyone else within 2.4Ghz range to use. Unless you're sitting in the middle of a large swathe of property with you as the only tenant in that area, it's extremely unlikely that you'll be capable of using 2.4Ghz 40Mhz channels. Unless you don't mind screwing over everyone else within range, in which case you can certainly go right ahead... though in many cases you'll end up with worse performance than 20Mhz due to interference.
     
    koitsu and Marcel Tunks like this.

Share This Page