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WNDR3700 Wireless N Not Working

Posted: Thu Jan 19, 2017 9:17 pm
by pbix
I have a WNDR3700v2 and have notice that in v1.9.1 the wireless settings for 'N' mode don't seem to be correct.

When I set the 2.4ghz wireless setting for b+g+n I and the 40 over/under setting to anything I do not get a valid N wireless configuration.

I see hwmode set to '11g' instead of '11ng'. Also I think that there is no need to have this over/under 40Mhz pick. Simply setting htmode='HT40' is all that is needed now.

Has anyone else notice this on this or any other N router?

Re: WNDR3700 Wireless N Not Working

Posted: Thu Jan 19, 2017 9:23 pm
by Lantis
pbix wrote:I have a WNDR3700v2 and have notice that in v1.9.1 the wireless settings for 'N' mode don't seem to be correct.

When I set the 2.4ghz wireless setting for b+g+n I and the 40 over/under setting to anything I do not get a valid N wireless configuration.

I see hwmode set to '11g' instead of '11ng'. Also I think that there is no need to have this over/under 40Mhz pick. Simply setting htmode='HT40' is all that is needed now.

Has anyone else notice this on this or any other N router?

There has been some changes since Barrier Breaker (and the associated hostapd)
"11ng" is no longer a valid mode.
"11g" is the equivalent selector.
To get the "N" working, you set the HTMODE to HT20/40/40+/40-
HT20 being 20mhz, 40 being auto selection of above or below channel, and the 40+ and 40- being the respective additional channel selectors.

So while we can just leave it as HT40, for the moment the way the interface is coded, having it as 40+ and 40- is ok.

To get regular B+G mode, you select "11g" as before, and set HTMODE to "NONE"

Similar changes were applied to the 5GHz spectrum where "11a" is now the correct selector.

I rewrote a lot of the config generation for this section so if you find something that doesn't work or doesn't follow protocol please let me know.

Re: WNDR3700 Wireless N Not Working

Posted: Fri Jan 20, 2017 1:06 pm
by pbix
Thanks for the great response on this.

With this router I cannot seem to get a 300Mbps connection. The connected hosts screen never shows above 130Mbps for my computer. And I wonder if the second channel is even working. What is the best way to tell that everything is working properly?

Re: WNDR3700 Wireless N Not Working

Posted: Fri Jan 20, 2017 4:00 pm
by Lantis
Quickest way is to use another device and do a spectrum scan and check if the router is truly transmitting a 40MHz wide channel. Due to standards and policies I collectively refer to as "The Nice Neighbour" policy, you can't do 40MHz if it will interfere with another network over a certain threshold.

I believe there's also a message about this in dmesg, something like "unable to start 40MHz channel due to interference".

The option "noscan" could be useful in your testing here.
Note it's attached warning.
https://wiki.openwrt.org/doc/uci/wireless

Re: WNDR3700 Wireless N Not Working

Posted: Fri Jan 20, 2017 8:19 pm
by pbix
The channel I am trying to use is 8 and I think the pairing is then 4 I think.

The noscan option did indeed cause the second channel (4) to start operation. There are other signals in the vicinity although they are very weak and none of them are channel 4. I guess they are enough to block the setup of the second channel.

There is no message of any kind in logread or dmesg that I could see.

So now I have to figure out if there is any way to squeeze in to the spectrum here or just live on the wild side with the noscan option.

Thanks again. Nice to have someone around the forum who knows this stuff.

Re: WNDR3700 Wireless N Not Working

Posted: Fri Jan 20, 2017 10:22 pm
by Lantis
http://www.smallnetbuilder.com/wireless ... ghz-part-1

This site has a great explanation and the associated equation.

And no dramas :) always happy to help

Re: WNDR3700 Wireless N Not Working

Posted: Sat Jan 21, 2017 2:20 am
by ektus
pbix wrote:The channel I am trying to use is 8 and I think the pairing is then 4 I think.

The noscan option did indeed cause the second channel (4) to start operation. There are other signals in the vicinity although they are very weak and none of them are channel 4. I guess they are enough to block the setup of the second channel.

There is no message of any kind in logread or dmesg that I could see.
On my Archer C7 V2, the relevant lines in logread show this:

Code: Select all

Sat Jan 21 07:14:52 2017 daemon.notice netifd: radio1 (17160): wlan1: interface state UNINITIALIZED->COUNTRY_UPDATE
Sat Jan 21 07:14:52 2017 daemon.notice netifd: radio1 (17160): wlan1: interface state COUNTRY_UPDATE->HT_SCAN
Sat Jan 21 07:14:53 2017 daemon.notice netifd: radio1 (17160): 20/40 MHz operation not permitted on channel pri=13 sec=9 based on overlapping BSSes
To obtain this information, I installed the extension "webshell" and issued the command "wifi" to restart wireless, followed by "logread" to show the current message buffer.

Regards
Ektus.

Re: WNDR3700 Wireless N Not Working

Posted: Sat Jan 21, 2017 10:41 pm
by Lantis
Thanks for posting that snippet. That is exactly the line i was trying to quote (from memory :P)