2.4Ghz Auto Control Channel selection issues

[b-rubble]

I have noticed that my Auto Selection Control Channel is always 6 and single channeled at 20 mhz. Every time I check my site survey, it continually shows that channels 1 and 11 have very weak or no neighborhood traffic, and 6 has multiple hits with strong signals. The results are similar for active and passive scanning - as well as other wifi analyzer programs. Seems that either 1 + 3 or 11 + 9 should be auto selected at 40 mhz. I am running the Smart Connect function so selecting the correct channels manually is not an option. Both 5Ghz channels do just fine selecting the appropriate channels. RT-AC3200 running Asuswrt-Merlin 380.58. Any help would be appreciated.

 

[cmillar6]

My AC68 does the same thing despite both of my neighbors wifi routers being on channel 6 and their signals are strong in my house. I knew this and had 2.4GHz locked at channel 1 or 11 but I had connection issues on some devices. This is when I switched it to auto and noticed it stuck at channel 6. However, leaving it at channel 6 has made my connection issues go away. I have no explanation for this, perhaps the router really is making the best choice for a channel.

 

[L&LD]

Using channels other than 1, 6, 11 (or 13, where legal) on the 2.4GHz band will cause interference on at least two of the 'control' channels (the ones listed) because the 2.4GHz channels other than the ones listed all overlap. That is bad for all neighboring routers, not just the one we're concerned with.

Using channel 1 + 3 (or 11 + 9) for 40MHz channel width would more than likely give all your neighbors a bad WiFi experience if they left their routers on channel 6, and more than likely you too with worse performance than using only 20MHz channel width on any of the main channels available. This is because when neighboring routers are not on the same channel, they can't sync (time wise) to each other and the 'rogue' router is simply seen as interference. However, when all are on the same channel, they can sync to each other and share the time slices as needed so that the throughput of the networks as a whole is as high as it can be.

5GHz channels don't overlap at all and that is why it is easier for the router and us to see a better 'choice' being made in Auto mode.

I still recommend that you take off the Auto channel selection function and take the time to choose a channel manually instead for both bands and all radios. That way you will be in control of choosing the highest raw transfer rates, the best range and the lowest latency channel too for each band and your specific environment and client devices in use. I haven't found any 'Auto' settings that work better, ever.

I test for max raw throughput from a wired client to the same wireless client (preferably a laptop, plugged into an AC power source and with it's settings set to 'performance'). Ensure you test a few locations and orientations (laptop to router) that are repeatable and imitate your real world usage.

I test for ISP speeds with a good speedtest site like http://www.dslreports.com/speedtest

I also test for responsiveness/latency by loading several large websites after clearing the browser cache and rebooting the laptop at each location too.

It is surprising that the best channel for raw throughput may give the worse latency.

As usual, pick the channel that gives you the best balanced performance for your network usage requirements.

Note that I would avoid using any utility such as inssider when doing the above testing. Not only will it skew the actual results if you do the testing with the utility running, but it will greatly increase the time of the above testing too for no measurable performance increase at all. (Save for having a few more stats available that will not mirror any real world expectations in some/most cases).

 

[b-rubble]

Thank you for the response. I am a confused now. I was under the impression the desire was to be on a channels that ARE NOT shared by other nearby routers. Example: right now I have 1 neighbor on channel 6 (-78db) and one neighbor on channel 8 (-84db) but my router is again auto-choosing to be on control channel 6. There are no nearby routers utilizing any other channels on 2.4ghz. My understanding is that my router should have chosen to be on channel 1 and use 3 as the 40mhz extension channel (as opposed to 11 and 9 since 9 would interfere with my channel 8 neighbor overlapping to 9).

 

[Shamiro]

I´m not sure...but:
Choosing control channel 6 gives you
1 co-channel and 1 overlapping wifi-network in neighborhood.
Choosing control channel 1 would bring
0 co-channel but 2 overlapping networks due to extension channel 5 for 40mhz.

I have to ask something in addition:

You are talking for channel 1+3 and 11+9 for control and extension...
I was believing it´s control channel +4 or -4 for the extension channel? (as any tool I use to check wifi will show it that way)

 

[sfx2000]

Thank you for the response. I am a confused now. I was under the impression the desire was to be on a channels that ARE NOT shared by other nearby routers. Example: right now I have 1 neighbor on channel 6 (-78db) and one neighbor on channel 8 (-84db) but my router is again auto-choosing to be on control channel 6. There are no nearby routers utilizing any other channels on 2.4ghz. My understanding is that my router should have chosen to be on channel 1 and use 3 as the 40mhz extension channel (as opposed to 11 and 9 since 9 would interfere with my channel 8 neighbor overlapping to 9).

Go manual and run on Ch1 - I would disable Wide Channels as there is little benefit and one loses about 3dB Tx power in Wide Mode, and that has a direct impact on range...

BTW - Ch8@-84dB - not a real problem, you see the beacon, but remember that Beacon's are at very low data rate (as such, very high gain), the traffic frames on that AP will not interfere, same with that AP over on Ch6@74dB..

 

[ColinTaylor]

I am running the Smart Connect function so selecting the correct channels manually is not an option.

@sfx2000 But the original point was that he can't manually select a channel.

 

[sfx2000]

@sfx2000 But the original point was that he can't manually select a channel.

Isn't that a side effect of SmartConnect being enabled?

 

[ColinTaylor]

Isn't that a side effect of SmartConnect being enabled?

Yes. That was his point. If you want to use the Tri-band Smart Connect feature you have to rely on the router making the correct channel choice, which it appears to not be doing.

 

[sfx2000]

Yes. That was his point. If you want to use the Tri-band Smart Connect feature you have to rely on the router making the correct channel choice, which it appears to not be doing.

It actually may be running correctly - might be other 2.4GHz sources that are triggering the decision by the 2.4GHz driver to choose Ch6 - most of that is done inside closed source space, and the newer BRCM chips are pretty clever at it.

 

[ColinTaylor]

It actually may be running correctly - might be other 2.4GHz sources that are triggering the decision by the 2.4GHz driver to choose Ch6 - most of that is done inside closed source space, and the newer BRCM chips are pretty clever at it.

Yes I was thinking along the same lines. But then I've noticed over the years that a lots of routers will auto-select channel 6 even when there are other people using it.

I was wondering whether the router is just starting with a default setting (i.e. 6) and unless the co-channel interference is sufficiently strong it just stays there. Just a thought.

 

[sfx2000]

Yes I was thinking along the same lines. But then I've noticed over the years that a lots of routers will auto-select channel 6 even when there are other people using it.

I was wondering whether the router is just starting with a default setting (i.e. 6) and unless the co-channel interference is sufficiently strong it just stays there. Just a thought.

The older chipsets weren't near as clever as the 2nd Generation AC silicon...

 

[kenrok1]

Hi, I realize this is an old thread but it seem like the right place to post this... I've been using RT-AC68U for a while and recently switched to a RT-AC1900P and with either model on any of the last 4 different firmware versions I notice my 2.4Ghz will select channels like 2 or 4 (and jump around too, doesn't stay on one channel) when I set bandwidth to 20Mhz and control channel to auto. I know to play nice we should all use 1, 6, or 11 and whenever I check inSSIDer neighboring wifi is all on 1, 6, 11... so it doesn't make any sense to me. Obvious answer is to set it manually and forget about it, but it would be nice if it worked correctly on auto.