How ac87u and other routers choose channels in auto mode?

[alex-ks]

How ac87u and other routers choose channels in auto mode?
Is it random choice or does it select the channel which is currently more free?

 

[joegreat]

Q: How ac87u and other routers choose channels in auto mode?

A: Very badly!

It's highly recommended to find out which channels are free and select on from the least used area!

 

[sfx2000]

A: Very badly!

It's highly recommended to find out which channels are free and select on from the least used area!

Being that most BHR base software packages are built from 2004 timeframe - they would do a 1/6/11 double scan, then 2,3/7,8/9.10 single scan based on RSSI only - and this was on startup of the chips...

Some of the newer chipsets do a better job - but you'll find this outside of the broadcom realm that many BHR's are built on...

Periodic scans based on the algo below - and this is in linux-wireless...

(busy time - tx time) / (active time - tx time) * 2^(chan_nf - band_min_nf)​

Which is a better approach, IMHO...

 

[RMerlin]

Channels scanned by acsd are actually configurable, at least on the 5 GHz band - never noticed if they also were on the 2.4 Ghz band.

 

[sfx2000]

Channels scanned by acsd are actually configurable, at least on the 5 GHz band - never noticed if they also were on the 2.4 Ghz band.

One would assume that it should be possible, it's basically the same thing... (even the same chips and firmware in many cases, just config and radio front end stuff)

 

[RMerlin]

One would assume that it should be possible, it's basically the same thing... (even the same chips and firmware in many cases, just config and radio front end stuff)

The default nvram setting for the 2.4 GHz band is this, on my US-coded router:

wl0_acs_excl_chans=0x100c,0x190a,0x100d,0x190b,0x100e,0x190c

A lot of parameters seem configurable, assuming acsd doesn't ignore any of them.

wl0_acs_dfsr_immediate=300 3
wl0_acs_fcs_mode=0
wl0_acs_bgdfs_idle_interval=3600
wl0_acs_chan_dwell_time=70
wl0_acs_dfsr_deferred=604800 5
wl0_acs_far_sta_rssi=-75
wl0_acs_excl_chans=0x100c,0x190a,0x100d,0x190b,0x100e,0x190c
wl0_acs_pol=0  100  -20  -15   -18   -1     -10   30   -1    1    1    0
wl0_acs_bgdfs_avoid_on_far_sta=1
wl0_acs_dfs=2
wl0_acs_ci_scan_timeout=300
wl0_acs_bgdfs_ahead=1
wl0_acs_scan_entry_expire=3600
wl0_acs_bgdfs_enab=1
wl0_acs_cs_scan_timer=900
wl0_acs_dfsr_activity=30 10240
wl0_acs_ci_scan_timer=4
wl0_acs_tx_idle_cnt=0
wl0_acs_chan_flop_period=70
wl0_acs_bgdfs_idle_frames_thld=36000

 

[alex-ks]

So in case of ac87u and 5ghz. Is it better to set channel to auto?

 

[joegreat]

So in case of ac87u and 5ghz. Is it better to set channel to auto?

Base on my experience the answer is No!

 

[sfx2000]

So in case of ac87u and 5ghz. Is it better to set channel to auto?

With the 87U and Quantenna on the 5GHz - hmmm... thinking trouble, because Quantenna integration - not that QTN is bad, but it's been a very troubled child in consumer Router/AP integration..

2.4GHz on the broadcom should be fine...

 

[sfx2000]

A lot of parameters seem configurable, assuming acsd doesn't ignore any of them.

ACSD might drive some things into the Broadcom STA driver (and it'll say "yep, ok" and just ignore it)... the header files there and the inner OTP items (based on region info written into OTP) do their best...

 

[alex-ks]

Base on my experience the answer is No!

What software on mac can you recommend to find free channels?

 

[wouterv]

I am not a MAC expert, but a scanner seems to be build in:
http://www.letstalk-tech.com/access-wifi-scanner-macos-sierra/

 

[alex-ks]

Wow. Nice app. Didn't know that there is built in app. Thanks

 

[Mike P]

I see about sixteen 2.4 access points - only of which two could possibly be connected to weakly, but I'm the only 5.0 access point.. 5.0ghz doesn't penetrate walls nor have much range at all.

 

[joegreat]

I see about sixteen 2.4 access points - only of which two could possibly be connected to weakly, but I'm the only 5.0 access point.. 5.0ghz doesn't penetrate walls nor have much range at all.

True words!
But what's the question here or the message you want to convey?

 

[sfx2000]

So in case of ac87u and 5ghz. Is it better to set channel to auto?

The auto-channel methods are proprietary - so Broadcom has one way of doing things, and Quantenna has another...

With 5GHz, interference is less of an issue, due to physics being what they are - the challenge is that the Quantenna radio might, and I say might, support channels that the client chipsets don't depending on regions...

Can't hurt to try it...