Wireless Access

We're looking to improve 2.4 channel utilization in a number of buildings, however for the moment we're focusing on one.

Had our engineers come out & take a look & as a result, we've decreased 2.4ghz power (6-18dbm) in the arm profile. Noticed some improvement in the # of band steerable clients listed (show ap associations), however not all band steered clients were connected @ 5ghz; so it appears as if it as it says, band-steerABLE, not band-steerED. Additionally, noticed a large amount of APs switch to 6dBm power, which we hope helps.

Thinking about implementing mode-aware ARM to turn off some 2.4ghz radios. Would like to try this out as a test & see what the differences will be before using it in production. Any recommendations or experiences would be appreciated. We're thinking about manually shutting off radios & simply use mode-aware ARM to get a recommendation / identification of radios to shutoff. Once again, any recommendations or experiences would be appreciated.

Before we do, wondering if it is possible to tell which of our 2.4ghz clients are capable of 5ghz connectivity? Dunno if it's possible by searching through controller's logs for client beacons or association requests?

May also look at disabling basic rates, but one step at a time.

TIA,

--Raf

You were in the right track in terms of the figuring out if those devices are able to support the 5Ghz band but it will depend on the type of device too .

 

Band steering will try 5 times to steer the device to the 11a but if the is very stubborn and prefers 11g it may not get steer .

 

If you have an ap deployment map with Airwave visual rf or the standalone you could potentially try picking the APs you want to turn off the 11g band and making those Air Monitors and that would allow you to see the impact you could make by disabling those.

 

Disabling the lower rates for 11g is a plus but keep in mind that some devices don't behave very well when these are disable.

 

If you have AOS6.x you can take advantage of the dashboard and this will give you an overall idea :

 

 

 

 

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@Raf wrote:
We're looking to improve 2.4 channel utilization in a number of buildings, however for the moment we're focusing on one.

@Had our engineers come out & take a look & as a result, we've decreased 2.4ghz power (6-18dbm) in the arm profile. Noticed some improvement in the # of band steerable clients listed (show ap associations), however not all band steered clients were connected @ 5ghz; so it appears as if it as it says, band-steerABLE, not band-steerED. Additionally, noticed a large amount of APs switch to 6dBm power, which we hope helps.

Thinking about implementing mode-aware ARM to turn off some 2.4ghz radios. Would like to try this out as a test & see what the differences will be before using it in production. Any recommendations or experiences would be appreciated. We're thinking about manually shutting off radios & simply use mode-aware ARM to get a recommendation / identification of radios to shutoff. Once again, any recommendations or experiences would be appreciated.

Before we do, wondering if it is possible to tell which of our 2.4ghz clients are capable of 5ghz connectivity? Dunno if it's possible by searching through controller's logs for client beacons or association requests?

May also look at disabling basic rates, but one step at a time.

TIA,

--Raf

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If you have band steering on any of your SSIDs, "show ap band-steering clients" will show you 5ghz capable devices.  This list has a cap of 4000? devices, so it will roll over in first in-first out fashion, depending on how many devices you have.

 

I think you are doing it the right way.  You should not really have the TX power of the APs less than 9, otherwise the TX power of the access point will be below that of the clients and cause other issues.  If you set the Min TX power to 6 and there are access points that lower their power to 6, you can turn the Min TX power to 9 and turn on ARM mode aware.  A TX power of 9 would keep the power symetric to your lowest power clients, but still possibly provide enough coverage if Mode Aware is on.  First set the min TX power to 9, and then turn on Mode Aware.  Survey your areas and population to ensure that everyone has decent coverage.  Use 20mhz channels on the 5ghz, if you are not doing that already so you can attempt to have good channel separation.  Last but not least Minimize the SSIDs you are broadcasting and/or only set VAPs to broadcast on bands that will be used.  If all your enterprise clients are 5ghz capable, only broadcast that VAP on 5ghz.  You also might want to broadcast your guest SSID on 2.4ghz only and see if it helps your enterprise SSID.  The metric you need to look at in Airwave if you have it is Channel Utilization on the band of any access point that you are having problems with.  Measure channel utilization before and after your changes to keep score..

Thank you, 

 

Yeah, I found that command in one of the knowledge base articles after a bit more searching.  Didn't know about the 4k cap, which is good to know. 

 

(controller1) # show ap band-steering-clients 

 

5GHz Capable Clients:3071

 

04:54:53:71:e1:00

a8:86:dd:e6:64:00

f4:f5:a5:b3:e2:80

…

 

That command by itself isn't terribly useful.  However, w/ a little bit of cli-fu, we can gather a list of connected 2.4 GHz g clients that are 5 GHz capable. 

 

(controller1) #show ap association phy g | include dragonfly3 

stil-a-05c6  00:1a:1e:20:5c:60  60:c5:47:4b:86:33  y     y      4    20     dragonfly3   431      0x13c0     g    6h:58m:4s       1          WA

stil-5-05a6  00:1a:1e:20:5a:60  b0:aa:36:ff:10:3e  y     y      1    10     dragonfly3   431      0x130e     g    1m:17s          1          WA

stil-8-056a  00:1a:1e:20:56:a0  ec:55:f9:c4:b8:39  y     y      1    0      dragonfly3   431      0x1346     g    1h:31m:46s      1          WA

…

 

Used awk to gather the clients' MAC address. 

 

$ awk '{print $3}' "df3 g clients.txt" > df3_g_clients.txt 

 

Sort both files.  

 

$ sort df3_g_clients.txt > df3_g_clients_sorted.txt

$ sort "5GHz capable clients.txt" > 5ghz_capable_sorted.txt

 

Finally use comm to find the commonalities.  

 

$ comm -12 5ghz_capable_sorted.txt df3_g_clients_sorted.txt  

18:af:61:ee:68:ba

40:0e:85:67:c2:76

5c:0a:5b:a6:f8:bf

5c:0a:5b:f4:09:26

cc:78:5f:1c:d7:34

 

$ wc -l df3_g_clients_sorted.txt 

      60 df3_g_clients_sorted.txt

 

So, out of the 60 clients connected to our enterprise SSID, only 5 of them (according to the output of "show ap band-steering-clients") are capable of 5 GHz connectivity.   I did the same test for our guest network & non-5 GHz network for older devices & came up w/ the same results.  So I assume that the B: Band Steerable flag seen in the output of "show ap associations" is right on, in that those client w/ that flag are 5 GHz capable. 

 

I've read just about all of the HighDensity VRDs & have come up w/ the same conclusions.  

 

"At 5 GHz, the appropriate range is from 15 dBm to 18 dBm."  -  we're actually going to let 5 GHz roam the full range. 

"The 2.4 GHz power range is set from 9 dBm to 15 dBm, then ARM analyzes and determines which 2.4 GHz radios to enable."  - still working on the mode-aware bit. 

 

Out of 66 APs, 19 are currently using 6 dBm transmit power in 2.4 Ghz.  Coverage from VisualRF Heatmaps looks acceptable, and we've already gotten positive feedback from occupants in the building.  

 

We'll look into setting it back to 9 dBm & turning on mode-aware ARM.  I'm actually waiting to hear back from our Aruba team for their recommendations.  Do you recommend simply running w/ mode-aware ARM enabled fulltime or can one enable it for a short while to get an idea of what radios to turn of and then set them to AirMonitors manually?  Additionally, I think we'll need to disable client-aware ARM in order for any changes to take place.  This is something that we're still coming to terms w/ & trying to stratergize what is the best way to do so w/ minimal disruption to clients.  Your views, opinions, & recommendations would be greatly appreciated. 

 

We already use HT20 & HT40 channels on the 5 GHz spectrium.   Guest SSID is already 2.4 GHz only, however we've been told from Aruba that we should consider enabling 5 GHz in Guest.  

 

Yes, we've got Airwave (7.7.1; yeah, I need to upgrade) & we're using it to see Utilization.  We're really happy w/ the RF Capacity tab & we're using it to see before & after channel utilization for all APs in a building / group; although it takes one a while to wrap their head around the top graph's description.  We've started taking screen shots to record before & after results once changes are made. 

 

 

Most of our residence halls have 50% or more of their APs in the 80% Channel Utilization red zone for 2.4 GHz; very few radions over 20% of time over 80% utilziation.  Most of the deployments mimic the "Microcel Reference Design #2 - Low Attenuation" that is described in the Next Gen Wireless Arch for Multimedia-Grade Residence Halls AppNote.   

 

A few other things I'm considering : disabling basic rates in 2.4 GHz (although I hear it may cause issues w/ older clients & gaming consoles), enable local probe request threshold (25 dB), use airtime fairness (either fair or preferred),  enabling broadcast filter-arp & broadcast filter all on the vap profile.  

 

The main thing we're working on now is our identifying which buildings to make changes in given their deployment, utilization, attenuation, making sure we have proper profiles in place for RF & ARM, & deciding on what changes we actually want to make & how to best implement them.  Oh, & as usual; documentation, documentation, documentation.  

 

Thanks,