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Occasional Contributor II
Posts: 17
Registered: ‎12-06-2012

Almost All AP's on the Same 5Ghz Channel

We have 85 Access points in 4 school buildings. 2 Buildings have about 1 AP per classroom/per every other classroom. The other 2 buildings have a few APs spread throughout, so those ones make sense to me.

 

Its the 2 buildings that have APs in adjacent rooms that are utilizing the same 5GHz channel. Any idea on where to look. We only have "default" groups at this point setup, so I'm wondering if its time to look into doing some custom AP groups, etc.

Guru Elite
Posts: 21,587
Registered: ‎03-29-2007

Re: Almost All AP's on the Same 5Ghz Channel

What is your regulatory domain?

Are you running 20mhz, 40Mhz or 80 MHz wide channels?

Who installed and configured your system?



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 17
Registered: ‎12-06-2012

Re: Almost All AP's on the Same 5Ghz Channel

What is your regulatory domain?

Regulatory Domain profile "default"
-----------------------------------
Parameter                         Value
---------                         -----
Country Code                      US
Valid 802.11g channel             1
Valid 802.11g channel             6
Valid 802.11g channel             11
Valid 802.11a channel             36
Valid 802.11a channel             40
Valid 802.11a channel             44
Valid 802.11a channel             48
Valid 802.11a channel             149
Valid 802.11a channel             153
Valid 802.11a channel             157
Valid 802.11a channel             161
Valid 802.11a channel             165
Valid 802.11g 40MHz channel pair  N/A
Valid 802.11a 40MHz channel pair  36-40
Valid 802.11a 40MHz channel pair  44-48
Valid 802.11a 40MHz channel pair  149-153
Valid 802.11a 40MHz channel pair  157-161

 

Are you running 20mhz, 40Mhz or 80 MHz wide channels?

40Mhz on the a-band only.

 

Who installed and configured your system?

Local company (MOSS) initially installed and configured it, however we (in-house) have added additional APs throughout the years.

Guru Elite
Posts: 21,587
Registered: ‎03-29-2007

Re: Almost All AP's on the Same 5Ghz Channel

If you are running 40mhz channels, you only have 4 non-overlapping channels.  If you have access points in every room, each access point can probably see 7 to 8 other access points, which means you will have overlap in every room if you are not using DFS channels.  I would move to 20mhz wide channels so that you do not have adjacent access points on the same channel.  You would do that by going into the ARM profile and change "allowed channels for 40mhz" to "none".  I would also change the arm MAX transmit power in the ARM profile to either 12 or 15 so that fewer access points can see each other.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 17
Registered: ‎12-06-2012

Re: Almost All AP's on the Same 5Ghz Channel

My only concern with lowering the TX power would be that in the other buildings where coverage is limited to begin with.

Guru Elite
Posts: 21,587
Registered: ‎03-29-2007

Re: Almost All AP's on the Same 5Ghz Channel

Do this exercise:

 

For an access point in the dense building, type "show ap arm state ap-name <name of some ap>".  Type the same thing for the building that is not dense, to see how many access points each access point can see.  APs with an RSSI of 20 or more are "relevant", meaning, APs can hear them and clients can roam to them.  That will give you an idea of your density.

 

You can also have a different ARM profile for the sparse building so you have no problems.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 17
Registered: ‎12-06-2012

Re: Almost All AP's on the Same 5Ghz Channel

Thanks for that info. So here is the information without modifying the Max TX at this time:

 

High Density Building (1st floor AP tested - 2nd floor APs start with a "2"):

AP-HHS Rm1110 W23:10.1.9.10:6:15:20.5-Edge:enable : Client Density:75
Neighbor Data
-------------
Name             IP Address  SNR  Assignment  Neighbor Density
----             ----------  ---  ----------  ----------------
HHS RmW2117 W19  10.1.9.40   25   6/18        51/64/68/79
HHS Rm1108 W8    10.1.9.32   12   6/12        46/99/61/46
HHS Rm2108 W12   10.1.9.38   28   1/12        47/58/62/81
HHS 1113 W3      10.1.9.20   26   1/18        52/79/69/65

AP-HHS Rm1110 W23:10.1.9.10:161:18:19-Edge:disable : Client Density:2
Neighbor Data
-------------
Name            IP Address  SNR  Assignment  Neighbor Density
----            ----------  ---  ----------  ----------------
HHS Rm1112      10.1.9.12   13   161/12      2/5/100/40
HHS 1113 W3     10.1.9.20   8    161/15      1/6/50/16
HHS 2106 W20    10.1.9.66   8    48/18       0/8/0/0
HHS Rm2108 W12  10.1.9.38   12   165/18      0/1/0/0

Low Density building:

AP-SES Rm6115 W1:10.1.9.80:1:18:20.5-Edge:disable : Client Density:2
Neighbor Data
-------------
Name                       IP Address   SNR  Assignment  Neighbor Density
----                       ----------   ---  ----------  ----------------
SES South Hall W3          10.1.11.104  17   1/20.5      1/3/50/33
SES Rm6550 W10             10.1.31.7    13   6/18        0
SES Rm6113 W2              10.1.11.175  32   11/20.5     1/1/50/100
SES Hall Outside 6138 W16  10.1.11.53   7    1/20.5      0/3/0/0
SES West Wing Hall W9      10.1.11.138  6    11/12       0/1/0/0

AP-SES Rm6115 W1:10.1.9.80:161:18:19-Edge:enable : Client Density:0
Neighbor Data
-------------
Name               IP Address   SNR  Assignment  Neighbor Density
----               ----------   ---  ----------  ----------------
SES Rm6113 W2      10.1.11.175  10   161/19      0
SES South Hall W3  10.1.11.104  6    161/18      0
Guru Elite
Posts: 21,587
Registered: ‎03-29-2007

Re: Almost All AP's on the Same 5Ghz Channel

Also, please take a look at the  RF and Roaming Optimization for Aruba 802.11ac Networks guide here:  http://community.arubanetworks.com/t5/Validated-Reference-Design/tkb-p/Aruba-VRDs for much more detailed information.

 

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 17
Registered: ‎12-06-2012

Re: Almost All AP's on the Same 5Ghz Channel

I should also note that all of our APs are AP125's. We currently don't have any AC units.

Guru Elite
Posts: 21,587
Registered: ‎03-29-2007

Re: Almost All AP's on the Same 5Ghz Channel

The principles are the same.

To answer your main question, if you are running 40 MHz channels, at that density you do not have enough channels. You should run 20 MHz channels to avoid overlap.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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