Wireless Access

I've found several areas of our campus where 2.4GHz is so busy that it's unusable.  Today was a perfect example of that.  We had roughly 20 employees in a conference room connecting to a single AP105 in the room.  All of the clients were only b/g capable.  I received complaints that their wireless was so slow they couldn't use it effectively.   Channel utlization was around 85%.  Even after hours with only a few clients on the floor, channel utilization is still around 80%.  I started to examine other APs on the floor, there are 4 others, and noticed that they're all on channel 1.  Then I looked at the floors above/below and find that most of the b/g radios are on channel 1 as well.  I enabled spectrum analysis on the conference room AP and found that channels 6 and 11 had far less utilization.  So I rebooted the AP, thinking that ARM would see how busy channel 1 is and select 6 or 11, but it chose 1 when it came back up.  After looking at all of the APs on campus, channel 1 is by far the most selected channel.

 

ARM seems to prefer channel 1 even in cases where 1 is the most heavily utilized channel.  Is there any reason why this would be and any way to get better channel selection out of ARM?

Need much more information about your environment.  Do the access points see each other well from room to room and floor to floor?

 

Make sure ARM is set to all of the defaults and you do not have spectrum load balancing on.  Also, if you have Client Aware on, they will never change channels while clients are associated.  Make sure it is off.

 

Read the ARM supplement here:  http://community.arubanetworks.com/aruba/attachments/aruba/70/1204/1/ARM+Doc+Supplement.pdf

 

 

ARM is at defaults. Spectrum load balancing is disabled.

Each floor is roughly 10k sq ft, with 5 APs on each floor.

What would be the best way to find out how many neighboring acces points an ap can see?

Is it really advisable to turn off client aware? My concern is that disabling it will cause more client disconnect issues than we're already seeing (separate issue but worth mentioning).

Is client aware off?

 

show ap monitor ap-list ap-name <name of ap>

Client aware is enabled.

Well, that means the access points will NEVER change channels while clients are associated.

 

Please turn it off so that the access points have a chance to settle.

 

The APs should be settling in the evening as employees leave. Most APs don't have clients associated after hours so the APs typically change channels at night. I thought this would be good enough.

Honestly, I have reservations about allowing APs to change channels at any time. Don't I have to be concerned with clients getting disconnected due to ap channel changes? I've never had this feature disabled so I would like to know what to expect.

You should be fine, as long as the clients don't do voice.  If there is a chance of it, enable Voice aware.

I've been able to get channel utilization below 20% after modifying the 802.11g basic & transmit rates.  I followed TAC's top 10 tips for clipping lower data rates, but realized after implementing the changes that they're meant for VoWiFi devices. 

 

Here is what is suggested and what was implemented:

 

g-basic-rates 5 6

g-tx-rates 5 6 9 11 12 18 24 36 48 54

I assumed this removed 802.11b rates, but I'm not sure that's the case.  Can someone please let me know the proper basic rate and tx rate values should be set to effectively remove 802.11b capabilities?

 

Also, I'd like to mention that I noticed frame check sequence errors go up on 2.4 after I made the rate changes.

I was able to find my answer:

 

g-basic-rates 6

g-tx-rates 6 9 12 18 24 36 48 54