Location Services

While roaming is great, we have a couple of situations where we have a fixed location client that seems to have a hard time choosing between an AP.  It is in a lobby area that has visibility to a number of APs that are nearby, and AirWave shows it basically jumping between them.  The client is a digital signage PC, so when it hops, its browser sometimes displays an ugly "page not found" message instead of refreshing the signage.  We've read a number of topics about roaming, client match, etc. but wondered if it was possible to go the other direction and force this client to be "sticky".  Thanks!

Some wireless client utilities/drivers allow you to lock the client to a BSSID. 

The only other way would be to create an SSID on a single AP and associate the client to it. 




Thanks, 
Tim

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@jwhitaker@transy.edu wrote:

While roaming is great, we have a couple of situations where we have a fixed location client that seems to have a hard time choosing between an AP.  It is in a lobby area that has visibility to a number of APs that are nearby, and AirWave shows it basically jumping between them.  The client is a digital signage PC, so when it hops, its browser sometimes displays an ugly "page not found" message instead of refreshing the signage.  We've read a number of topics about roaming, client match, etc. but wondered if it was possible to go the other direction and force this client to be "sticky".  Thanks!

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jwhitaker,

 

Is this indoors?  What is the power of your access points in the area?  What version of ArubaOS is this?

Indoors, ArubaOS 6.4.2.3, there are AP-205s and AP-115s nearby, I see power settings of 19, 21, 24 around.

#AP205

Change the arm max power to 18. That should reduce the bouncing.

We have not had good luck in limiting the power in that way, especially on the minimum power side.  We tried 12/18 and had clients 20 feet away that couldn't connect.  We can give it a shot again in this area, but it has been a somewhat frustrating experience for us trying to retool to what appears to be a requirement to have a more dense AP deployment to handle the same load that our Cisco gear was handling before.  I'm sure we have APs in locations that are not optimally distanced, but it has been a challenge trying to work through.  Thanks.

 

If your only issue is with that specific device, you should  should start by surveying that area to see exactly what coverage you are getting.

You should also look at the RF utilization using the controller's dashboard to see if high utilization is keeping that display sign from connecting effectively.

 

The problem with having an access point at the power of 24 is that it is incredibly high.  The AP power, dBm is logarithmic, so every 3 clicks you go up, effectively doubles the power.  Having power that is too high is the biggest reason for (1) roaming and (2) having clients that bounce between access points.  In addition if the power is too high on the access points, clients end up talking to access points that probably cannot hear them and that will decrease performance considerably.

 

Take some time to measure what is in that area to get a full picture of your issue.

 

 

 

• 0dBm = 1mW
• 10dBm = 10mW
• 12dBm = 15mW
• 18dBm = 63mW
• 20dBm = 100mW
• 21dBm = 125mW
• 22dBm = 158mW
• 23dBm = 199mW
• 24dBm = 251mW

 

As a reference iphone5 = 13dbm max output

Thanks for your reply.  If ARM is in play, why would it bump the power up to a high level like what we see?  Would that indicate that we don't have enough APs in the area?  How does ARM decide on a power level?  Understanding that may help us get our head around the issues we've had.  

ARM will not put it over your ARM max tx that you set....  It decides on a power level based on how many access points in the area are on that channel.  If it is on max power, it could mean that you do not have enough density.  You need to double-check it with inssider and possibly a site survey.  The access point could have obstructions so that it cannot see other access points, and that would make it raise the power.  The power should never be over 20 if you have decent density. You also would not want the power to end up at so many times more than client max output.

We surveyed and ended up placing another AP in this area. Our philosophy is changing to "density ain't a bad thing". :) Thanks for the info.