Users connecting at 2.4GHz and not 5GHz, would could cause this?

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Having an interesting issue where a user will only associate to AP Y at 2.4GHz, this is the AP that their desk is closest to. They will occasionally connect to a different AP, lets call it AP Z, that is the next closest AP to their position. When they associate to this one, they do so at 5GHz. Would interference cause them to not be able to associate to the closest AP in 5GHz?

Thanks
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waz@exp

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Posted 5 years ago

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Andrew MacTaggart, Champ

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Too many variables but the 2.4 Ghz signal is probably stronger from the client perspective, you would need an analyzer to view the RSSI and SNR from the different APs.

2.4 Ghz will travel farther then 5Ghz

try this
Update the wireless card firmware and or drivers
enable band stearing if you would like to urge clients to connect to 5Ghz

We generally disable the lower data rates for B to avoid the CTS/RTS issues in the 2.4 Ghz ranges this will shorten the coverage area as well, but if you have B clients you can't do this.

http://revolutionwifi.blogspot.hk/201...
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Crowdie, Champ

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Other things to consider:

* What 5 GHz data rates are enabled? Beacons are transmitted on the lowest mandatory data rate and, if you have the lowest mandatory data rate too low, some wireless clients can make poor association and roaming decisions. This is a major cause of "sticky" wireless clients that are reluctant to roam.

* What are the maximum 2.4 and 5 GHz radio transmit power settings? I find for indoor use that setting the maximum 2.4 GHz radio transmit power to 14 dBm and the maximum 5 GHz radio transmit power to 17 dBm works well.

Note: The 5 GHz attenuation (gradual signal loss) is greater than the 2.4 GHz attenuation so having a 2.4 GHz radio transmit power lower than its 5 GHz equivalent can go some way to "equalizing" the coverage areas of each radio.

* What is the environment between the wireless client and the access points? Is one access point visible from the wireless client's location while the other is obstructed by walls? Have you placed one of the access points in a corridor or other large open area?
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waz@exp

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Thanks everyone for the replies. I should have probably added a few more details, so I will give a few more specifics that may help to define the problem just a little more. I've inherited this design and I'm making improvements as time goes on. The improvements made have helped to solve issues, but this particular issue has me a little puzzled. This issue is not specific to this one user though, it's not happening to all of my users, just 5 that are placed at various distances from one particular AP. The one I'm using as my example is sitting about 12 feet from the AP, where the AP is mounted on the wall, and he is sitting at the 4 o'clock position if the AP were placed at the center of a clock. All of the users are sitting between 4 o'clock and 6 o'clock in relation to this AP at vary distances that range between 12 and 20 feet.

Andrew, I agree there are a lot of variables at play here, and in this case, the user is definitely receiving a better signal at 2.4GHz. I had disabled 1, 2.2, and 5mbps on 2.4GHz, but then we had to turn 2.2 and 5 back on when this issue started happening b/c these 5 users would lose their association to this AP and 4 of the 5 would not roam to a new AP. When he connects to this AP, his data rate is very slow so I'd have to think that he is picking up the 2.2mbps.

That is a great idea, but I've got band steering enabled. It is working, just not for these 5 clients. They are all running MacBook Pros, we're a 98% Mac shop, and 4 of the 5 users have computers that are less than 2 months old so the drivers are as up to date as possible.

Crowdie, 6 is optional and 9 is basic for 5 GHz. You're are right and I've seen this happen with a different AP where the user was stuck using 2.4 GHz b/c they could achieve the lowest rate of 2.2 while connected to this AP. Turning those lower rates off solved that problem and they would roam to a new AP and stay connected at 5 GHz.

The max power settings box is not checked under the radio profiles for 2.4 and 5 GHz. This APs current power settings are at 3 dBm for 2.4 and 8dBm for 5 GHz.

The environment, overall, is rather interesting. Keeping it short, this is a very open space with employees clustered together based on job assignment. They've found a unique, and frustrating, way to bring power to the clusters though. The users who are having this issue have varying obstacles in their way. The one thing in common is that there is a junction box for electrical power about 2 feet to the 3 o'clock of the AP. As mentioned above, all of the users are sitting to the same side of the AP where this junction box is located. The only hesitation I have is that I have 3 other users sitting in this same zone, between 4 and 6 o'clock that are not having these same issues and are properly connecting at 5 GHz. The only difference is that they are 25 feet away from the AP and not in that 12-20 foot range.

Hopefully this all makes sense and I initially asked the question wondering if this junction box could be causing interference, even though I didn't directly come out and ask the question that way, which is my bad. Could this box be killing the signal in that 12-20 foot distance, but not be causing problems for the 20-25 foot range?
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Crowdie, Champ

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"where the AP is mounted on the wall"

Which model of access point is mounted on the wall. If it is a model with integrated omni-directional antennas (AP20, AP120, AP121, AP320, AP330) it must be mounted facing the floor with the access point parallel to the floor.

" I had disabled 1, 2.2, and 5mbps on 2.4GHz, but then we had to turn 2.2 and 5 back on when this issue started happening b/c these 5 users would lose their association to this AP and 4 of the 5 would not roam to a new AP. When he connects to this AP, his data rate is very slow so I'd have to think that he is picking up the 2.2mbps."

This sounds like a "retry issue". The big question is what is causing the retries. The possible causes include outside non-802.11 interference, a too dense wireless deployment, too high radio transmit powers, etc.

"The max power settings box is not checked under the radio profiles for 2.4 and 5 GHz. This APs current power settings are at 3 dBm for 2.4 and 8dBm for 5 GHz"

That 2.4 GHz power settings seems extremely low for an Aerohive access point. Was the 3 dBm power setting manually set or is the radio management selecting it? If the radio management is selecting it how dense is your access point deployment?

If you complete a spectrum analysis on the affected access points what do they report?
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waz@exp

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Crowdie...thanks for all of the information.

I do have a quick question, if you don't mind, about the placement of the APs. We are using AP330s in this main room that I'm describing. We have an AP on the North, South, East, and West walls...so 4 total. Each is AP mounted 15 feet off of the ground in the center of the wall, facing inwards towards the middle of the room. When the design of the wireless infrastructure was put together, the original person who created and implemented it worked with someone from Aerohive. They had ok'd the placement of the APs in this fashion, in your opinion, would it be better to have them suspended from the ceiling?
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Crowdie, Champ

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The AP330 access points should be mounted parallel to the ground. If sounds like your installation has the AP330 access points mounted flush against a wall perpendicular to the ground. Does this sound correct?

With four access points covering a "main room" and there only being three non-overlapping channels in the 2.4 GHz spectrum how are you avoiding co-channel interference?
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hayyan

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how do you set power setting in cli? how do you check if station is connected to 5ghz or 2.4Ghz using command line?
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Nick Lowe, Official Rep

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Take a look at...

show cmds | include power

radio profile <string> scan access client power-save
radio profile <string> acsp max-tx-power <number>
interface <wifix> radio power <number>
interface <wifix> radio power auto
interface <wifix> radio power auto floor <number>
interface <wifix> radio power auto maxdrop <number>
interface <wifix> radio tx-power-control <number>
interface <wifix> radio tx-power-control auto
lldp max-power <number>
usbmodem power enable
usbmodem power cycle

show station will give you the channel information for stations.
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Peter Murray

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I would do a site survey and have a look at what the signal strength is in the facility on each band, not just at the locations where your users are having trouble but throughout rest of the facility. Even an informal site survey tool like Wifi Analyzer (for android phones and tablets) will give a good level of detail. Without knowing how large the area is that you're trying to cover, you may have APs interfering with each other (particularly on 2.4GHz).
As others have mentioned, you should check the documentation for the access points to verify how they should be oriented. They are not isotropic (omnidirectional in all planes) and thus may be radiating their power away from where you intend it to be. Again, the site survey would help indicate this, as reflections from metal ducts, boxes and other items may have unexpected results.