topic Re: Problem with MAC's moving around in School in Aerohive Migrated Content

Problem with MAC's moving around in School

jan_boje — Mon, 07 Jan 2019 23:03:49 GMT

We have about 4000 student using a Macbook Pro, Macbook Air. About 10% of those have problem when they change classroom. the Mac's is still connecting to the classroom they come from.

We have set "radio and rates" on 5.0 GHz to basic 24Mbps and up.

Our solution is to disable wireless og the client and on again.

Can we do anything to impove this in our configuration, radio profiles or ??

Our accesspoint is AP250 and AP370 with Hivemanager Classic.

Jan Boje

Re: Problem with MAC's moving around in School

samantha_lynn — Mon, 07 Jan 2019 23:20:23 GMT

Another way to influence stronger connections between the AP and client device, to encourage a client to connect to an AP that is closer to them, would be to adjust the Weak SNR Probe response. This is done in the Radio Profile, under the Optimizing Management Traffic Settings section.

You would want to check the box next to "Selectively respond to probe requests if the SNR is stronger than the weak SNR threshold", then adjust the Weak SNR threshold. An SNR of 10 dB or lower is generally considered poor and an SNR of 25 dB or greater is generally considered good, with the default being 15 dB.

I would be very careful when adjusting this setting. If you adjust too far in either direction, you would block healthy connections. I would adjust by 1 or 2 dB per test, so for the first test maybe go up only as far as 17. This will encourage APs to respond to clients with strong signals, so the clients should be passed to an AP that is closer by the client when they move locations.

Re: Problem with MAC's moving around in School

jan_boje — Tue, 08 Jan 2019 01:35:11 GMT

Thanks for the answer.

our SNR is set to 25dB, is that to much

Re: Problem with MAC's moving around in School

samantha_lynn — Tue, 08 Jan 2019 01:39:37 GMT

That's higher than I would have recommended going to all at once, but if you've already been there and your connections aren't failing then you should be fine with 25, and if you wanted to try 27 that shouldn't be too drastic a shift to block healthy connections all at once. If you've noticed that sometimes you have trouble connecting and have to try a couple times, I wouldn't recommend going any higher than where you are now.

Re: Problem with MAC's moving around in School

jan_boje — Tue, 08 Jan 2019 02:30:30 GMT

I Think I will try to go down to 23 dB, we do have some client where connecting time is to high.

Nothing else to try ?

Re: Problem with MAC's moving around in School

samantha_lynn — Tue, 08 Jan 2019 04:53:55 GMT

What is the broadcast power in use? We could actually answer a lot of questions at once if you can send me tech data from an AP with a client still connected when it should be connected to a physically closer AP. If we can't get that, tech data from any AP will still let me see what we're working with now. If you'd like to email that directly to me, my email is communityhelp@aerohive.com.

To get tech data you'll want to go to Monitor> Select the check box next to the AP> Utilities> Get Tech Data.

Re: Problem with MAC's moving around in School

samantha_lynn — Tue, 08 Jan 2019 21:38:34 GMT

Thank you for that data. I see we are using the max power setting on the 5GHz radio, could we try lowering that to see if that helps the clients roam when needed? The max power level is 20, the lowest is 1. I usually also recommend adjusting this by 2dBm per test, so we don't cause drastic shifts in the signal coverage area all at once.

Re: Problem with MAC's moving around in School

jan_boje — Tue, 08 Jan 2019 21:51:29 GMT

hej Sam

I will change this in the radio Profile "Max Transmit Power (10-20 dBm)" from 20dBm to 18 dBm. School is closing now, anything else we should try ?

otherwise I will be back around this time Wednesday.

Re: Problem with MAC's moving around in School

AnonymousM — Tue, 08 Jan 2019 22:56:37 GMT

Jan,

See https://support.apple.com/en-us/HT206207 for specifications on how Mac OSX devices roam. Ideally, your WLAN should be configured/tuned to meet these specs to improve this.

As Sam said, if your output power is high and the devices are not meeting the threshold required for them to start probing out to find a new AP to roam to, they could stick to their currently associated AP. And with a 24 Mbps data rate configured, there could be client related issues as they may not be able to maintain a link @ 24 Mbps (FWIW, Apple recommends not going above 12 Mbps as the minimum data rate). It's a Cisco doc, but still provides some relevance - https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/technotes/8-6/Enterprise_Best_Practices_for_iOS_devices_and_Mac_computers_on_Cisco_Wireless_LAN.pdf

Re: Problem with MAC's moving around in School

jan_boje — Tue, 08 Jan 2019 23:24:24 GMT

I have been reading the conclusion, should I try to go down 12 Mbps as the min. datarate ??

by the way it would be nice if Aerohive made the same whitepaper as Cisco 🙂

Re: Problem with MAC's moving around in School

AnonymousM — Wed, 09 Jan 2019 00:06:02 GMT

I can't really answer that as I know very little about your WLAN environment. As changing the base data rate also impacts Beacon frames and other management frames. Since 12 Mbps can be decoded at a further distance than 24 Mbps, clients may be even more sticky.

What channel width are you using? What specific radio profile configurations? There are some good docs from Aerohive on configuring things for high density in education here - http://docs.aerohive.com/330000/docs/help/english/ng/Content/reference/docs/deployment-guides.htm

If it were me, I'd look at cleaning up configuration. Find a way to make your WLAN fall in line as best it can with the links attached here and prior.

The other route is to hire a 3rd party to come and assist and clean up things. Aerohive themselves also sells professional services for this sort of thing.

Re: Problem with MAC's moving around in School

jan_boje — Wed, 09 Jan 2019 04:04:39 GMT

We have used the "best practice guide" from Aerohive. We have had an expert here in Denmark to look at the radioprofile and so on. He had make a good job - no problem. But still we got problem with Mac computers.

When I read the paper from Cisco. I would really like if Aerohive, would do the same. What is best practice for Mac computere. To day we have one SSID and radius to split the student. When I read the Cisco paper, and they are suggesting to SSID one for PC and for MAC. Is that a good idea Sam. I d'ont know.

Re: Problem with MAC's moving around in School

samantha_lynn — Thu, 17 Jan 2019 03:31:05 GMT

I've been asking around to see if we have any similar documentation but I haven't been able to find anything. In general, I can't see how a separate SSID for PC and MAC would help.

Re: Problem with MAC's moving around in School

jan_boje — Thu, 17 Jan 2019 04:05:11 GMT

thanks for trying. when reading the Cisco paper, i would say that there is some difference. We have set "max transmit limit" to 18. Asking around the student if it got better, but the answer… meaby 

I have to find a student which have problem with the Mac and roaming. I have seen reconnect on a mac in 6 sek (wireless off and then on again) and up to 90 sek for another mac.

Re: Problem with MAC's moving around in School

AnonymousM — Thu, 17 Jan 2019 04:50:10 GMT

Jan,

What does your AP deployment look like? Able to share a map that shows AP locations? Do you see 8-12 dB difference between APs in classrooms? As that's one of the criteria for an OS X device to roam outside of it crossing the ~-70 dBm threshold for RSSI for the currently associated BSSID.

Re: Problem with MAC's moving around in School

jan_boje — Thu, 17 Jan 2019 05:06:39 GMT

Hi Brian

I am very busy this week, so I will be back next week with a map. Is there an easy way to see the "dB" difference between AP's in classroom.

Re: Problem with MAC's moving around in School

AnonymousM — Thu, 17 Jan 2019 05:08:55 GMT

An analyze software would show this. Adrians Wifi Explorer shows it - https://www.adriangranados.com but it's not a free product. If you have an iPhone, you can download Apples Airport Utility - AirPort Utility on the App Store - iTunes - Applehttps://itunes.apple.com/us/app/airport-utility/id427276530?mt=8 - and enable it to do passive scans of WLANs and see how the iPhone sees the differences.

Re: Problem with MAC's moving around in School

jan_boje — Thu, 24 Jan 2019 20:23:00 GMT

Hi Brian

I have been into tree classroom and I have taken a screenshot of the wirelees activity.

As you can see, the accesspoint in the classroom is the "strongest" one.

The student is not complaining, when they are connected to the wireless. They are complaining over the time it takes to connect/reconnect, we are talking up to 120 sek.

The problem exist when they start in the morning and when they move to a new Classroom.