Limit regarding number of connections?

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Limit regarding number of connections?

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Limit regarding number of connections?
Limit regarding number of connections?
2020-06-25 20:53:13
Model: EAP245  
Hardware Version: V3
Firmware Version:

Hello all,

 

I had a situation this evening with a training room... supplied with one EAP245 an 12 iPads... they all wanted to connect... which was not really possible. Is there a limit for the number of concurrent connections? About 8 of the iPads were able to connect to the 5Ghz channel... but the rest had problems all the time...

 

is there a limit or how can I avoid that in the future? 

 

Thanks and best regards,

 

Frank

 

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#1
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Re:Limit regarding number of connections?
2020-06-26 00:37:52 - last edited 2020-06-26 00:48:26

@FrankNeps,

 

there is definitly a limit of the internal data structures; in most APs it's 256 (only the manufacturer knows). As for EAP245 the recommended max. number of users is 80-100, depending on usage pattern. This recommended limit is just imposed by the amount of AirTime available to each client for sending/receiving data. If you exceed this limit, network performance will drop significantly.

 

Thus, 12 clients is no problem for an EAP.

 

But if you have band steering enabled in the EAP, further limits are imposed which cause an EAP to force clients to connect to the 2.4GHz band to balance the load between the two frequency bands. If this is the case you can try to turn band steering off.

 

In the past, iOS devices have been well known for WiFi connectivity problems with almost any AP when new iPad/iPhone models came out. Apple then fixes the firmware, so make sure you run latest iOS version on those iPads. I have several iPhones for testing which still have such problems; they often connect only after the second or third try.

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Re:Limit regarding number of connections?
2020-06-26 14:12:42 - last edited 2020-06-26 14:14:53

Hi @FrankNeps,

 

I concur with what R1D2 says.  I have two EAP225V3's in my home.  At any given time I have ~50 wireless devices spread between them, generally with 25-35 clients on one, and 15-25 on the other.

 

This consists of at least 11 Apple devices (iPads and phones, and a watch), 7 laptops, and multiple streaming and iOT devices (Nest Cameras, Rokus, light switches, etc.).  So there's is definately no issue with the hardware's capability to handle the traffic.

 

R1D2's suggestion of disabling band steering is a good one.  There are some configuration settings within the EAP regarding how many devices are allowed to connect to 5.8GHz vs 2.4GHz which can be set to limit how many devices are allowed to connect to 5.8GHz.  Also Band Steering itself can be buggy in the best of cases.

 

It sounds like you might not be the network admin.  I would talk with them an suggest the following:

 

1) Make sure iOS and your Apps are fully updated

 

2) Make sure the EAP45 firmware is fully updated

 

3) Make sure Omada  Server / OC-200 is fully updated

 

4) Disable Band Steering in Omada/on the EAP

 

5) Disable Air Time Fairness in Omada/on the EAP

 

6) Use separately names SSID's for 2.4GHz vs. 5.8GHz

 

7) Join wireless devices to ONLY ONE SSID at a time.  Either is fine, 5.8GHz is better / faster.  I generally have all of my 5.8GHz capable devices on 5.8GHz only -- including all of my Apple products -- Apple has supported 5.8GHz for a long time.  BUT, they also work just fine if connected to ONLY the 2.4GHz (I've tried).

 

8) I have seen on numerous occassions when band steering and/or the same SSID is used for both radios (2.4GHz & 5.8GHz) that Wifi devices get confused and constantly try to switch back and forth from one band to the other causing the "stuttering" and oscillating connections as you have described.

 

You said the EAP245 is in the same room with you, right?  So signal should be fine.  Transmit power should probably be set to Med or so depending on the site survey & layout.  Hopefully this EAP is hardwired (Ethernet connected) back to the switch and not MESH'ed -- I would assume so -- since it sounds like you're in a "commercial / business / academic" setting (vs residential) and MESH on the 245 is still in Beta.

 

One other thing to consider.  Not sure which Application you were using.  But if it is a Cloud based service or Video Conference type service (e.g. Zoom, Teams, Google Classroom, etc.) there's always a possibility that the application itself is havig issues.  Always good to run an internet speed test from each device to verify internet connectivity and speeds.  The check downdetector dot com to see if the application service is having any issues.

 

-Jonathan

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#3
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Re:Limit regarding number of connections?
2020-06-26 14:27:52

Thank you very much for your answer, I will try that next time... the iPads are updated with the latest iOS.

 

Due to time constraints I used the EAP245 right out of the box... which may have been too naive of me.

 

In the next step I will install the Omada software on a Linux server and maybe add a second EAP in the room.

 

Thank you for the advice with band steering. I will try that out.

 

It helps me a lot to know, that in general, the EAP245 should be able to handle that amount of connections.

 

Thanks a lot and best regards,

 

Frank

 

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#4
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Re:Limit regarding number of connections?
2020-06-26 14:33:59

Hi @FrankNeps,

 

Sounds good.  If you only have one (or even a few) EAP's you don't have to use Omada -- unless you really want fast roaming (regular roaming works fine for most).

 

But Omada is very nice and is worth the trouble if you plan to grow your deployment over time.  You can also buy the OC-200 Omada device, though it's hard to find it in stock recently.

 

-Jonathan

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#5
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Re:Limit regarding number of connections?
2020-06-26 14:43:04

Hello Jonathan,

 

thank you also to you. Very helpful... thanks for that many hints to configure the EAP245.

 

The iPads are up to date, but the EAP245 was used out of the box, I admit. That was a training with an application in the administration of a small city.

 

The EAP is hard wired connecting to a POE switch in the server room. I will also check the cabling there... but it should not be such a problem that the connection to the AP gets lost.

 

I will take the next steps with more time...

 

- update the EAP

- configure the EAP, the hints are really helpful, great!

- install Omada and maybe install a second EAP in the room. It is a big meeting room in the town hall. 

- maybe install a second AP in the room (thanks for the hint with the mesh)

 

Thank you so much for the many hints, I'm really glad and will try that!

 

Best regards, have a nice weekend and stay healthy!

 

Frank

 

 

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#6
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Re:Limit regarding number of connections?
2020-06-26 15:20:45 - last edited 2020-06-26 15:24:03

Hi @FrankNeps,

 

Sure, our pleasure.

 

Some other tips:

 

1) AP's should be ceiling mounted, facing down.  Preferrably mounted on the interior surface of the room (not sitting above the drop ceiling, for example).  Both should be separately hardwired back to the PoE switch

 

2) Make sure each of the EAP's radios are set to different, non-overlapping channels -- especially if you have multuple AP's in the same room

channels 1,6,or 11 for 2.4GHz 20MHz (do not use 40MHz) and channels 36 or 149 for 5.8GHz (if using 80MHz channels).  I would not use the 20/40/80 setting.  Use a discrete 5.8GHz BW -- you can start with 80MHz if you're only using two AP's in the room (assuming there is no other channel interference).  For super high density deployments you may need to limit this to 40MHz or even 20MHz if you have a lot of AP's in one location (so each can have its own channel).

 

3) You'll also want to turn down the AP transmit power.  Start with Medium -- e.g. 14-16 dBm on the custom scale and then adjust from there.  If you have two AP's in the room, you may need to go even lower.  Don't forget to change both radios (2.4 & 5.8 on each AP).

 

4) Most likely one, centrally located AP is fine, unless you are expecting more than 50+ clients.  But if the room is, for example, a basketball court, if using two AP's center one over each "half court".  Similar to this:

 

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What are the ceiling heights?  Normal 10 feet? -- if lower or higher this will effect the diameter of the RF cone, to some modest degree.

 

FYI, a lot of folks rush to get the 245 over the 225 because it has a 5.8GHz 3x3 radio.  But in reality, it's not clear that it really benefits most users.  Most folks don't really see any benefit to the 245.  It costs almost twice as much, has less frequent firmware updates, and most clients are only 2x2 anyway (soom 1x1).  Only the occasional super high end laptop has 3x3 Wifi.  In theory the 245 should support a few more simultaneous clients if MU-MIMO is working well.  But this newer Wave-2 functionality is still pretty buggy.

 

Of course use WPA2-PSK (or WPA2-Radius).  I generally leave the 2.4GHz radio set to "b/g/n" mode, and limit the 5.8GHz to "n/ac" mode.  b and g clients are still pretty common on 2.4GHz (unfortunately).  But "a" clients on 5.8GHz were always rare and these days are virtually non-existent.

 

Will you just have the "classroom" iPad devices on this Wifi network?  Or will there be additional SSID's setup for guests, personal devices, PC's, etc?

 

Have a great weekend,

Jonathan

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Re:Limit regarding number of connections?
2020-06-26 16:26:09

Wow, thank you, that's really very good to know! Again great help!

 

The AP is currently mounted on the wall... I'll change that... the ceiling in the big conference room starts at about 12 feet and goes up to at least 25 feet on the other side of the room. Normally (without Covid-19) there is room for the 18 councillors plus mayor plus some administration, press and some audience. There will be never more than ~25 or maximum 30 devices.

 

I could place the AP in the mid of the lower third of the ascending ceiling. This is no public and open AP, it's a closed network with WPA2-PSK, just for the purpose of the councillors meeting and their digital information system (that's the application which runs on the iPads). I asked the mayor... there is currently no plan to increase the network availability to guests or notebooks, just the between 20 and 22 iPads and two or three notebooks from the administration of the town to take notes or show presentations.

 

The advice with the channels is great and sounds good.

 

Thanks again and have a nice weekend, too!

 

Frank

 

 

 

 

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Re:Limit regarding number of connections?
2020-06-26 16:36:52

 

FrankNeps wrote

the ceiling in the big conference room starts at about 12 feet and goes up to at least 25 feet on the other side of the room. 

 

Don't mount it on the ceiling if higher than max. 24 feet, else the signal strength at the edges will become too weak.

 

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Re:Limit regarding number of connections?
2020-06-26 17:31:39

@FrankNeps,

 

In all likelihood, one AP is probably enough, even if only more or less centrally mounted over 1/3 of the area approx 12-15 feet up.  This would give a radius of about ~40 feet in all directions.  So unless the room is really long and skinny, you might not need the second AP.

 

-Jonathan 

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Re:Limit regarding number of connections?
2020-06-26 21:38:07

@JSchnee21 

 

The room is nearly a square, so that should not be a problem.

 

I'm not yet sure, how to test the new implementation, so that it works for the next training on July, 8th.

 

But I'll try to get as many devices as possible and get some help from my son ;-)

 

Thanks again and best regards,

 

Frank

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