Android App issues with WiFi infrastructures

[Nexacom]

Hi Everyone,
We have about 40 offices of the same client equipped with a hosted 3cx. with, on each site:
- 3cx SBC + a few IP phones, working absolutely perfectly
- 10 to 20 Android apps on Samsung A20 and Samsung J6 smartphones
- SDSL line dedicated to VoIP, 20% use of bandwidth
- A Ruckus wifi infrastructure. Every base is wired, the wifi works perfectly for data on smartphones. Several offices are equipped with Juniper WiFi infrastructure, the problem is the same. the The smartphones have no sim card, just wifi use.

And it is not reliable at all: phones wake up correctly when incoming calls, but very often, the voice quality is poor, blanks, etc, even if we are just under a wifi base with perfect signal and no packet loss, low latency.... we spent two years troubleshooting with 3cx support, wifi support, we can't find the solution. Eveything has been tested (fine tuning of the smartphone, codecs, firmware updates, app updates...)
However, absolutely NO PROBLEM with Iphone with no sim card.

Ma question is: is it possible that the problem comes from the ability of the smartphone to switch from one base to another, or to connect to the best base itself? Does anyone encounter the same issue?

Thanks a lot

 

[NickD_3CX]

Hi!

First I want to say that it so happens that we also have a Ruckus infrastructure with multiple APs all over the building, but I have not experienced this same issue, neither while standing still, neither when walking around where inevitably my phone must have handed off to another AP.

is it possible that the problem comes from the ability of the smartphone to switch from one base to another, or to connect to the best base itself?

As far as I have read, the mobile phone also needs to correctly handle the hand-off between bases and there are many 802.11 standards concerning hand-off and AP selection.
Is there some reason you suspect this? If you are standing still in an area of an office where only 1 AP covers, do you still have the same problem?
Also I see that your devices are both Samsung. Would you happen to have some newer phone from another manufacturer, just to try as a test?

 

[Nexacom]

Hi,
Thank you for your answer. Is your AP controller on-site, or in the Cloud?
There is a MDM for the smartphones, but I don't think that could occur problems.

Well, Galaxy J6/A20 are entry level smartphones, so maybe the wifi chipset is "cheap"; so their ability to roam between APs is bad... Otherwise, why is it working correctly with an Iphone?

With just one AP (tested in my office) it works properly.
I'm going to test with a OnePlus Nord100 (same range of products) and a Pixel 4A (middle range), to see if the result is better.

But if someone has encountered the same kind of problem, let me know. I give you the tests result as soon as I can.

 

[NickD_3CX]

Thank you for your answer. Is your AP controller on-site, or in the Cloud?

I didn't assist in the our setup so please excuse me, but from what I know, we have an on-prem Zone Director and all APs are set to direct the traffic to the director, which in turn outputs the traffic from all APs to a single switch port.
I think this is done by enabling "Tunnel Mode".

This prevents the ARP "mess" of all APs sending traffic directly to the network.

This I assume helps not-so-capable phones to not mess up the RTP traffic.

[EDIT]
I actually found a post from some time ago explaining how we set it up:
https://www.3cx.com/blog/voip-howto/ruckus-wireless-infrastructure/