Wireless troubles

[BjornAx]

Hello!

I wanted to ask for guidence here as i have an issue at my work with our WiFi.

Some of our users (Not all of them) have issues in certain conference rooms when having meetings over teams.

The problems they have is that during the meetings the call can freeze and you see the "Trying to reconnect Call" message in teams and then 20 seconds later it's all fine.

What the users have seen when this happens is that the WiFi icon in windows drop from 3 to 1 bar and then it go back up to 3 again and everything is alright for the rest of the meeting.

This however is not a windows specific thing as employees with Mac and Linux have reported the issues as well.

Unfortunately when i have tested this in the specific conference rooms everything has worked as it should.

The only thing i have noticed is that when the issues occur the machine is connected to a AP that is where the user was sitting before the meeting and the machine then roams to a nearby AP. Why this would cause a 20 second freeze in teams i do not know however.

I have tried to change the transmit power to see if the computers will roam earlier but doesn't seem to make a difference.

What i have tried:

Changed AP's from 6 year old devices to new CW9162I AP's

Slightly changing the location of the AP's to try and not make them overlap too much

Doing a netspot survey and it said everything was fine from what it could see

Changing the roaming aggressivenes setting on the Windows machines.

Disabling 2.4 GHz and only allowing 5&6 GHz

Changing radio transmit power to 14-17dBm for 5 GHz and 17-20dBm for 6GHz

Updated WiFi drivers on the Windows machines

Added traffic shaping for the teams services with the Expedited forwarding DSCP tag

Sorry for the long text but i am a bit out of ideas. We don't have a large office and use 6 AP's. We have our office in a new wooden based building so no concrete walls that block signals either.

We use MX95 as the main router and then MS225-24 for the switches

[rhbirkelund]

Go to Network-wide > Clients, and click on one of the clients that have been having issues. From there select the "Roaming" tab, and scroll to around the time that they had the issue. Do you see the client roam? Perhaps, when the users leave their workspace to go to a conference room and have a meeting, they may be "sticking" to their old AP before roaming to a new AP that may be better, from the conference room point of view. 

Bad roaming between APs may contribute to the clients roaming from AP to AP. If roaming isn't seamless there may be some issues with coverage or transmit power. In the ned, it's the client that determines when it is time to roam. 

[BjornAx]

Hello!

Thank you for the suggestion. I have looked at the roaming logs and during the time the user reported the issue i can see that the computer roams between 3 different AP's. But the roam time is at the maximum 100ms so i don't understand how that could cause a 20 second freeze in teams.

Or is teams that unoptimized so it can't handle a 100ms roam?

Yeah i know that it's up to the client when it wants to roam unfortunately. 😞

I might have to do some more troubleshooting with the transmit power. I think our coverage is optimal at least netspot thought so when i did the survey.

[rhbirkelund]

I also tend to QoS mark all packets on the Switch settings to "Trust Incoming", as I seem to recall that teams does some QoS marking aswell. So besides the QoS marking on the Access Points, but also on the switch in order to preserve the markings through out. You may also want to do so on the MX. But remember that once the packet leaves the MX for the Internet, all QoS markings are at the mercy of the Internet.