Hello,

I have been a Mikrotik user for more than 5 years now. I just have one of the most disappointing and frustrating experience that I want to share. This is a very strange incident and maybe you can share your thoughts on possible things that caused this in our event.

I have deployed a wireless network in a theater for a one day event. My backbone setup it this:
1. 3 ISP (total of 175Mbps) -----> connected to 3 ether ports of my CCR (CCR1036-12G-4S). (located in a data center)
2. CCR to the 3 IDF over fiber backbone of the building (using the 3 SFP ports on CCR)
3. on the IDFs - fiber to SFP is connected to RB 260GSP
4. RB 260GSP to a CRS (CRS210-8G-2S+IN) ------ theater location
5. CRS is connected to an HP Layer 3 switch
6. HP switch to 5 GrooveA 52HPn and others & 4 GrooveA 52HPn connected to the CRS

The setup of the Grooves and other APs are very basic, they are on home ap setup. Ether has as a static ip from the /16 network of the CCR and wifi is serving its own dhcp with a /22 network. Connection is routed to the CCR.

Wireless setup - 2.4Ghz, 20MHz, on separate channels, transmit power lowered to 8-10dBm. Each has its own SSID with their corresponding passwords...

When I'm on cable (connected to the CRS) - I can get a a full 175Mbps download. So I know that the connection from the data center to the theater area is rock solid. Have tested is for more than 3 days.

When all WiFi are setup, we tested each AP continuously and we consistently get a download speed of 20-30Mbps.

Now the event day. Minutes before the start of the event, we conducted the tests, and all APs have alteast 9Mbps of download speed. Our devices - laptop and mobile devices can easily connect to every AP. But when the event started, we noticed that majority of our users can't seem to find some APs' SSID, and those who can see the SSID are having a difficult time to connect. One MacBook pro of a presenter was having a hard time as well connecting even if the AP is just 2 meters away from the device, and when the device was able to connect, it can ping, it can resolve DNS, but wasn't able to browse on safari on all websites!

2 of my engineers are roaming the theater during the event, and they can't seem to connect to ALL of our APs. We tried to adjust transmit power to high, highest, low, lowest, we even tried to turn off all radios but 4 but still can't connect.

We really don't have any idea what happened.

The event on the theater was around 1PM to 530PM. Half-way through the event, I can see a few devices that are connected, but seem to get disconnected after a few minutes of connection. Then I tried to open my wifi analyzer in my android device. When I checked on the time graph (ssid strength over time) I saw this:
I was shocked to see that ALL wifi ssid seemed to stops in various intervals. Even SSIDs of radios that aren't ours! And from the graphs, it seemed to stop for a couple of seconds...

Then around 6PM, when the event was about to finish, I suddenly saw that one of our engineers who roamed the theater got a successful connection and a good download speed. Then I checked my analyzer again and saw a different behavior on the wifi time graph:
I observed for more than 2 hours and still see the same behavior. No SSID is stopping and all devices can easily connect and can get a good download speed.

Also, just want to inform you that we also have 4 huawei AP6010 series and 4 Altai C1n, all have the same issue as the other Mikrotik APs.

Any thoughts please?

Gotta be interference. I am no expert, and wireless fails me many times, but what changed? The amount of clients.

I am regularly in a few places that have 90+ different access points / ssids in a few hundred meters. The noise that is generated is immense. A concentrated place like a theatre, with 1000 clients is bound to be noisy. I can tell because at some points you are saying the radios lost all connections to anything. Was it really radio silent? I doubt it.

Maybe you had too many access points (9) for such a small place? maybe there was a power mismatch with AP's overwhelming clients or vice versa? Like i said im no expert, but it sounds like interference from too much signal to me.

At work we use cisco wlan controllers to manage the aps and make sure they are not conflicting with one another. Not sure if that's necessary for a temp event, just additional information.

If the grooves had omni antennas they could interfere with each other. You should rather think about sectors with high attenuation on the sides when covering large open space.

Results are pretty typical, regardless of vendor. This requires a decent amount of engineering and a managed wireless network - not just plug a bunch in and cross your fingers.

You can't even remotely "test" this without having the expected number of client devices present, either.

The fact that you started throwing power levels all over (and my god, on highest?! You want loooooow power here) shows you weren't prepared for this.


Sent from my mobile device.

Hi,

Did you check the logs of the AP's to see if there is some kind of error?

Also my guess is the max station count, usually is defaults to 2007 stations but I have seen some cases where it defaults to about 32.

Was all the AP's country set correctly?

Your issue was most probably caused by interference between the AP's