I work at a school district that has about 1000 students that is split into two buildings. In our junior high/high school building, we have about 300 student laptops with about 25 teachers that each have a laptop and most also have a desktop with a wireless connection.
Our elementary building has about 200 student laptops and another 20 teacher laptops.
Here is our problem. All year we have had a seemingly sporadically slow network. At certain periods of the day, things become very bogged down, people begin losing their connections often…it's a nightmare.
We started with a Ubiquiti Unifi wireless system with full building coverage in both buildings and netgear GS748TPS, 748TP, and 724TPS switches. The entire wireless system is built on a cat 6 infrastructure.
If a teacher laptop is connected to an access point, everything is fine. When a jr high or high school student connects to an access point and tries to do anything over the network (pulling files from the file server, udp desktop monitoring traffic) except for http access, ping times for everybody on that access point, including teachers, skyrockets into the thousands.
In the elementary building, there is not a single problem with any connections or ping times. If I ping from the high school to a laptop in the elementary school 8 miles away, I get an average of 1ms ping times.
We have tried removing any software that could create an issue, we have tried removing all startup programs, we have replaced access points to see if it was a bad access point, we have replaced the POE adapters, we have replaced the ends on the cable runs, we have tried reverting everything from the netgear switches to our old HP Procurve 2810-48g switches and removing the netgears entirely, we have tried removing the Unifi access points and putting our HP Procurve wireless system back into production, we have tried any version of the wireless driver driver for that particular laptop that we can find.
None of these issues happened at all last year, but it has been non stop this year and it is severely detrimental to any classroom activities. We also have standardized testing coming up.
I am pretty much at a loss as to what else could possibly be causing the problem and am very open to any and all suggestions and recommendations. Please let me know if there are any resources that would help out.
Best Answer
The actual solution is to change a few settings of the wireless NIC in windows.
Three things needed to be changed in the card's settings in order to fix this.
1) Change the 802.11n channel width from the default (20) to auto
2) Turn off bluetooth in the card's properties
3) Set the Roaming aggressiveness to High
Immediately after, we were getting 100 Mbps downloads over the LAN when we were previously getting 500 Kbps.
The originally accepted solution below is no longer valid. Unifi products are not, in fact, the cause of the issue.
After extensive testing and multiple situations, it appears that the Intel Centrino 2230 Wireless NIC is simply incompatible with Ubiquiti Unifi access points.
Replacing the NIC with a 1x1 WLAN NIC from previous machines completely alleviated the problem. Connecting to the access points of three other brands worked fine as well.
We attempted to connect them to a Unifi AC access point, as well. Nothing changed.
Neither updating nor backdating drivers on the chipset and WLAN didn't work.
It appears to just be totally incompatible between the Centrino 2230 WLAN NIC and Ubiquiti Unifi access points.