Trying to improve fast roaming

[MarkS]

Hi,

I'm new to the WiNG software so still getting to grips with the interface and features. I'm no WiFi Expert but can normally find my way around.

In my new role I have inherited 3 x NX-5500 (v5.8.0) controllers and about 100 AP's (AP650 & AP7522).

One of the WLANs (WPA2 with Passkey) is used in the warehouse where the terminals (FLT Mounted & MC Handheld Guns) are roaming around the warehouse. There were previously WAY too many AP's in the warehouse but this has been reduced now and we have used heatmapping software to check the signal strength around the warehouse. Also the channels in use have been staggered.to reduce any overlap, but SmartRF is not enabled.

The application on the devices constantly talks back to the server updating pick & Pack instructions.

We notice on the handhelds, if running a constant ping, that they occasionally lose single pings as we walk through the warehouse. I am assuming this is as they switch to a different AP.

However on the FLT mounted units, as they fly at breakneck speed through the warehouse, the drop out is much more pronounced and because it drops for so long, the software times out.

If we change the network settings and disable WPA, reducing to an Open network locked down to a MAC based ACL, then the drop out is less pronounced and the software is able to recover the dropouts.

Summary, it seems that when encryption is enabled and the FLT units roam quickly around the warehouse the problem is worse. With Encryption disabled, the problem is slightly better.

Q1: Is there any general performance benefit to setting the WLAN to work in Tunnel mode rather than local (currently Tunnel)?
Q2: Is there any roaming benefit to using Tunnel based mode over Local?
Q3: I understand the negotiation with Encryption enabled takes longer but I assumed we were talking in the milliseconds, so why would the roaming take so much longer on the devices that are travelling faster?
Q4: If Roaming assistance is applied in the configuration, is this likely to help the issue or am I likely to still get the dropouts as the unit switches between AP's.

Apparently my employer has previously had a Motorola/Zebra engineer out to look at this and they never got to the bottom of it. Either, this problem has flummoxed the experts or the expert was a bit **** at his job.

Thanks in advance for any help

[MarkS]

Hi Andrew,

Thanks for your reply.

I'm not sure what software was used for all of the mapping and surveying, different consultants were used and it's all before my time with the company.
One of my predecessors produced a heat map using Ekahua. I've never done heatmaps before so I'm just looking around for something to use.

Initially one company came in and suggested way too many AP's. These were installed and they had issues.
Another consultant came and said there were way too many APs and a good 60-70% were removed.
There is now one every other aisle, in alternating aisles. Channels have been configured to to try and put the greater distance between other AP's on the same channel.
Also, 5Ghz band has been disabled

I'm not too sure what fast roaming options are available as I've never needed to specifically configure anything for fast roaming before, so I'm about 48 into investigating this problem and learning as I go.
I believe there was a BSS Fast Transition option but I may need a firmware update to get the feature.

Mark