Issue consistently connecting Vaisala HMT140 Data Logger to C9800 WLAN

[connellj]

We have a Medical Manufacturing customer, and they have 10 Vaisala HMT140 WiFi Data Loggers (collect temp and humidity measurements).  These devices connect approximately every 30 minutes and sends it data to a collector.  These devices were previously connected to a WLAN managed by a Cisco 8510 using WPA2 with a PSK.  We have migrated the network to the C9800 environment using 9115 access points and the SSID is configured using WPA2 with a PSK.  On the previous network, there were no issues with  the devices connecting every 30 minutes, when we moved them over to the new Wireless network, several are having issues connecting consistently (fortunately they can store about half a days data and send it and we are seeing a connection at least every 2 to 3 hours, worst case scenario).  We have verified the signal strength at the locations of the end devices, and they are all good.

I have reached out to the manufacturer to see if they have any suggestions and are waiting for a reply, but thought I would try here as well.

[Arshad Safrulla]

Which IOS-XE code are you running? Is the device 5GHz capable? There are instances I have seen IOT devices which comes with AC chipset doesn't play well with new AX AP's due to chipset and driver issues. My plan would be as below

1. Disable all AX features and test again (I know WiFi6 has TWT, but still you need TWT capable clients)

2. Register an AC AP with 9800 and try connecting the client.

3. Test with different IOS-XE codes, preferably 17.3.3 or 17.3.4

4. OTA capture for advance tshoot (may be you can do this first)

5. Try to profile the client with 9115 AP to see how it behaves when different channel width's used, different channels, different TPC levels etc.

[Leo Laohoo]

I have seen this sort of behavriour before and it brings back horrifying memories.  

It was an Ekahau-branded RFID tags (first gen).  What is written in the data sheet and what is written in the "disclaimer" portion of the configuration guide are two different things.  Because we have disabled data rates from 1- to 11 Mbps, the tags require 1 Mbps to be able to join the SSID.  Only after joining SSID willl the tags go up to 12 Mbps but 1 Mbps is required -- And this vital information was removed from the Datasheet.  

Create an SSID with all settings "dumb down" and an OPEN SSID.  If it works, start ramping up the settings until something breaks.

What firmware is the WLC running on?

[connellj]

Hey Leo - thanks for the idea.
We are running 17.3.2a, just waiting on the new 17.x revision to come out to upgrade. I did create a SSID that was wide open, but did not think about the speed, I will try that. I am still not 100% sure that it is a WLAN issue. They have 10 of the devices and six connect consistently, one connects about 75% of the time, and the other three connect about 60% of the time. They only connect about every thirty minutes, dump their data and then disconnect. The ones that are having an issue connecting, I see their history in Prime and it is showing that they authenticated, I am just not getting an IP address, like I do when they work properly (the IPs are statically configured, so it is not a DHCP issue).

[Leo Laohoo]

17.3.4 was released a few weeks ago.  Think about it.

[connellj]

If it was up to me, we would at least be on 17.3.3, but when I went to do the upgrade, our global certification team told us that we would be upgrading to 17.6 shortly as they were testing and certifying it, then the major security issue came out and they paused it, and we would be waiting for 17.6.1 to be released. To upgrade the code takes a lot of approvals, we have over 300 sites and nearly 3k (and growing) access points connected, some are manufacturing and warehouse environments which run 24x7.
17.6.1 was released the end of July, so they are finishing the final certification and I am hoping to be able to do the upgrade to the main pair mid-October (after the year-end change freeze), and the ones that are at individual sites by mid-September (before our change freeze).

[Leo Laohoo]

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@connellj wrote:
our global certification team told us that we would be upgrading to 17.6 shortly as they were testing and certifying it

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Reading this line made me expel my coffee onto my screen.  

17.6.1 was released 31 July 2021.  It will take about 18 to 24 months before 17.6.4 comes out.  

One of the major benefits to the 9800 (against AireOS) is firmware upgrade.  The WLC firmware can be upgraded and the APs do not need to be upgraded (and no reboot).  And if the AP needs to be upgraded the WLC can "prioritize" and select which APs have zero clients and do those first.