Intel 8260 support of 802.11k - issue

[BPlan]

----------- Still under investigation 28/11/2017 ---------

Hi,

I have been working on the implementation of 802.11k (along with 802.11v and 802.11r) in a Cisco wireless infrastructure. Our fleet is mainly Dell Latitude with intel wireless chipset 8260.

Running few tests and some packet captures, it seems that the Intel implementation of 802.11k is quite inefficient.

If the wireless clients do support 802.11k standard, trigger 802.11k reports from the WiFi infrastructure, it is done in a way that is inefficient and doesn't trigger a useful 802.11k report from the infrastructure.

The big gap missed out by the intel driver seems to reside in the 802.11k "neighbor report request" and the non specification of the SSID the client is on.

The consequence of this miss out is the WiFi Access Point replying an 802.11k "neighbor report response" of ANY nearby antennas on ANY SSID. Result being the very same Access Point (where the client is already on) sending a neighbor report of its other SSID (having the best signals). Hence making this feature (802.11k) completely useless.

A small improvement in the Intel driver (adding the specification of the SSID the neighbor report should report to) should make this 802.11k standard functional and add a big quality to the wireless driver.

I am happy to provide more details (packet captures...) or any help if required.

Infrastructure:

Dell Latitude using Intel Dual Band Wireless -AC 8260 (v19.50.0.11)

HP EliteBook using Intel Dual Band Wireless -AC 8260 (19.71.0.4)

Cisco Controller WLC 5500

Cisco Access Points 1142/3700/3800

[idata]

Hi Plantonb,

We are aware of your situation regarding the implementation of the 802.11k protocol on your Intel® Dual Band Wireless-AC 8260. We would like to let you know that this protocol https://www.intel.com/content/www/us/en/support/network-and-i-o/wireless-networking/000021562.html is supported by the adapter only on Windows(R) 10 using the latest drivers. It seems that the Dell* system is already using the latest drivers provided by the manufacturer but the HP* system is not.We advise you to try with the https://www.intel.com/content/www/us/en/support/topics/oems.html OEM latest drivers first. If the situation persists, we recommend you to perform a clean drivers installation and try with our generic drivers: 1. Download and save our latest Intel® PROSet/Wireless Software for Windows® 10: https://downloadcenter.intel.com/download/26924/Wireless-Intel-PROSet-Wireless-Software-and-Drivers-for-Windows-10?v=t Wireless_19.70.0_PROSet64_Win10.exe2. Under Programs and Features in the Control Panel, uninstall any instance of the "Intel® PROSet/Wireless Software." When prompted, choose to "discard settings."3. Go to the Device Manager > Network Adapters > Right click on your Intel(R) Dual Band Wireless-AC 8260 and uninstall it. Make sure to select the option to "Delete the driver software for this device."4. Clear out your temporary files: Press the Windows* Key + R to open the run box. Type Cleanmgr.exe and press OK. Here you will need to make sure Temporary Files are checked, you may uncheck everything else (unless you're ok with the extra wait) and press OK.5. Reboot your computer.6. Install the Intel® PROSet/Wireless Software that was downloaded back in step one.If the issue continues, please download and run our https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows- Intel® System Support Utility (while connected to your network) and share the resulting report with us. To enable file attachments, you will need to switch to the advanced editor mode while replying.We look forward to hearing back from you.Best regards,Junior M.

[BPlan]

Hi,

Thanks for the quick reply and the suggestions below. However it seems that the issue has not been fixed in the latest version of the driver or I haven't succeeded to explain clearly the situation.

As per your link regarding the supported protocols you have provided, 802.11k is supported yes-ish. Wireless clients advertise the 802.11k capability to the WiFi infrastructure but the Intel implementation of this protocol does not seem to allow this feature to work at least with Cisco infrastructure.

I have attached the system support utility report you have suggested me to run. I am indeed with Windows 10 and I have re-installed the latest Intel driver v19.70.0.5. The behavior is still the same.

I suspect the issue to come from 1 or 2 wrong fields in the Intel 's 802.11k Neighbor Report Request frame, generating a dysfunctional 802.11k response from the WiFi Access Point.

In order to be more explicit below are some packet captures pointing out the wrong requests from the Intel Wireless client:

Client's 802.11k Neighbor Report Request:

As you can see, 802.11k is implemented (client is requesting an 802.11k Neighbor report). However :

1 - Dialog token field value is "0" while this field is supposed to be a non-zero value (as per IEEE Std 802.11k) and used by the access point in the response to identify to which neighbor request this response is related to.

2 - In all the testings, the "Tag parameters" never include the SSID (Tag Number 0) however it does include various other Tag number (in that case Tag Number 29).

According to IEEE documentation, the Neighbor Report Request frame body should be as per follow

As a consequence, I would suspect the Access Points to never reply with a 802.11k "Neighbor report response" for the SSID the client is on.

And in the case of an access point broadcasting multiple SSID, the report generated will include a list of the other SSID which are on the same access point, making 802.11k completely inoperative (cause the client doesn't want to roam onto another SSID but onto another access point for the specified SSID).

As you can see as a Neighbor report response, the BSSID listed are for the very same access point (BSSID generated from the access point's MAC address + a last ID for every other SSID on the same antenna).

This behavior has been also explained and compared with other vendors such as Apple where we can see the SSID being included into the Neighbor report request here:

https://www.youtube.com/watch?v=XY3BentJmCA 802.11k Neighbor Report - YouTube - for a focus on Intel 8260 chipset jump at 17:39.

or here https://mrncciew.com/2014/09/11/cwsp-802-11k-ap-assisted-roaming/ https://mrncciew.com/2014/09/11/cwsp-802-11k-ap-assisted-roaming/ where we can also see the SSID being specified in the neighbor request.

Bottom line, it would seem to me that with a small fix with the driver, the intel wireless would take fully advantage of a growing standard that many organizations are interested in for their clients. Cause at the moment, the current implementation of Intel's 802.11k standard doesn't allow the clients to use this feature for roaming.

Thanks for your support.

Regards,

[idata]

Hi Plantonb,

Thanks for the information, we are going to investigate this matter and post a reply as soon as we have an update for you. Best regards,Junior M.

[idata]

Hi Plantonb,

Please check your private messages. Regards, Junior M.