CTS 234: 802.11k and 802.11v

From Clear To Send: Wireless Network Engineering Rowell Dionicio and François Vergès

We’re taking a look at a high level look at 802.11k and 802.11v. How have we seen it in the environments we go into today and do the devices support 802.11k and 802.11v?

First, determine if the Wi-Fi infrastructure has 802.11k/v enabled. This is fairly easy to determine and François has a great blog post about it.

Then the challenge may be identifying if the client supports 802.11k/v.

The most notable purpose of 802.11k is to provide Neighbor Reports to the client. This report contains a list of neighboring access points in which the client can roam to. This allows the roam to be efficient for the client, avoiding the process of scanning for access points on different channels. It saves time. In the standard, you can find 802.11k under Radio Measurement. Check section 4.3.11 inside the 802.11-2016 standard.

802.11v contains a lot of capabilities. Under the 802.11-2016 standard you can find it under Wireless Network Management, section 4.3.18. You may have heard of BSS Transition management. This is the process of telling a client about moving to another BSS.

Where we tried to test out 802.11v is with Cisco’s Macro/Micro cell. With a dual 5 GHz configuration, Cisco will leverage 802.11r/k/v to move a client in and out of the cell.

We plan to dive in deeper into the 802.11-2016 standard for another episode. We wanted to keep it a little light this time around.

If you want to check it out for yourself, get some frame captures and apply a filter for these frames.

802.11k

Management Action Frame, Category: Radio Measurement:

wlan.addr == xx:xx:xx:xx:xx:xx && wlan.fc.type == 0 && wlan.fixed.category_code == 5

802.11v

Management Action Frame (Category: WNM):

wlan.fc.type == 0 && wlan.fc.type_subtype == 0x000e && wlan.fixed.category_code == 10

BSS Transition management query:

wlan.fc.type == 0 && wlan.fc.type_subtype == 0x000e && wlan.fixed.category_code == 10 && wlan.fixed.action_code == 6

BSS Transition management request:

wlan.fc.type == 0 && wlan.fc.type_subtype == 0x000e && wlan.fixed.category_code == 10 && wlan.fixed.action_code == 7

BSS Transition Management response:

wlan.fc.type == 0 && wlan.fc.type_subtype == 0x000e && wlan.fixed.category_code == 10 && wlan.fixed.action_code == 8

802.11k Neighbor Report Request

802.11k Neighbor Report Response

What is your experience with 802.11k/v?