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Posts: 2
Registered: ‎05-22-2015

Determining if WLAN supports 802.11v

Is it possible to determine whether a WLAN supports BSS transition management (part of Wireless network management or 802.11v) from investigating Beacons sent by the AP?

 

Both Fast BSS transition(802.11r) and WLAN Radio Measurements (802.11k) support are contained within Beacon frames sent by the AP.  This advertises the support of these features to all potential clients.  However, I am not able to determine whether BSS transition management support is also contained within a Beacon frame.

 

A BSS Transition Request (sent within an Action Frame) can be sent autonomously or triggered by a
BSS Transition Query sent from a non-AP STA (client).  Refer to IEEE 802.11-2012, section 6.3.58.  The autonomous transmission of the request frame depends on the AP sending it.  However, the triggered event of sending the request depends on the client sending the query.  How does the client "know" that the AP suppports BSS Transition management?

Guru Elite
Posts: 20,981
Registered: ‎03-29-2007

Re: Determining if WLAN supports 802.11v

The client advertises this capability in the probe request.  Honestly, there is information about this on the internet, so I would just end up linking it here for you.

 



Colin Joseph
Aruba Customer Engineering

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New Contributor
Posts: 2
Registered: ‎05-22-2015

Re: Determining if WLAN supports 802.11v

Hi Colin,

  Thank you for your response.  However, I did not accept your response as a solution because the follow-up question would be: "Where in the Probe Response does advertisement of BSS Transition exist?"  After further investigating the IEEE standards (IEEE 802.11-2012), the following was determined:

 

1) section 10.23.6.1:
"Implementation of BSS Transition Management is optional for a WNM STA. A STA that implements BSS Transition Management has dot11MgmtOptionBSSTransitionImplemented set to true. When
dot11MgmtOptionBSSTransitionImplemented is true, dot11WirelessManagementImplemented shall be
true. A STA that has a value of true for dot11MgmtOptionBSSTransitionManagementActivated is defined
as a STA that supports BSS transition management. A STA for which dot11MgmtOptionBSSTransitionActivated is true shall set the BSS Transition field of the Extended Capabilities element to 1."

 

2) Table 8-103:
This table lists all the Capabilities field within the Extended Capabilities element (Element ID = 127)
Bit 19 = BSS Transition, The STA sets the BSS Transition field to 1 when dot11MgmtOptionBSSTransitionActivated is
true, and sets it to 0 otherwise.

 

And finally, the Extended Capabilities Information element exists in BOTH Probe Responses and Beacons.

3) Table 8-20
This table lists the Beacon frame body.
Order 41 = Extended Capabilities, The Extended Capabilities element is optionally present if any of
the fields in this element are nonzero.

4) Table 8-27
This table lists the Probe Response frame body.
Order 39 = Extended Capabilities, The Extended Capabilities element is optionally present if any of
the fields in this element are nonzero.

 

Also attached is a screenshot of the Exteneded Capabilities field.  In this case, the AP does not support BSS Transition.

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