Assisted Roaming

802.11k Neighbor List and Assisted Roaming

The 802.11k standard allows an AP to inform 802.11k-capable clients of neighboring BSSIDs (APs in the same SSID). This can help the client to optimize its scanning and roaming behavior. Additionally, the Assisted Roaming Prediction Optimization feature can be used with non-802.11k clients, to discourage them from roaming to suboptimal APs.


Note
We recommend not configuring two SSIDs with the same name in the controller, which may cause roaming issues.

Prediction Based Roaming - Assisted Roaming for Non-802.11k Clients

You can optimize roaming for non-802.11k clients by generating a prediction neighbor list for each client without sending an 802.11k neighbor list request. When prediction based roaming enables a WLAN, after each successful client association/re-association, the same neighbor list optimization applies on the non-802.11k client to generate and store the neighbor list in the mobile station software data structure. Clients at different locations have different lists because the client probes are seen with different RSSI values by the different neighbors as the clients usually probe before any association or re-association. This list is created with the most updated probe data and predicts the next AP that the client is likely to roam to.

The wireless infrastructure discourages clients from roaming to those less desirable neighbors by denying association if the association request to an AP does not match the entries on the stored prediction neighbor list.

  • Denial count: Maximum number of times a client is refused association.

  • Prediction threshold: Minimum number of entries required in the prediction list for the assisted roaming feature to activate.

For more information, see https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/Enterprise-Mobility-8-5-Design-Guide/Enterprise_Mobility_8-5_Deployment_Guide/Chapter-11.html#pgfId-1140097.

Restrictions for Assisted Roaming

  • This feature is supported only on 802.11n capable indoor access points. For a single band configuration, a maximum of 6 neighbors are visible in a neighbor list. For dual band configuration, a maximum of 12 neighbors are visible.

  • You can configure assisted roaming only using the device CLI.

Configuring Assisted Roaming (GUI)

Assisted roaming allows clients to request neighbor reports containing information about known neighbor access points that are candidates for a service set transition.

Before you begin

Ensure that you have configured an AP Join Profile prior to configuring the primary and backup controllers.

Procedure

Step 1

Choose Configuration > Tags & Profiles > WLAN and click Add to add a WLAN or select an existing WLAN.

Step 2

On the Advanced tab, go to the Assisted Roaming (11K) and select the Prediction Optimization checkbox to optimize roaming for non 802.11k clients by generating a prediction neighbor list for each client without sending an 802.11k neighbor list request.

Step 3

Select the Neighbor List checkbox to optimize roaming for 802.11K clients by generating a neighbor list for each client without sending an 802.11k neighbor list request. By default, the neighbor list contains only neighbors in the same band with which the client is associated. However, if you select the Dual Band Neighbor List checkbox, it allows 802.11k to return neighbors in both bands.

Step 4

Click Apply to Device. .

Configuring Assisted Roaming (CLI)

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

wireless assisted-roaming floor-bias dBm

Example:

Device(config)# wireless assisted-roaming floor-bias 20

Configures neighbor floor label bias. The valid range is from 5 to 25 dBm, and the default value is 15 dBm.

Step 3

wlan wlan-id

Example:

Device(config)# wlan wlan1

Enters the WLAN configuration submode. The wlan-name is the profile name of the configured WLAN.

Step 4

assisted-roaming neighbor-list

Example:

Device(wlan)# assisted-roaming neighbor-list

Configures an 802.11k neighbor list for a WLAN. By default, assisted roaming is enabled on the neighbor list when you create a WLAN. The no form of the command disables assisted roaming neighbor list.

Step 5

assisted-roaming dual-list

Example:

Device(wlan)# assisted-roaming dual-list

Configures a dual-band 802.11k dual list for a WLAN. By default, assisted roaming is enabled on the dual list when you create a WLAN. The no form of the command disables assisted roaming dual list.

Step 6

assisted-roaming prediction

Example:

Device(wlan)# assisted-roaming prediction
Configures assisted roaming prediction list feature for a WLAN. By default, the assisted roaming prediction list is disabled.

Note

 

A warning message is displayed and load balancing is disabled for the WLAN if load balancing is already enabled for the WLAN.

Step 7

wireless assisted-roaming prediction-minimum count

Example:

Device# wireless assisted-roaming prediction-minimum
Configures the minimum number of predicted APs required for the prediction list feature to be activated. The default value is 3.

Note

 

If the number of the AP in the prediction assigned to the client is less than the number that you specify, the assisted roaming feature will not apply on this roam.

Step 8

wireless assisted-roaming denial-maximum count

Example:

Device# wireless assisted-roaming denial-maximum 8

Configures the maximum number of times a client can be denied association if the association request is sent to an AP does not match any AP on the prediction. The valid range is from 1 to 10, and the default value is 5.

Step 9

end

Example:

Device(config)# end

Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode.

Verifying Assisted Roaming

The following command can be used to verify assisted roaming configured on a WLAN:

Command Description
show wlan id wlan-id

Displays the WLAN parameters on the WLAN.

Configuration Examples for Assisted Roaming

This example shows how to configure the neighbor floor label bias:

Device# configure terminal
Device(config)# wireless assisted-roaming floor-bias 10
Device(config)# end
Device# show wlan id 23
This example shows how to disable neighbor list on a specific WLAN:

Device# configure terminal
Device(config)# wlan test1
Device(config (wlan)# no assisted-roaming neighbor-list
Device(config)(wlan)# end
Device# show wlan id 23
This example shows how to configure the prediction list on a specific WLAN:

Device# configure terminal
Device(config)# wlan test1
Device(config)(wlan)# assisted-roaming prediction
Device(config)(wlan)# end
Device# show wlan id 23
This example shows how to configure the prediction list based on assisted roaming prediction threshold and maximum denial count on a specific WLAN:

Device# configure terminal
Device(config)# wireless assisted-roaming prediction-minimum 4
Device(config)# wireless assisted-roaming denial-maximum 4
Device(config)(wlan)# end
Device# show wlan id 23