How to troubleshoot Spectrum load balancing in Aruba Instant? What are the commands and important fields?

Aruba Employee
Aruba Employee

This article helps us to troubleshoot Spectrum Load Balancing (SLB) issues by introducing us to the commands along with their different fields and flags.


  •  ARM (Adaptive Radio Management) must be enabled for the Spectrum Load Balancing to function
  •  Lower values for "SLB Neighbor Matching" and "SLB Threshold" triggers SLB easily and effectively.
  • SLB feature is in action only when a client first connects onto the network. There is no dynamic load-balancing once the client is already associated to an AP.

Environment : This article applies to all Aruba Instant Access Points running Aruba InstantOS or higher.



By default Spectrum Load Balancing is enabled on IAP. However, follow below steps to enable:

From GUI:


  1. Login to web interface of IAP 
  2. In the top-right menu, clicn on "RF"
  3. From the dropdown, select "Enabled" for Spectrum Load Balancing
  4. For further configuration parameters related to SLB, click on "Show Advance Options"
  5. Here, SLB calculating intervalSLB neighbor matching % and SLB Threshold can be configured.
  6. Once finish, click OK.

Below is the screenshot from GUI:




SLB calculating interval can be verified from ARM configuration of an Instant AP. Below screenshots shows how to verify from GUI and CLI:

From GUI:


  1. Login to web interface of IAP 
  2. In the top-right menu, Point to "More"
  3. From the dropdown, select "Support"
  4. From the "Command" dropdown, select "AP ARM Configuration"
  5. The "Target" dropdown, shows the list of Instant AP's in the cluster and thereby one can select the AP that the command has to run. Here, select the access point that has "(VC)" beside it. This Instant AP is the Virtial Controller for the cluster.
  6. Click on "Run" button.

Below is the reference output:



From CLI:

SSH or Console, into Virtual Controller and execute the below command:

# Show arm config


rtaImage (1).jpg


Below are the commands that would helps to understand the statistics of SLB:

# show ap debug spectrum-load-balancing x

(Where, x stands for radio: 0 or 1.  0 is for 5.GHz and 1 is for 2.4GHz)

This command is radio specific and shows if the SLB is enabled and active on a particular radio. IAP's send updates (such as client propagation information)  in the form of Information Element (IE) into probe request packets. This update is checked across its own density map to decide if the AP falls with same RF neighborhood or not.

IAP# show ap debug spectrum-load-balancing 0



Spectrum Load Balancing Status: RUNNING, Associated:1, Threshold:5   ===> Client Count Threshold




Spectrum Load Balancing Neighbor Table




MAC                     Channel   Client_Count   Flags        Recved_Seconds


---                             -------     ------------      -----          --------------


00:24:6c:07:b2:60  48             0                     VR               85


00:24:6c:24:24:50  165           3                     VR               136


00:24:6c:33:06:00  165           9                     V                  281


00:24:6c:24:17:60  161           0                                         2180


00:24:6c:07:7e:80  36             0                     S                  296




Neighbor Flags: V - Valid; R - Is in Virtual RF Neighborhood; S - Same Channel


  • AP's with "VR" flag, are valid and in the same RF Neighborhood domain.
  • Whereas, AP's with "V" flag are valid but not in the same RF domain as the Instant AP that we are running the command on.
  • APs with "S" flag, indicates that they are on the same channel.
  • "Recved_Seconds" is the amount of the seconds before the update was received from neighbor AP of same RF neighborhood.


Note: The entry in the SLB neighbor table is aged out, if no entry from the neighbor AP is received in 5 mins (or) 300 seconds.
Even though SLB is enabled, Load Enforcement is activated only when below condition is matched:


Current_associated >= Client_Threshold

Within 5 seconds after Load Enforcement is activated, the AP would Ignore probe requests, Sends Auth failures, and Sends Association failures.

Below command show SLB statistics on a radio of an AP.

# show ap debug radio-stats x | include SLB

 (Where, x stands for radio: 0 or 1.  0 is for 5.GHz and 1 is for 2.4GHz)


For radio 0:
rtaImage (2).jpg
For radio 1:
rtaImage (3).jpg
"SLB: Probe Requests Sent" is an important parameter here. In SLB, IAPs keep other IAPs updated using Probe request frames and Probe response frames. In these frames, they include a IE (Information Element)which contains  density map, working channel, and current associated clients count in that radio (sum of all vaps).





Version history
Revision #:
1 of 1
Last update:
‎07-03-2014 06:52 PM
Updated by:
Labels (1)
Search Airheads
Showing results for 
Search instead for 
Did you mean: