Environment : This article applies to all Aruba Instant Access Points running Aruba InstantOS 6.2.1.0-3.3.0.0 or higher.
Balancing spectrum utilization rather than number of clients per AP reduces co-channel interference and increases performance. Hence spectrum load balancing is based on the concept of creating virtual RF neighborhoods among access points for efficient client association management.
Spectrum Load Balancing (SLB) divides APs in a cluster into several logical virtual RF neighborhood domains and these AP's in the same RF neighborhood share the same clients. For example, in the below figure, there are 15 Instant APs in a cluster. Take AP1, AP2 and AP3, each of them has a different virtual RF neighborhood
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IAP's send updates which includes density map, working channel, and current associated clients count in that radio (sum of all vaps) in the form of Information Element (IE) within the probe request packets. Once the AP receives the update, it lists all the density maps in the database, and compare to my own density map. If the two density maps are 75%+ match, (which is controlled by "SLB Matching Interval" configuration parameter) the neighbor is in my virtual RF neighborhood.
show ap debug spectrum-load-balancing <x>" helps us to understand the RF neighborhood.
(Where, x stands for radio: 0 or 1. 0 is for 5.GHz and 1 is for 2.4GHz)
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
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. |