Controller Based WLANs

Environment : This article applies to Aruba Mobility Controllers running ArubaOS version 6.3.0.0.

Pre Aruba OS 6.3 the decision on where to steer the client is just a onetime decisions during client association and the steering works by virtually hiding the AP from the client so that the clients get connected to the nearby APs, also there are multiple features which does independent decisions.

All these maximized client performance and enhance the stability but the results were not deterministic

With Aurba OS 6.3.x features such as Spectrum Load Balancing, Hand-off Assist, Band Balancing and Band Steering are now integrated into a Single feature called Client Match which makes cohesive decisions on mapping clients to best APs also Steering and balancing decisions are now continuous and consistent, not just Applied at the time of Client association

Client Match gathers and aggregates the information on the client-view of RF Environment  as well as monitors client health. The Band Steering and Band balancing Trigger Algorithm runs periodically, even after client is associated and can trigger a client to move to a different AP as needed

 Working of Band Balance 

• The Band Balance Trigger maintain a client ratio for G:A radios as 1:4 on each AP

• It stop band-steering clients to 5GHz if,

1. Total number of clients on both radios is greater than 15   

2. At least 3 clients in G radio and number of clients in A radio > 4*(number of clients in G radios)

Working of Band Steering

• Band Steer Trigger Identify clients that are dual-band capable (having both 2.4G and 5G radios in their virtual beacon report)

• If a client SNR is above a good threshold (default: 25dB SNR),

• It does nothing if the client is associated at 5GHz

• If the client is associated at 2.4G then it move the client to 5GHz on the same AP only if the 5G radio signal is >-70dBm

• It do not move the client  if band-balance logic is matched