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Pre-association Band steering:

a. When SNR RSSI of client probe request received by AP/Gateway in 2.4GHz band is more than the threshold, then AP blocks the 2.4GHz band for the client and informs client to probe request to 5GHz.

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a. Client has associated with a non-preferred band, SNR RSSI is checked if it is above threshold. If it is above threshold, client is disassociated from the band and Steered to preferred band using Pre-association procedure.

Post-association Band Steering

Description

RSSI is the Received Signal Strength of the probe request sent by the Client to the APs for connection establishment. RSSI will always be a negative value when converted to dbm.

As we already know, 5GHz Band has bigger channel Bandwidth and more number of channel occupancy when compared to 2.4GHz band. 5GHz provides good network connection to all the clients connected for a shorter distance, unlike 2.4GHz which is suitable for longer range networks.

RSSI which determines the signal strength of the client towards AP, can have a threshold value which will help in directing/deciding as to which band the client needs to be connected to. Signal strength indirectly indicates the distance of the client from AP. It is understood that as RSSI decreases, the distance of client device from the AP increases.

RSSI is determined by the iwconfig command

Image Added

Signal Level=37/100 is the RSSI in arbitrary unit, has to be converted to dbm.

Command to obtain Signal Level value:

iwconfig wlan0 | grep Signal | cut -d '=' -f3 | cut -d ' ' -f1

Based on Cisco chart for conversion of arbitary unit to dbm:

RSSI above 67: dbm = 1.2*RSSI – 123

or

RSSI between 36 and 66: dbm = 1.1*RSSI – 114.6

or

RSSI below 35: dbm = 1*RSSI - 112

RSSI threshold:

RSSI threshold is set to -100 by default, based on the Real time Box behaviour.

RSSI range:

-100 to 0

Sequence diagram

Architecture

• Layout

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