Reference Manual

Redpine Signals, Inc. Proprietary and Confidential Page 82
RS9116 n-Link Linux and Android
Technical Reference Manual
Version 2.0
14 Background Scan Parameters
This section describes the various parameters for the Background scan commands that can be sent to the n-Link Client
using the onebox_util program.
• <bgscan_threshold>: The Background scan threshold is referred to as the RSSI Upper Threshold. At every background
scan interval (configured via <periodicity>), the n-Link® module decides whether to initiate or not to initiate a
background scan based on the connected Access Point’s RSSI. The module initiates a background scan if the RSSI of
the connected Access Point is below this threshold. The input value should be the absolute value in dBm.
• <rssi_tolerance_threshold>: If the difference between the current RSSI value of the connected Access Point and the
RSSI value of the Access Point from the previous background scan is greater than the RSSI Tolerance Threshold, then
the module performs a background scan. Assigning a large value to this field will eliminate this method of triggering
background scans.
• <periodicity>: This parameter specifies the interval between the background scans. The unit of this field is seconds.
Setting the value of this field as 0 will disable background scans.
• <active_scan_duration>: This parameter determines the duration of the active scan in each channel during the
Background scan process. The recommended value for this parameter is 20ms for quicker Background scan operation
and uninterrupted throughput. The maximum allowed value for this parameter is 255ms.
• <passive_scan_duration>: This parameter determines the duration of the passive scan in each DFS channel. If an
active scan is enabled in a DFS channel and a beacon or probe response is received during that period, the module
converts the passive scan into an active scan and waits through the duration specified by the <active_scan_duration>
parameter. During a passive scan, if any beacon is recieved in a channel, then the recommended value for this
parameter will be 100ms. The active scan in DFS channel can be enabled through Background scan probe request.
Active scanning will be performed only if channel switch IE (Information Element) is not present in the received
beacon or probe response packets. The maximum allowed value for this parameter is 255ms.
• <two_probe_enable>: If this feature is enabled, the Client sends two probe requests to the Access Point. This is useful
when scanning is carried out in channels with high traffic. The valid values are
1. 0 – Disable
2. 1 – Enable
• <num_of_bgscan_channels>: Specifies the number of Background scan channels. The n-Link® module supports up to
24 channels.
• <channels_to_scan>: The list of channels in which Background scan has to be performed