The tx-power-control example can be used to check the link between a node and an rpl-border-router. After a link is established, the following coap rresources are exposed:
node: Set-Tx-Power: a PUT/POST resource to set the TX power of the device. The firmware in the device will set the TX power to the nearest available value. Get-Tx-Power: a GET resource to retrieve the actual Tx power that is set.
rpl-border-router: Get-RSSI: a GET resource that shows the detected energy level Get-Last-RSSI:a GET resource that shows the RSSI of the last received packet. When there is only 1 node, Get-Last-RSSI will show the effect of changing the TX power level on that node.