The value of tAdvCfgAbvOffCapRate specifies the explicit number of
kilobits-per-second that should be used as the limit to the child's
fair share increase to the operational PIR.
When the value of tAdvCfgAbvOffCapRate is set to '0', the system
disables the fair share increase function and configures the actual
distribution rate.
When the value of tAdvCfgAbvOffCapRate is set to '-1', it means maximum
rate.