This Counter32 increments when an ack arrives while there is data waiting in the hold queue ready to be sent immediately, meaning the transport is actively working through a backlog rather than sitting idle. A rising HoldCountRatio3 relative to the other two ratios tells an admin the connection is being kept busy and is not the constraint. For example, during a sustained bulk transfer where the application keeps the pipe full, most of the ack-driven increments would land in HoldCountRatio3 rather than Ratio1 or Ratio2.