The value of tHsmdaSlopeLoMaxProbability specifies the drop
probability, as a percentage, when the Hsmda queue depth reaches
tHsmdaSlopeLoMaxDepth. The drop increases steadily from 0 at
the tHsmdaSlopeLoStartDepth up to the tHsmdaSlopeLoMaxProbability
at the tHsmdaSlopeLoMaxDepth.