This object is the threshold that triggers this specific association into its mildest, level-1 congestion state. Being the earliest and most sensitive of the three onset thresholds, it catches a backlog starting to build on this one link before it becomes severe, giving the earliest possible warning that this particular peer relationship is starting to fall behind. An association whose queue depth frequently crosses this level-1 onset threshold, even if it rarely reaches level 2 or 3, is showing early, recurring signs of mild congestion worth watching before it worsens.