Has anyone been able to trespass the China Great Wall on its early days? Any hun for example?

In the early days, the wall defended the central plain from the attacks of the northern tribes. Central plain was the winner of almost all the battles.
However, Khitan and Mongolian tribes broke this defensive line and invaded the central plain in different times. They established the Liao Dynasty (907-1125) and Qing Dynasty (1644-1911) respectively to control the whole nation.