Whenever handover procedure gets failed, UE triggers re-establishment towards target cell or source cell based on the signal strength. To make handover procedure successful, few parameters such as hysteresis, RSRP etc are configured with correct value so that handover decision is taken at source eNodeB at the right time and it avoids handover failure.
If RRC re-establishment occurs as handover failure at the source eNodeB then it is considered as too early handover. It means target cell radio strength was not good enough to make handover successful for the UE. In other case when re-establishment comes to target cell it means handover was triggered late from source cell.
