This happens when UE lost the radi connection suddenly and attempting for re-establishment
This requires a quick cell reselection and send request to UTRAN
Once UE lost connection, it starts this procedureby starting timers T301,T314/315.
Failure of the timers(expires) , leads Ue state to Idle state
Here UE should go for new cell as the previous cell regarded as not-usable. Here UE sends RRCConncetionReestablishment and ends with _Complete to N/w.