Frequency hopping

Hello everybody What happens when a mobile station is in a cell that uses hopping, but the mobile locks to that cell (for instance using the function of the engineering menu of a BB)? Is the hopping mandatory or the ms can continue working also without it? Does osmocom support hopping? What are the commands of the mobile interface (if they exist) to show how the hopping is going? Is it possible to lock with osmocom too? Thanks for the answers. Dario.