•Internal implies that the transition occurs without exiting or entering the source state. Thus, it does not cause a state change. This means that the entry or exit condition of the source state will not be invoked. An internal transition can be taken even if the state chart is in one or more regions nested within this state.
•Local implies that the transition, if triggered, will not exit the composite (source) state, but rather is applied to any state within the composite state, and these will be exited and entered.
•External implies that the transition, if triggered, exits the composite (source) state.