Primavera P6 baseline link with current planned schedule

Hello,

I looking for a solution concerning primavera P6.

I wonder know what is the link between baseline activities & the current planned schedule, I mean not the link like SS, FF, etc, but is the criteria (field) used by the activity in the baseline to recognize the activity in the current planned schedule.

For example in P3 it was the activity ID, but in P6 it seems not to be the same. Indeed when you change the activity ID of an activity, the baseline remain and don't desepear like in P3.

Does anyone has the clue?

Thanks a lot