Constraints are applied to your tasks to impose restrictions on the way that the task's start and finish dates are calculated. There are 8 types of constraints, which can be bucketed into the following 3 categories:
Constraint Name | Constraint Category | Description |
---|---|---|
As Soon As Possible (ASAP) | Flexible Constraint | Schedules the task to begin as early as possible. This is the default constraint for new Auto-scheduled tasks. For stand-alone tasks, this will always schedule tasks from the project's start date. |
As Late As Possible (ALAP) | Flexible Constraint | Schedules the task as late as possible, without delaying subsequent tasks. For stand-alone tasks, this will always schedule tasks backwards from the project's planned finish date. |
Start No Earlier Than (SNET) | Semi-flexible Constraint | Schedules the task to start on or after a specified date. Use this constraint to ensure that a task does not start before a specified date. |
Start No Later Than (SNLT) | Semi-flexible Constraint | Schedules the task to start on or before a specified date. Use this constraint to ensure that a task does not start after a specified date. |
Finish No Earlier Than (FNET) | Semi-flexible Constraint | Schedules the task to finish on or after a specified date. Use this constraint to ensure that a task does not finish before a particular date. |
Finish No Later Than (FNLT) | Semi-flexible Constraint | Schedules the task to finish on or before a specified date. Use this constraint to ensure that a task does not finish after a particular date. |
Must Start On (MSO) | Inflexible Constraint | Schedules the task to start on a specified date. |
Must Finish On (MFO) | Inflexible Constraint | Schedules the task to finish on a specified date. |
Constraints have higher precedence than task dependency, i.e. if a task is a successor task and also has a constraint date set, then the start/finish dates of the task will be determined by its constraint (type and date). |