A network can represent the sequence of activities in a project or the sequence of a single activity within a project. You can graphically display various structural elements of a project and their interdependencies in the Project System.

During the life of a project, networks are used as a basis for planning, analyzing, controlling and monitoring schedules, dates, and resources.(such as personnel, machines, PRTs, materials, documents, and drawings).

The following are examples of the types of questions you can answer with the information you get from a network:

• Where are we unclear on the processes in the project and what are the possible consequences?

• Where are the scheduling uncertainties and how significant are they?

• When and in what amount do we incur costs and make expenditures for this project?

• When and in what quantity do resources have to be available so that we can keep to the schedule?

In the Project System networks are activity-on-mode networks.

The essential components of a network are:

• Activities

• Relationships between the activities

The most important data describing an activity in the Project System is:

• Work center in which the activity is to be carried out

• Duration of the activity

• Start and finish dates for the activity

• Resources required to carry out the activity

• Texts and documents describing the activity

There is usually a reason for a specific sequence of activities in a network. For example, there may be technical dependencies between individual activities. These dependencies are represented by relationships in which one activity is the predecessor or the successor of another activity.

The relationship type specifies how the individual activities are linked with each other:

• Finish - Start (FS) Relationship

• Start - Start (SS) Relationship

• Finish - Finish (FF) Relationship

• Start - Finish (SF) Relationship