Project Network is the diagrammatic representation of interconnected activities in project. Activities in a project network are either successor or predecessor activities. Project Network is also known as Precedence Diagram. Project Networks are composed of Nodes and arcs. Time sequenced from Left to Right. All activities except start and finish time must have at least one predecessor and one successor.
So a good network diagram will be a step-by-step representation of the project.
There are two types of network diagrams: The Arrow Diagram (activity on arrow) and the Precedence diagram (activity of node). The arrow diagram depicts nodes for events and arrows for activities. The precedence diagram depicts activities in the order they occur.
A B relationship represents an event node. These event nodes refer to an instant when an activity is started or completed. An event node occurs only when all activities entering the node have been completed. The arrow represents the activity that takes place during the event. For example, if a task in a project were “research competition’s ad campaign,” then the event nodes would designate the start and finish of this activity whereas the arrow would designate the activity itself.
Using the arrow and node method, you can depict project dependencies. In the diagram to the right, you see that Event C depends upon activities from Events A and B to be completed, and Event D depends upon Event C’s activities to be completed.
Dotted lines with arrows represent “dummy arrows.” Rather than depict a dependency between two items, these arrows depict a logical relationship. Dummy arrows have no duration. They do not depict an activity. Instead, they transfer logic from one event node to another.
Network diagrams are used whenever project management occurs. Because these project management tools are so useful, they can help project management teams to visualize the planning they have put time and effort