A topology node is an abstract representation of a star system. Each has the following properties:
At the beginning of the game, the entire set of topology nodes is created. This set of nodes, called the “topology” for short, defines all the possible systems accessible to the player in that game.
When a system is created, the topology node for that system is consulted to determine the SystemType to use, the name of the system, and the set of stargates in that system.