Why do companies analyze their logistics systems from the perspective of nodes and links?

From a node-link perspective, the complexity of logistics systems can vary enormously. A node system might use a simple link from suppliers to a combined plant and warehouse and then to customers in a relatively small market area. At the other end of the spectrum are large, multiple-product organizations with multiple plant and warehouse locations. The complex transportation networks of the latter can include three or four different modes and perhaps private as well as for-hire transportation. The node-link perspective, in allowing analysis of a logistics system's two basic elements, represents a convenient basis for seeking possible system improvements. As has been noted, the complexity of a logistics system often relates directly to the various time and distance relationships between the nodes and the links and to the regularity, predictability, and volume of flow of goods entering, leaving, and moving within the system.