"A computer network diagram is a schematic depicting the nodes and connections amongst nodes in a computer network or, more generally, any telecommunications network. ...
Depending on whether the diagram is intended for formal or informal use, certain details may be lacking and must be determined from context. ...
At different scales diagrams may represent various levels of network granularity. At the LAN level, individual nodes may represent individual physical devices, such as hubs or file servers, while at the WAN level, individual nodes may represent entire cities. In addition, when the scope of a diagram crosses the common LAN/ MAN/ WAN boundaries, representative hypothetical devices may be depicted instead of showing all actually existing nodes." [Computer network diagram. Wikipedia]
The Cisco computer network diagram example "Network organization chart" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Cisco Network Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.