A mathematical model that represents connection structures in an abstract fashion. It consists of ''nodes'' and of ''edges'', where the edges represent connections between nodes. In a specific application, nodes as well as edges may be assigned values, such as weights, costs or distances.

ETSI GR ENI 004 collection of nodes, where some subset of the nodes is connected.

NOTE: Visually, a node is a "point" and a connection is a "line", called an "edge". For the purposes of ENI, any graph may be directed, weighted or both.