Final answer:
A network structure with an average path length close to 2 is indicative of a small-world network, such as the Watts-Strogatz model.
Step-by-step explanation:
A network structure with an average path length close to 2 is indicative of a small-world network. In a small-world network, most nodes are not directly connected, but the distance between any two nodes is relatively short. One example of a link-efficient network structure with an average path length close to 2 is the Watts-Strogatz model.
The Watts-Strogatz model is a random graph model that starts with a regular network and then rewires some edges randomly. This rewiring process increases the number of shortcuts and reduces the average path length while maintaining a high level of local clustering.