This paper investigates a planar solution of the optimization problem that appears in the design of degree-three connected stucture for local area networks and also in the interconnection network for parallel machines. For every digraph on N vertices there are several solutions that produce the minimum values of the diameter and average distance between vertices. The geometrical approach used to characterize the optimal solutions greatly facilities the study of routing and reliability questions.
Singapore ICCS/ISITA '92. 'Communications on the Move', pp.1391~1395