This paper considers a hub network design problem where the network service area partitioned into the predetermined zones (represented by node clusters) is given, and non-stop (direct link) service is allowed. The objective is to design a hub network under non-restrictive networking policy by determining all the required hub locations in the predetermined zones and also all the terminal-to-terminal routes such that the total network cost (hub construction and dow transportation cost) is minimized. For the design problem, a dual-based solution approach is proposed and tested for its effectiveness with numerical examples. (C) 2001 Elsevier Science B.V. All rights reserved.