The authors describe a methodology for designing interconnected local area network/metropolitan area network (LAN-MAN) networks with the objective of minimizing the average network delay. They consider IEEE 802.3-5 LANs interconnected by transparent bridges. These bridges are required to form a spanning tree topology. The optimization algorithm for finding a minimum delay spanning tree topology is based on simulated annealing. In order to measure the quality of the solutions, a lower bound for the average network delay is found. The comparison of results with this lower bound and several other goodness measures shows that the solutions are not very far from the global minimum. The authors extend the present algorithm for finding minimum delay LAN-MAN topologies consisting of fiber distributed data interface (FDDI) MANs or switched multi-megabit data service (SMDS) interconnecting several clusters of bridged LANs.