Abstract: Many cut-through switches, which can greatly reduce network latency, are commercially available for the construction of high-speed local area networks. The interconnection of cut-through switches provides an excellent network platform for high-performance workstation clusters. A novel deadlock-free adaptive routing algorithm is proposed to allow irregular interconnection of cut-through switches. The adaptive routing algorithm is based on two unidirectional adaptive trails constructed from two opposite unidirectional Eulerian trails. Some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity. Extensive simulation experiments based on a more realistic finite input source model are conducted to evaluate the network performance under different network parameters and traffic conditions. Both bimodal and bursty messages are considered. Such switch-based irregular networks are truly incrementally scalable and have potential to be reconfigured to adapt to the dynamics of network traffic conditions.