A design is presented for a set of VLSI building blocks that permit the construction of high-bandwidth networks of arbitrary topology, providing the modularity needed for incremental expansibility. The proposed VLSI switching components support message-based, virtual circuit communications over dedicated, time-multiplexed links. The simplest representative is the Y-component, a message switch with only three ports. Its usefulness for the construction of a variety of networks is shown with the analysis of simplified models. Some simulation results are presented that corroborate these findings.