Abstract We propose a new parallel topology discovery algorithm for irregular, mesh-connected networks with unidirectional links and wormhole routing. An algorithm of this type was developed for the ATOMIC high speed local area network to avoid the need for manually updating routing tables. Similar needs may arise in wireless networks where channels may be unidirectional because of limited transmission power, multipath, and similar effects. Like the ATOMIC topology discovery algorithm, our algorithm accumulates a map of the network at a distinguished node called the Address Consultant. However, our algorithm is much faster. In addition, our algorithm is more general, because it can correctly resolve topologies that contain multiple links between the same nodes. We implemented both algorithms in a concurrent simulation environment, and tested them on a variety of topologies.