Complex sentence: The topology of the Infiniband network is a two-dimensional hyper-crossbar, i.e., a two-dimensional mesh of Infiniband switches is built, and the two Infiniband ports of a node are connected to one switch in each of the dimensions.
Split into simpler sentences: The topology of the Infiniband network is a two-dimensional hyper-crossbar. This means that a two-dimensional mesh of Infiniband switches is built, and the two Infiniband ports of a node are connected to one switch in each of the dimensions.