Complex sentence: In multistage topologies, higher level switching nodes connect to lower level switching nodes as shown in figure 1, where switching nodes in rank 0 connect to processor nodes directly while switching nodes in rank 1 connect to switching nodes in rank 0.
Split into simpler sentences: In multistage topologies, higher level switching nodes connect to lower level switching nodes as shown in figure 1. Switching nodes in rank 0 connect to processor nodes directly while switching nodes in rank 1 connect to switching nodes in rank 0.