On routing clos networks

Clos networks are rearrangeable networks that have been proven to realize any permutation of the inputs onto the outputs. Routing algorithms create the switch settings within the network for the connections for a particular permutation. Present parallel routing algorithms use edge coloring algorithms applied to the bipartite representation of Benes and Clos networks. None of these algorithms can be executed on a Clos network system. Since a Clos network system should be able to route itself, we develop parallel algorithms which can be implemented using the Clos network instead of the shared memory or fixed networks of present algorithms. We develop two parallel sorting algorithms with fixed routings for Benes and Clos networks. These algorithms are used to provide access methods for the parallel routing algorithms. Experimental results are given to show that the serial edge-coloring algorithm from Carpinelli and Oruc does not route all permutations. We find that their algorithm can be used for small permutations but as the size of the network increases fewer permutations can routed. A diagram for Benes networks is developed from Knuth diagrams for sorting networks. This allows a depiction of the transformation of the input addresses into the output addresses and the functions that describe how the settings are derived for the different stages.