A comparative performance analysis of n-cubes and star graphs

Many theoretical-based comparison studies, relying on the graph theoretical viewpoints with using structural and algorithmic properties, have been conducted for the hypercube and the star graph. None of these studies, however, considered real working conditions and implementation limits. We have compared the performance of the star and hypercube networks for different message length and virtual channels and considered two implementation constraints, namely the constant bisection bandwidth and constant node pin-out. We use two accurate analytical models already proposed for the star graph and hypercube and implement the parameter changes imposed by technological implementation constraints. The comparison results reveal that the star graph has a better performance compared to the equivalent hypercube under light traffic loads while the opposite conclusion is reached for heavy traffic loads. The hypercube with more channels compared to its equivalent star graph saturates later showing that it can bear heavier traffic loads