Performance comparison of adaptive routing algorithms in the star interconnection network

The star graph was introduced as an attractive alternative to the well-known hypercube and its properties have been well studied in the past. Most of these studies have focused on topological properties and algorithmic aspects of this network. In this paper, the performance of nine fully-adaptive routing algorithms in the star network is studied under uniform (with and without locality) and hotspot traffic patterns. The performance factors considered are the average message latency and network utilization. We consider three basic routing algorithms (two hop scheme routing algorithms: positive-hop and negative-hop, and Misic's routing algorithm) and two other improved sets of improved algorithms based on the basic algorithms. The improved algorithms are the result of applying simple modifications to the basic algorithms. Simulation results show that for uniform (with and without locality) and hotspot traffic (with a low hot-spot portion) patterns, the first set of improved routing algorithms yields a better performance compared to the basic algorithms. The second set of improved routing algorithms outperforms the other two sets (the basic set and the first set of improved algorithms) under different working conditions.