## Abstract

We introduce a novel graph called a host-switch graph, which consists of host vertices and switch vertices. Using host-switch graphs, we formulate a graph problem called an order/radix problem (ORP) for designing low end-to-end latency interconnection networks. Our focus is on reducing the host-to-host average shortest path length (h-ASPL), since the shortest path length between hosts in a host-switch graph corresponds to the end-to-end latency of a network. We hence define ORP as follows: given order (the number of hosts) and radix (the number of ports per switch), find a host-switch graph with the minimum h-ASPL. We demonstrate that the optimal number of switches can mathematically be predicted. On the basis of the prediction, we carry out a randomized algorithm to find a host-switch graph with the minimum h-ASPL. Interestingly, our solutions include a host-switch graph such that switches have the different number of hosts. We then apply host-switch graphs to interconnection networks and evaluate them practically. As compared with the three conventional interconnection networks (the torus, the dragonfly, and the fat-tree), we demonstrate that our networks provide higher performance while the number of switches can decrease.

Original language | English |
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Title of host publication | Proceedings - 46th International Conference on Parallel Processing, ICPP 2017 |

Publisher | Institute of Electrical and Electronics Engineers Inc. |

Pages | 322-331 |

Number of pages | 10 |

ISBN (Electronic) | 9781538610428 |

DOIs | |

Publication status | Published - 2017 Sep 1 |

Event | 46th International Conference on Parallel Processing, ICPP 2017 - Bristol, United Kingdom Duration: 2017 Aug 14 → 2017 Aug 17 |

### Other

Other | 46th International Conference on Parallel Processing, ICPP 2017 |
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Country | United Kingdom |

City | Bristol |

Period | 17/8/14 → 17/8/17 |

## Keywords

- Average shortest path length
- Graph theory
- Interconnection network
- Network topology
- Optimization

## ASJC Scopus subject areas

- Software
- Mathematics(all)
- Hardware and Architecture