多 Hub 级连方式效率、单点失效

结点层次 | 度为 2 | 度为 4 | 度为 8

------- | -------- | -------- | --------

t = 1 | t = 126 | t = 5,460 | t = 299,592

t = 2 | t = 142 | t = 3,028 | t = 79,432

t = 3 | t = 78 | t = 820 | t = 10,440

t = 4 | t = 28 | t = 168 | t = 1,168

平均路径长度 | t = 3.50 | t = 4.80 | t = 5.44