由子网掩码换算子网前缀长度
| 子网掩码 |
子网前缀长度 |
| 255.255.255.255 |
32 |
| 255.255.255.254 |
31 |
| 255.255.255.252 |
30 |
| 255.255.255.248 |
29 |
| 255.255.255.240 |
28 |
| 255.255.255.224 |
27 |
| 255.255.255.192 |
26 |
| 255.255.255.128 |
25 |
| 255.255.255.0 |
24 |
| 255.255.254.0 |
23 |
| 255.255.252.0 |
22 |
| 255.255.248.0 |
21 |
| 255.255.240.0 |
20 |
| 255.255.224.0 |
19 |
| 255.255.192.0 |
18 |
| 255.255.128.0 |
17 |
| 255.255.0.0 |
16 |
| 255.254.0.0 |
15 |
| 255.252.0.0 |
14 |
| 255.248.0.0 |
13 |
| 255.240.0.0 |
12 |
| 255.224.0.0 |
11 |
| 255.192.0.0 |
10 |
| 255.128.0.0 |
9 |
| 255.0.0.0 |
8 |
| 254.0.0.0 |
7 |
| 252.0.0.0 |
6 |
| 248.0.0.0 |
5 |
| 240.0.0.0 |
4 |
| 224.0.0.0 |
3 |
| 192.0.0.0 |
2 |
| 128.0.0.0 |
1 |
| 0.0.0.0 |
0 |