Network Class
Addresses Required
Addresses Available
Addresses Wasted
A
100
16,777,214
16,777,114
B
100
00,065,534
00,065,434
C
100
00,000,254
00,000,154
Now multiply each entry in Table 2-3 by the 50 networks that are required and you can easily see that regardless of which address class we choose, an enormous number of IP addresses will be wasted. Also, if we are to have connectivity to the Internet, then the network will have to advertise 50 networks to the Internet routers. Multiply that by the number of campuses in the world and you have a situation where the size of the Internet routing tables becomes unmanageable. How do we overcome these problems? In a word, subnetting.