Class B addresses
class B: assigned to medium-sized to large-sized networks
- the two high order bits in a class B address are set to binary 1 0
- default subnet mask is /16
- valid network addresses range from 128.0.0.0 to 191.255.0.0/16
- allows for 16,384 networks and 65,534 hosts per network
- in practice it would be further subnetted
Class C addresses
class C: assigned to small networks
- the three high order bits in a class C address are set to binary 1 1 0
- default subnet mask is /24
- valid network addresses range from 192.0.0.0 to 223.255.255.0/24
- allows for 2,097,152 networks and 254 hosts per network
- could be allocated as if for real world network, or subnetted into smaller subnets
Note on Private Addresses
- there are reserved Private Addresses in each class
- valid to be assigned to hosts but they are not routable on the public internet
- originally designed for hosts in a private network with no internet connectivity
- class A: 10.0.0.0 to 10.255.255.255
- class B: 172.16.0.0 to 172.31.255.255
- class A: 192.168.0.0 to 192.168.255.255