This section reviews the concepts of classful IP networks (A,B,C)
Chapter examines how to begin with a single IP address and then determine the following facts:
- default mask
- number of network bits
- number of host bits
- number of host addresses in the network
- network ID
- network broadcast address
- first and last usable address in the network
IPv4 network classes and related facts:
- IPv4 defines five address classes
- three of classes (ABC) consist of unicast IP addresses.
- unicast addresses identify a single host or interface so that the address uniquely identifies the device in private network
- Class D addresses serve as multicast addresses, so that one packet sent to class D multicast IPv4 address can actually be delivered to multiple hosts
- Class E were intended for experimentation, but were changed to simply be reserved for future use.
- Class can be identified based on the value of the first octet of the address:
0.0.0.0 are reserved and 127.0.0.0 also
First, Class B network numbers range from 126.96.36.199 to 188.8.131.52, for a total of 214 networks.