Module 11: IPv4 Addressing

Assigning an IPv4 address to a host requires the following:

IPv4 address

Subnet mask

IPv4 address

This is the unique address of the host.

Subnet mask

This is used to identify the network/host portion of the IPv4 address.

Within each network are three types of IP addresses:

Network address

Host addresses

Broadcast address

Class A (0.0.0.0/8 to 127.0.0.0/8)

Designed to support extremely large networks with more than 16 million host addresses. Class A used a fixed /8 prefix with the first octet to indicate the network address and the remaining three octets for host addresses (more than 16 million host addresses per network).

Class B (128.0.0.0 /16 - 191.255.0.0 /16)

Designed to support the needs of moderate to large size networks with up to approximately 65,000 host addresses. Class B used a fixed /16 prefix with the two high-order octets to indicate the network address and the remaining two octets for host addresses (more than 65,000 host addresses per network).

Class C (192.0.0.0 /24 - 223.255.255.0 /24)

Designed to support small networks with a maximum of 254 hosts. Class C used a fixed /24 prefix with the first three octets to indicate the network and the remaining octet for the host addresses (only 254 host addresses per network).