An IPv4 address is a unique and logical network layer identifier that is assigned to each device on an IP network. It is a 32-bit identifier that consists of a network portion and host portion. The address format is as follows:

The network ID is used to identify the network in which the host resides. All nodes within the same network will share the same network ID. The host ID is used to identify the host within the network. Each node within the network will have a unique host ID. An IP address is always assigned with a subnet mask that identifies the network ID portion of the address. For example, the IP address 10.0.0.1 with a subnet mask of 255.255.255.0 denotes that the first three octets are the network ID and the last octet is the host ID.

While the size of the IPv4 address is 32-bits, the syntax used to represent the address is based on dotted decimal. The 32-bits are split into four octets and each octet is represented as a decimal value with a dot as demarcation.

There are three types of IPv4 addresses, outlined as follows:

• Unicast address: Used for point-to-point communication where data is sent from one node to one receiver in the same or different network. The address range for unicast is from 1.0.0.0 to 223.255.255.255.
• Multicast address: Used for point-to-multipoint communication where data is sent from one node to multiple receivers in the same or different network. The address range for multicast is from 224.0.0.0 to 239.255.255.255.
• Broadcast address: Used for point-to-multipoint communication where the data is sent from one node to all receivers in the same network. The last IP address in each subnet is the broadcast address. The address 255.255.255.255 is known as the limited broadcast address.