What you mean by Ip address and why it is necessary for an host to have an ipaddress for communication?
Ip address and its necessary
Define Ip Address:
An identifier for a computer or device on a TCP/IP network.
Why it is necessary:
The smallest subnet that has no more subdivisions within it is considered a single "broadcast domain", which directly correlates to a single LAN(local area network) segment on an Ethernet switch. The broadcast domain serves an important function because this is where devices on a network communicate directly with each other's MAC addresses, which don't route across multiple subnets, let alone the entire Internet. MAC address communications are limited to a smaller network because they rely on ARP broadcasting to find their way around, and broadcasting can be scaled only so much before the amount of broadcast traffic brings down the entire network with sheer broacast noise. For this reason, the most common smallest subnet is 8 bits, or precisely a sing octet, although it can be smaller or slightly larger.