IP v4 Addressing System
What is the need of MAC address if we have HID to identify a host??
MAC address is the permanent address where as ip address is static.Your ip changes after some time at that time we check the MAC address from the router and see the present ip address of that system and we send the data to that system.
public IP's efficiently utilize with the help of private IP's
like that college campus uses public IP with privates IP's.
in a network host id are unique