Logical addresses are necessary for universal communications that are independent of underlying physical networks. Physical addresses are not adequate in an internetwork environment where different networks can have different address formats. A universal addressing system is needed in which each host can be identified uniquely, regardless of the underlying physical network.
A logical address in the Internet is currently a 32-bit address that is IPv4 that can uniquely define a host connected to the Internet. No two publicly addressed and visible hosts on the Internet can have the same IP address.
The Physical Addressing will change from hop to hop, but the logical addresses remain the same.
The logical addresses can be either unicast (one single recipient), multicast (a group of recipients), or broadcast (all systems in the network). There are limitations on broad-cast addresses.