Provide a difference between Port address, logical and physical address.

Port addressing:

            Computer often run several process at the same time. For this reason process-to-process delivery means delivery not only from one computer to the next but also from a specific process on one computer to a specific process on another. The transport layer must there for include a type of address called a port address.

Logical Address:

            In computer networks, a logical address refers to a network layer address such as an IP address, an X.25/X.121 or IPX address.

In computer architectures, a logical address or virtual address is a memory location accessed by an application program in a system with virtual memory such that intervening computer hardware and/or software maps the virtual address to real (physical) memory. During the course of execution of an application, the same virtual address may be mapped to many different physical addresses as data and programs are paged out and paged in to other locations.

Physical Addressing:

            If frames are to be distributed to different systems on the network, the data link layer adds a header to the frame to define the sender or receiver of the frame. If the frame is intended for a system outside the sender’s network, the receiver is the address o connecting device that connects the network to the next one.