A socket is basically an end point of a communication link between two applications. Sockets that extend over a network connect two or more applications running oncomputers attached to the network. A sockettwo addresses:. Sockets provide acommunication channel between one or more systems. There aresockets separately using TCP and UDP.
A．E-mail address and IP address B．MAC address and port address C．MAC address and IP address D．port number and IP address