A. Socket
B. Pipe
C. Port
D. Machine
An endpoint of an inter-process communication (IPC) flow across a computer network is typically referred to as a socket.
In network communication, a socket represents a communication endpoint between two processes, often running on different computers. Sockets allow processes to communicate with each other by sending and receiving data. They are identified by a combination of IP address and port number, which together uniquely identify the communication channel on each end of the connection.