TCP/IP provides for process-to-process communication, which means
that calls need an addressing scheme that specifies both the physical
host connection (Host A and Host B in Figure 1) and the software process or
application (C, D, E, F, G, and H). The way this is done in TCP/IP
is for calls to specify the host by an internet address and the process by a port number. You may find internet addresses also referred to
elsewhere as internet protocol (IP) addresses or host IDs. Figure 1. How applications are addressed
