In network terminology a port can refer to a physical jack.
Particularly, it can refer to the many jacks on a switch or
repeater. For example, an "8 port ethernet switch" is a switch
with 8 ethernet jacks.  Alternatively, ports are used by the UDP
and TCP protocols to multiplex. Each host running IP has 65536
UDP ports and 65536 TCP ports. Data transfers occur between the
IP address and port of one host to the IP address and port of
another host. Servers will listen on special well-known ports.
Clients will allocate ephemeral ports, and send data to the
server's well-known ports from there.  As an aside, IP does not
have links. IP and UDP are both connectionless protocol. TCP,
however, is a connection-oriented protocol and does establish
links.