The BeagleBone has an Ethernet, or IEEE 802.3, connection. This provides a physical layer over which TCP/IP is implemented. TCP/IP, or Transmission Control Protocol/Internet Protocol, is a suite of networking layers that makes up the base of what we call the Internet. It is named after its two most important layers, TCP, which provides error-checked data transfer between endpoints, and IP, which provides routing of packets between hosts based on their IP addresses.

Pretty much all modern operating systems provide interfaces called network sockets, which are created and used to abstract an Internet connection using a model like TCP/IP. A socket is defined by its protocol (for example, TCP), its local IP address, and its local port number. A port is a software abstraction that allows any number of processes on a computer with a single IP address to exchange data over the network independently of each other, by each having their own unique ID, called a port number. Once a connection has...