“network: noun; 6. Telecommunications, Computers. a system containing any combination of computers ... interconnected by telecommunication equipment or cables: used to transmit or receive information.”
The core code in Apple’s iOS and OS X operating systems is UNIX, and it provides the basic networking functions that all the higher-level Apple frameworks use. Your apps can also reach down to the UNIX networking APIs and use them directly. In this chapter I will present the basics of networking in general, and then present the standard UNIX library routines available in iOS and OS X for creating network communications between machines and for transferring information through network connections.