Networking & System

Computer network programming involves writing computer programs that enable processes to communicate with each other across a computer network.
Very generally, most of communications can be divided into connection-oriented, and connectionless. Whether a communication is a connection-oriented, or connectionless, is defined by the communication protocol, and not by application programming interface (API). Examples of the connection-oriented protocols include Transmission Control Protocol (TCP) and Sequenced Packet Exchange (SPX), and examples of connectionless protocols include User Datagram Protocol (UDP), “raw IP”, and Internetwork Packet Exchange (IPX).
For connection-oriented communications, communication parties usually have different roles. One party is usually waiting for incoming connections; this party is usually referred to as “server”. Another party is the one which initiates connection; this party is usually referred to as “client”.
For connectionless communications, one party (“server”) is usually waiting for an incoming packet, and another party (“client”) is usually understood as the one which sends an unsolicited packet to “server”.
System programming (or systems programming) is the activity of programming computer system software. The primary distinguishing characteristic of systems programming when compared to application programming is that application programming aims to produce software which provides services to the user directly (e.g. word processor), whereas systems programming aims to produce software and software platforms which provide services to other software, are performance constrained, or both (e.g. operating systems, computational science applications, game engines and AAA video games, industrial automation, and software as a service applications).
System programming requires a great degree of hardware awareness. Its goal is to achieve efficient use of available resources, either because the software itself is performance critical (AAA video games) or because even small efficiency improvements directly transform into significant monetary savings for the service provider (cloud based word processors).