1. The technique used by layered protocols in which a layer adds header information to the protocol data unit (PDU) from the layer above. As an example, in Internet terminology, a packet would contain a header from the physical layer, followed by a header from the network layer (IP), followed by a header from the transport layer (TCP), followed by the application protocol data. 2. The ability to provide users with a well-defined interface to a set of functions in a way which hides their internal workings. In href="module.php?name=Lexikon&file=search&eid=1&query=object-oriented programming">object-oriented programming, the technique of keeping together data structures and the methods (procedures) which act on them. (1998-09-07)
