(1) See
Open Source Initiative.
(2) (
Open
System
Interconnection) An ISO standard for worldwide communications that defines a protocol framework in seven layers. OSI functionality exists in all communications systems, although two or three layers may be incorporated into one (see
OSI model). Control is passed from the top application layer to the bottom layer, out over the network to the bottom layer of the receiving station and back up to the application layer. See
ISO.
Never Completely Defined
OSI was too loosely defined to become a single standard. Nevertheless, the model serves to teach communications, and TCP/IP, the global networking standard, embodies most of the OSI layers (for a comparison, see
TCP/IP).