Open Systems Interconnect
Open Systems Interconnection
Nearby terms:
OpenStep « open switch « Open System Architecture «
Open Systems Interconnect » Open Systems
Interconnection » Open Telecom Platform » Open
Trading Protocol
Open Systems Interconnection
<networking> (OSI-RM, OSI Reference Model, seven layer model) A model of
network architecture and a suite of protocols (a protocol stack) to implement
it, developed by ISO in 1978 as a framework for international standards in
heterogeneous computer network architecture.
The OSI architecture is split between seven layers, from lowest to highest: 1
physical layer, 2 data link layer, 3 network layer, 4 transport layer, 5 session
layer, 6 presentation layer, 7 application layer.
Each layer uses the layer immediately below it and provides a service to the
layer above. In some implementations a layer may itself be composed of
sub-layers.
OSI is the umbrella name for a series of non-proprietary protocols and
specifications, comprising, among others, the OSI Reference Model, ASN.1
(Abstract Syntax Notation 1), BER (Basic Encoding Rules), CMIP and CMIS (Common
Management Information Protocol and Services), X.400 (Message Handling System,
or MHS), X.500 (Directory Service), Z39.50 (search and retrieval protocol used
by WAIS), and many others. Apart from its actual application to real protocols,
it also serves as a useful teaching model.
(2004-02-13)
Nearby terms:
open switch « Open System Architecture « Open
Systems Interconnect « Open Systems
Interconnection » Open Telecom Platform » Open
Trading Protocol » OpenTransport
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