Open Systems Interconnection

Open Systems Interconnection
ISO seven layer model
Open Systems Interconnect
OSI Model
OSI Reference Model
OSI-RM
OSI seven layer model
seven layer model

   <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)