A conceptual model that provides the common basis for the coordination of standards proposed by the International Organisation for Standardisation for the purpose of systems interconnection. Has a derived version: the IP protocol suite.

Has seven layers in total, namely the:

  1. physical layer;
  2. data link layer;
  3. network layer;
  4. transport layer;
  5. session layer;
  6. presentation layer; and
  7. application layer.