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• CCITT Rec. X.200 (11/1988) – REFERENCE MODEL OF OPEN SYSTEMS INTERCONNECTION FOR CCITT APPLICATIONS
• CONTENTS
• 0 Introduction
  • 0.1 About this Recommendation
• 1 Scope and field of application
  • 1.1 The scope of the Reference Model
  • 1.2 The application of the Reference Model
• 2 Definitions
• 3 Notation
• 4 Introduction to Open Systems Interconnection (OSI)
  • 4.1 Definitions
    • 4.1.1 real system
    • 4.1.2 real open system
    • 4.1.3 open system
    • 4.1.4 application-process
  • 4.2 Open Systems Interconnection environment
  • 4.3 Modelling the OSI environment
• 5 Concepts of a layered architecture
  • 5.1 Introduction
  • 5.2 Principles of layering
    • 5.2.1 Definitions
    • 5.2.2 Description
  • 5.3 Communication between peer entities
    • 5.3.1 Definitions
    • 5.3.2 Description
  • 5.4 Identifiers
    • 5.4.1 Definitions
    • 5.4.2 Description
  • 5.5 Properties of service-access-points
  • 5.6 Data Units
    • 5.6.1 Definitions
    • 5.6.2 Description
  • 5.7 Elements of layer operation
    • 5.7.1 Definitions
    • 5.7.2 Protocol selection
    • 5.7.3 Properties of connections
    • 5.7.4 Connection establishment and release
    • 5.7.5 Multiplexing and splitting
    • 5.7.6 Transfer of data
    • 5.7.7 Error functions
  • 5.8 Routing
  • 5.9 Management aspects of OSI
    • 5.9.1 Definitions
    • 5.9.2 Introduction
    • 5.9.3 Categories of management activities
    • 5.9.4 Principles for positioning management functions
• 6 Introduction
  • 6.1 Specific layers
  • 6.2 The principles used to determine the seven layers in the Reference Model
  • 6.3 Layer descriptions
• 7 Detailed description of the resulting OSI architecture
  • 7.1 Application layer
    • 7.1.1 Definitions
    • 7.1.2 Purpose
    • 7.1.3 Services provided to applications-processes
    • 7.1.4 Functions within the application layer
  • 7.2 Presentation layer
    • 7.2.1 Definitions
    • 7.2.2 Purpose
    • 7.2.3 Services provided to the application layer
    • 7.2.4 Functions within the presentation layer
  • 7.3 Session layer
    • 7.3.1 Definitions
    • 7.3.2 Purpose
    • 7.3.3 Services provided to the presentation layer
    • 7.3.4 Functions within the session layer
  • 7.4 The transport layer
    • 7.4.1 Definitions
    • 7.4.2 Purpose
    • 7.4.3 Services provided to the session layer
    • 7.4.4 Functions within the transport layer
  • 7.5 Network layer
    • 7.5.1 Definitions
    • 7.5.2 Purpose
    • 7.5.3 Services provided to the transport layer
    • 7.5.4 Functions within the network layer
  • 7.6 Data link layer
    • 7.6.1 Definitions
    • 7.6.2 Purpose
    • 7.6.3 Services provided to the network layer
    • 7.6.4 Functions within the data link layer
  • 7.7 Physical layer
    • 7.7.1 Definitions
    • 7.7.2 Purpose
    • 7.7.3 Services provided to the data link layer
    • 7.7.4 Functions within the physical layer
• ANNEX A – Brief explanation of how the layers were chosen
• ANNEX B – Alphabetical index to definitions