ISO-OSI Network Layers

Objectives:

Networking Technology students will be required to know the layers, topics, and methods of this network model. It is recommended that you be able to create most of this chart from memory.

  • 7. Application - This layer has 3 topics and is associated with Messages
    • Network Services
      • File services
      • Print services
      • Message services
      • Application services
      • Database services
    • Service Advertisement - how services become known
    • Service Use - how services are obtained
  • 6. Presentation - This layer has 2 topics and is associated with Packets
    • Translation - bit translation, byte translation, character code translation, file translation
    • Encryption - cipher, private key or public key
  • 5. Session - This layer has 2 topics and is associated with Packets
    • Dialog Control - simplex, half-duplex and duplex
    • Session Administration - connection establishment, data transfer and connection release
  • 4. Transport - This layer has 4 topics and is associated with Segments
    • Address/name Resolution
    • Addressing
    • Segment Development - breaking large messages into segments, combining small messages into segments
    • Connection Services
  • 3. Network - This layer has 6 topics and is associated with Datagrams
    • Addressing - network addresses. There are two methods:
      • Logical Network
      • Service
    • Switching - route creation for packets, messages and circuits. There are three methods:
      • Packet switching
      • Message switching
      • Circuit switching
    • Route Discovery - finding a route. There are two methods:
      • Distance vector
      • Link-state
    • Route Selection - choosing a route. There are two methods:
      • Static
      • Dynamic
    • Connection Services - flow control, error control and packet sequence control. There are three methods:
      • Network-layer flow control
      • Error control
      • Packet sequence control
    • Gateway Services - There is one method: Network layer translation.
  • 2. Data-Link - This layer has 2 sub-layers and 5 topics, and is associated with Frames
    • MAC sublayer
      • Logical Topology - 2 Methods
        • Bus
        • Ring
      • Media Access - 3 Methods
        • Contention
        • Token Passing
        • Polling
      • Addressing - 1 Method
        • Physical Device Address
    • LLC sublayer
      • Transmission Synchronization - 3 Methods
        • Synchronous
        • Asynchronous
        • Isochronous
      • Connection Services - 3 Methods
        • Unacknowledged Connectionless
        • Connection Oriented
        • Acknowledged Connectionless
  • 1. Physical - This layer has 7 topics and is associated with Bits
    • Connection Type - 2 Methods:
      • Point-to-Point
      • Multipoint
    • Physical Topology - 5 Methods
      • Bus
      • Ring
      • Star
      • Mesh
      • Cellular
    • Digital Signaling - 2 Methods
      • Current State
      • State Transition
    • Analog Signaling - 2 Methods
      • Current State
      • State Transition
    • Bit Synchronization - 2 Methods
      • Synchronous
      • Asynchronous
    • Bandwidth Usage - 2 Methods
      • Baseband
      • Broadband
    • Multiplexing - 3 Methods
      • Frequency Division
      • Time Division
      • Statistical Time Division