TCP/IP Model Layers

  • Application
  • Transport
  • Network
  • Data Link
  • Physical

Application Layer

The application level layer controls services for the applications themselves. Including:

HTTP

  • HTTP provides interface between software and the network.
  • HTTP traffic
    • PC > | HTTP Header | GET home.html | > Web server
    • Web server > | HTTP Header | OK | Data | home.html | > PC

Key terms

Term: Same layer interaction on different computers. Defenition: Communicate with the same layer on another computer.

Term: Adjacent layer interaction on the same computer Definition: One lower layer provides a service to the layer just above. The higher layer makes the next lower layer perform a function.

Note: Wireless protocols function on Layer 2.

Encapsulation

  • TCP/ Data (segment)
  • IP/ Data (Packet)
  • LH/ Data/ LT (Frame) (Link header & Link Trailer)

Protocol Data Units

  • L7H/ Data (L7PDU)
  • L6H/ Data (L6PDU)
  • L5H/ Data (L5PDU)
  • L4H/ Data (L4PDU)
  • L3H/ Data (L3PDU)
  • L2H/ Data/ L2T (L2PDU)