1.6 Layering Principle

Layering

• E.x. flights: google flights --> airlines (abstract the details of each airlines)

• E.x. postal service

  • Mail

  • Postal service

  • Medias

  • Mailman

• Can improve each layer independently over time (the interface is the same)

• E.x. computer system

  • Breakdown into functional components, each with well-defined roles

  • Clear separations of concerns

  • Each can be improved, updated over time

E.x. computer system

• Break the layers boundary only if needed

Reasons for layering

• p2p: specific to layered communication systems

  • 4-layer: each layer communicate with its peer on the another system, using the delivery service provided by the layers below