Key Concept #3 Layering Internet design is strongly partitioned into layers Each layer relies on services provided by next layer below and provides services to layer above it Analogy Code You write Consider structure of an application you've written Run-Time Library and the“ services”each System Calls layer relies on/ provides Device Drivers Fully isolated Voltage Levels/ from user Magnetic Domains programsKey Concept #3: Layering • Internet design is strongly partitioned into layers – Each layer relies on services provided by next layer below … – … and provides services to layer above it • Analogy: – Consider structure of an application you’ve written and the “services” each layer relies on / provides System Calls Device Drivers VoltageLevels / Magnetic Domains 10 } Fully isolated from user programs CodeYou Write Run-Time Library