How the Internet Model Differs from OSI

• Fewer layers

  • Presentation merged into application
  • Session & transport layers merged into end-to-end

• Single connectionless Internet layer

  • simple, least-common-denominator service

• Subnetwork layer deliberately unspecified

  • may be a simple point-to-point link, a complete network with internal routing, or tin cans & string

• Strong end-to-end emphasis

  • Put functions at endpoints whenever possible
  • Keep the network itself as simple as possible

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