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Network Models and Encapsulation

You’ll be able to

Network Models and Encapsulation

Layered models separate responsibilities. Applications create data, transport protocols manage end-to-end delivery, internet protocols route packets between networks, and link technologies move frames on a local medium. Encapsulation adds the addressing and control information each layer needs.

Decision lens

Strong technical decisions connect evidence → mechanism → impact → response. Identify what the evidence shows, explain the system behavior that produced it, state the likely effect on people or data, and choose a response that addresses the cause without creating unnecessary disruption.

Worked example

A browser request crosses Wi-Fi, a router, and an internet service provider before reaching a web server.

  1. 1.The application creates an HTTP request.
  2. 2.TCP provides an ordered connection and IP supplies routable addresses.
  3. 3.Wi-Fi carries a local frame to the first router.
  4. 4.Each router removes the old link frame and forward the IP packet in a new one.
Answer: The application data remains conceptually the same while lower-layer framing changes from link to link.
Checkpoint

Which layer is primarily responsible for routing between networks?

Checkpoint

Which response best demonstrates complete reasoning about layered network communication?

On the exam

For a scenario about layered network communication, identify the decisive evidence before naming a response. A defensible conclusion here is: The application data remains conceptually the same while lower-layer framing changes from link to link.

Answer the 2 checkpoints as you read.

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