1.7 Encapsulation Principle

The result of what happens when you combine layering and packet switching

  • Each packet contains data from multiple layers

  • The principle by which you organize information in packets so that you can maintain layers, yet let them share the contents of packets

  • Each protocol layer has some headers, payload, footers

    • E.x. IP packet header: source addr, dest addr

    • To send TCP segment with IP, make the TCP format the payload of the IP packet (IP packet "encapsulates" the TCP segment)


  • Browsing a web using a computer connected through WiFi

  • Generates an HTTP GET request

    • Payload of a TCP segment

    • Payload of IP packet

    • Payload of WiFi frame

  • Both correct

Encapsulation Flexibility

  • Able to layer recursively

  • Transport layer security (TLS)

  • Allows you to access private, protected network resources inside your office

  • TLS session is inside a TCP stream that terminates at the virtual private network gateway

  • How we take protocol layers and assemble them into packets in a way that's flexible and maintains their separation of concerns

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