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OSI and TCP/IP Models Flashcards

7 cards from real Cisco CCNA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 OSI and TCP/IP Models flashcards as text

  1. A network engineer needs to troubleshoot why two hosts can ping each other but cannot establish a Telnet session. Which OSI layer should be investigated first?

    Answer: Layer 4 - Transport

    Ping operates at Layer 3, so if ping works, Layers 1-3 are functional; Telnet failures point to Layer 4 (TCP port 23) or above.

  2. Which TCP/IP model layer is responsible for logical addressing and routing between networks?

    Answer: Internet

    The Internet layer of the TCP/IP model handles IP addressing and routing, equivalent to the OSI Network layer.

  3. What is the term for the data unit at the OSI Data Link layer?

    Answer: Frame

    The Data Link layer (Layer 2) encapsulates data into frames, which include MAC addressing and error detection (FCS).

  4. Which OSI layer converts data between formats such as encryption, compression, and character encoding?

    Answer: Presentation (Layer 6)

    The Presentation layer (Layer 6) handles data translation, encryption/decryption, and compression between the application and network.

  5. In which scenario does the OSI Session layer play a critical role?

    Answer: Managing dialog control between two applications in a video conference

    The Session layer (Layer 5) establishes, manages, and terminates communication sessions, including dialog control for applications like video conferencing.

  6. A router receives a packet destined for a remote network. At which OSI layer does it make the forwarding decision?

    Answer: Layer 3

    Routers operate at Layer 3 (Network) and use the destination IP address in the packet header to make forwarding decisions.

  7. Which statement correctly describes encapsulation in the OSI model?

    Answer: Each layer adds its own header (and sometimes trailer) to data received from the layer above

    During encapsulation, each OSI layer on the sending host adds its own header (and trailer at Layer 2) to the data passed down from the layer above.