Network+ OSI Model and Data Encapsulation Flashcards

Which of the following correctly lists the OSI layers from Layer 7 down to Layer 1?

Answer: Application, Presentation, Session, Transport, Network, Data Link, Physical

The OSI model layers from 7 to 1 are: Application, Presentation, Session, Transport, Network, Data Link, Physical.

HTTP and FTP are examples of protocols operating at which OSI layer?

Answer: Application layer

HTTP and FTP are Application layer (Layer 7) protocols that provide services directly to end-user applications.

When a host encapsulates data at the Network layer, what information is added to the packet header?

Answer: Source and destination IP addresses

The Network layer adds source and destination IP addresses to the packet header to enable logical addressing and routing.

Which OSI layer is responsible for logical topology and media access control?

Answer: Data Link layer

The Data Link layer defines logical topology and controls how devices share the physical medium through media access control (MAC).

A VPN concentrator encrypts data before it is sent across the internet. Which OSI layer is primarily associated with this encryption function?

Answer: Presentation layer

Encryption and decryption are Presentation layer (Layer 6) functions, though in practice VPN encryption may also be implemented at lower layers.

At which OSI layer does a hub operate?

Answer: Layer 1 — Physical

Hubs operate at Layer 1 (Physical layer), simply repeating electrical signals to all ports without any intelligence or address awareness.

Which term describes the process of adding protocol headers and trailers as data moves down the OSI stack from the Application layer to the Physical layer?

Answer: Encapsulation

Encapsulation is the process of wrapping data with protocol-specific headers (and sometimes trailers) at each successive OSI layer as it moves toward transmission.