Decapsulation description

• A. Wrapping data with headers as it travels down the OSI layer
• B. Providing authentication for users
• C. Removing a header or trailer from a lower OSI layer
• D. Fragmenting packets into smaller frames

Answer: (C)

Decapsulation is the process of removing the control information that lower layers added as data moves up the protocol stack. When a frame arrives, the data link layer header and trailer are stripped away first, revealing the IP packet. Then the IP header is removed to expose the transport segment, and so on up the stack. This upward removal of headers/trailers from a lower layer is exactly what decapsulation describes.

The other ideas don’t fit as descriptions of decapsulation: wrapping data with headers as it travels down describes encapsulation, not decapsulation; providing authentication is a security function, not a data-structure handling process; and fragmentation is about breaking data into smaller pieces for transmission, not removing encapsulation.