CCNA Routing and Switching (legacy) — Question 141

Which two correctly describe steps in the OSI data encapsulation process? (Choose two.)

Answer options

• A. The presentation layer translates bits into voltages for transmission across the physical link.
• B. The data link layer adds physical source and destination addresses and an FCS to the segment.
• C. Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
• D. Packets are created when the network layer encapsulates a frame with source and destination host addresses and protocol-related control information.
• E. The transport layer divides a data stream into segments and may add reliability and flow control information.

Correct answer: C, E

Explanation

The correct answers, C and E, highlight the functions of the network and transport layers in the OSI model. C correctly states that packets are created when Layer 3 addresses are added to a segment, while E explains how the transport layer segments a data stream and may incorporate reliability features. Options A, B, and D incorrectly describe the roles of the layers, particularly in how packets and frames are defined and created.