During the OSI layer 3 step of the encapsulation process, what is the Protocol Data Unit (PDU) called when the IP stack adds source (sender) and destination (receiver) IP addresses?

The correct answer is C. Packet. In the OSI model encapsulation process, each layer wraps data in its own Protocol Data Unit (PDU). At Layer 3 (Network layer), the IP stack adds source and destination IP addresses to the data - the resulting PDU is called a Packet. At Layer 2 (Data Link), the PDU is a Frame (MAC

Submitted by naveen.iyer· Apr 18, 2026Cybersecurity Foundations

Question

Options

AFrame
BSegment
CPacket
DData

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C
86% (24)
D
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Explanation

In the OSI model encapsulation process, each layer wraps data in its own Protocol Data Unit (PDU). At Layer 3 (Network layer), the IP stack adds source and destination IP addresses to the data - the resulting PDU is called a Packet. At Layer 2 (Data Link), the PDU is a Frame (MAC addresses are added). At Layer 4 (Transport), the PDU is a Segment (for TCP) or Datagram (for UDP). 'Data' refers to the PDU at Layers 5–7 (Application, Presentation, Session). Remembering the PDU names by layer is a fundamental networking concept.

Topics

#OSI Model#TCP/IP Encapsulation#Network Layer#PDU

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