Examkin

Question

Difficulty: MediumOSI Model Layers and Functions

During a network security configuration task, a technician implements packet-filtering rules on a gateway router to inspect incoming traffic based on source and destination IP addresses and forward traffic between separate subnets. At which OSI model layer does this IP addressing and routing function take place, and what is the associated Protocol Data Unit (PDU)?

  1. Network Layer (Layer 3) processing packetsAnswer
  2. B
    Data Link Layer (Layer 2) processing frames
  3. C
    Transport Layer (Layer 4) processing segments
  4. D
    Application Layer (Layer 7) processing data

Answer

Network Layer (Layer 3) processing packets
The Network Layer (Layer 3) is responsible for logical addressing (IPv4/IPv6), packet forwarding, and path selection (routing) between different networks. The Protocol Data Unit (PDU) created and processed at Layer 3 is the packet.

Step-by-Step Solution

1
Identify the primary function described in the scenario.
The scenario describes examining source/destination IP addresses and routing traffic between different subnets.
Logical addressing (IP addresses) and path determination (routing) across subnets are core responsibilities of the Network Layer.
2
Determine the Protocol Data Unit (PDU) at this layer.
The PDU at the Network Layer is the packet.
Data encapsulated with Layer 3 headers containing source and destination IP addresses is defined as a packet.

Key Concept

OSI Network Layer Functions and PDUs
Rate this question

Topics

OSI Model Layers and Functions

More questions from this topic