WEEK 5: Lecture Activity - M199205zn/Datacomm-CS3 GitHub Wiki

Activity: Understanding the OSI Model and Its Layers

Objective:

  • To understand the seven layers of the OSI model.
  • To identify the functions and protocols associated with each layer.
  • To analyze real-world scenarios and determine which OSI layer is involved.

1: Matching OSI Layers with Their Functions

Instructions: Match each OSI layer with its corresponding function. Write the correct layer next to each function.

Function OSI Layer
Translates data between different network formats ________
Establishes, maintains, and terminates communication sessions ________
Converts signals into bits for transmission over the network medium ________
Routes packets between different networks ________
Ensures reliable data transfer with error detection and correction ________
Handles logical addressing (IP addresses) ________
Enables user applications to access the network services ________

2: Identifying OSI Layers in Real-World Scenarios

Instructions: Read each scenario below and identify the OSI layer primarily involved. Explain your reasoning.

  1. A user uploads a file to a cloud server using an FTP client.

    • OSI Layer: __________
    • Explanation:

  2. A router forwards packets from one network to another based on IP addresses.

    • OSI Layer: __________
    • Explanation:

  3. A switch forwards data frames based on MAC addresses.

    • OSI Layer: __________
    • Explanation:

  4. A user types a website URL, and the browser resolves it to an IP address using DNS.

    • OSI Layer: __________
    • Explanation:

  5. A video call suffers from delays due to network congestion, affecting the smooth transmission of voice and video.

    • OSI Layer: __________
    • Explanation:

3: OSI Model Troubleshooting Challenge

Scenario: A user is experiencing issues when trying to access a website. Identify which OSI layer could be responsible for the problem and explain why.

  1. Problem: The website's domain name is not resolving.

    • Possible OSI Layer: __________
    • Reason:

  2. Problem: The computer can’t connect to the network because the network cable is unplugged.

    • Possible OSI Layer: __________
    • Reason:

  3. Problem: The webpage loads very slowly due to packet loss and retransmissions.

    • Possible OSI Layer: __________
    • Reason:

4: Diagram Drawing

Instructions:

  • Draw a diagram of the OSI model, labeling each layer.
  • Provide an example of a real-world networking device or protocol that operates at each layer.

Expected Output:

  • Completed OSI layer function matching.
  • Correct OSI layer identification for each real-world scenario.
  • Troubleshooting explanations linking network problems to OSI layers.
  • A well-labeled OSI model diagram with real-world examples.
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