Week 13: OSI MODEL ACTIVITIES - M199205zn/Datacomm-CS3 GitHub Wiki

OSI Model – Packet Tracer Laboratory Activity

Title:

Understanding the OSI Model Using Cisco Packet Tracer

Objective:

To simulate and identify the data encapsulation and flow of data across the seven layers of the OSI model using Cisco Packet Tracer.

Materials Needed:

  • Cisco Packet Tracer software
  • Computer or laptop with Packet Tracer installed
  • Pre-created Packet Tracer file (or students can build it from scratch)

Activity Description:

Students will build a simple network and use simulation mode to observe how data is encapsulated and travels through the layers of the OSI model.

Network Topology:

PC0 ---- Switch ---- Router ---- Switch ---- PC1
  • Configure IP addresses on PCs.
  • Use a router to route between two different subnets.
  • Use Ping and HTTP protocols to view data encapsulation.

Step-by-Step Instructions:

Step 1: Create the Topology

  • Place 2 PCs, 2 switches, and 1 router.
  • Connect PC0 to Switch0, PC1 to Switch1.
  • Connect Switch0 to Router (Fa0/0), and Switch1 to Router (Fa0/1).

Step 2: Configure IP Addressing

PC0 (Network A):

  • IP Address: 192.168.10.2
  • Subnet Mask: 255.255.255.0
  • Default Gateway: 192.168.10.1

PC1 (Network B):

  • IP Address: 192.168.20.2
  • Subnet Mask: 255.255.255.0
  • Default Gateway: 192.168.20.1

Router Configuration (CLI):

Router> enable
Router# configure terminal
Router(config)# interface fa0/0
Router(config-if)# ip address 192.168.10.1 255.255.255.0
Router(config-if)# no shutdown
Router(config-if)# exit
Router(config)# interface fa0/1
Router(config-if)# ip address 192.168.20.1 255.255.255.0
Router(config-if)# no shutdown
Router(config-if)# exit
Router(config)# exit
Router# copy running-config startup-config

Step 3: Test Connectivity

  • Go to PC0 → Desktop → Command Prompt → ping 192.168.20.2

Step 4: Use Simulation Mode

  1. Switch to "Simulation Mode."
  2. From PC0, open the web browser and enter http://192.168.20.2
  3. Observe the PDU traveling from PC0 to PC1.
  4. Click on each PDU to examine OSI layer breakdowns:
    • Application (HTTP)
    • Transport (TCP)
    • Network (IP)
    • Data Link (Ethernet)
    • Physical (Frame transmission)

Expected Output:

  • Successful ping between PC0 and PC1.
  • In simulation, each PDU shows OSI layer details.
  • Understanding of how data is encapsulated and decapsulated layer by layer.

Assessment Questions:

  1. What is the role of each OSI layer observed during the HTTP request?
  2. Which layers added headers and trailers?
  3. How did the router handle the packet?
  4. What would happen if the subnet mask was incorrectly configured?
  5. Why is the MAC address changed at each hop?

Extension Activity (Optional):

  • Add a server instead of PC1 and configure HTTP service.
  • Add a DNS server to resolve hostnames to IPs.