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Practical

Practical 3: Network Cabling

Straight-through, crossover, coaxial & phone cables in Packet Tracer

🌐 Introduction to Networks 🛠️ Packet Tracer 👤 Reza Farashahi
In this practical you will explore different types of network cabling and learn when to use straight-through versus crossover cables. You will build a network topology, connect devices with the correct cable types, and label every connection.

🎯 Learning Objectives

📦 Step 1 — Create a New File

Open Cisco Packet Tracer and create a new file.

🖥️ Step 2 — Add Network Devices

Add and label the following devices:

  1. 2 PCs (PC-PT) — label them "Laptop Computer" and "Desktop Computer"
  2. 1 Printer (Printer-PT) — label "Network Printer"
  3. 1 Server (Server-PT) — label "Network Attached Storage (NAS) Server"
  4. 2 Switches (2960-24TT) — label "Switch 1" and "Switch 2"
  5. 1 Router (2811) — label "Router"
  6. 1 Wireless Router (HomeRouter-PT-AC) — label "Wireless Router 1 (SOHO)"
  7. 1 Cable Modem (Cable-Modem-PT) — label "Cable Modem"
  8. 1 DSL Modem (DSL-Modem-PT) — label "DSL Modem"
  9. 2 Cloud devices (Cloud-PT) — label "Cable ISP" and "DSL ISP"
Tip: Right-click each device and choose "Edit Device Label" to rename it.

📐 Step 3 — Arrange Devices

Position the devices logically:

🔌 Step 4 — Connect Devices

Use the Connections panel to select the correct cable for each link.

4.1 — Devices to Switch 1 (Straight-Through)

  1. Select Copper Straight-Through.
  2. Laptop Computer (FastEthernet) → Switch 1
  3. Desktop Computer (FastEthernet) → Switch 1
  4. Network Printer (FastEthernet) → Switch 1
  5. NAS Server (FastEthernet) → Switch 1

Label these connections "Straight Through Cables".

4.2 — Switch 1 to Router (Straight-Through)

  1. Switch 1 (available port) → Router (GigabitEthernet0/0)

Label: "Straight Through".

4.3 — PC 1 to Switch 2 (Straight-Through)

  1. PC 1 (FastEthernet) → Switch 2

Label: "Straight Through".

4.4 — Switch 2 to Wireless Router (Crossover)

  1. Select Copper Crossover.
  2. Switch 2 (available port) → Wireless Router (GigabitEthernet1)

Label: "Crossover".

4.5 — Wireless Router to Cable Modem (Straight-Through)

  1. Wireless Router (Internet port) → Cable Modem (Port1)

Label: "Straight Through".

4.6 — Cable Modem to Cable ISP (Coaxial)

  1. Select Coaxial.
  2. Cable Modem (coaxial port) → Cable ISP

Label: "Coaxial".

4.7 — DSL Modem to DSL ISP (Phone Line)

  1. Select Phone cable (RJ-11).
  2. DSL Modem (phone port) → DSL ISP

Label: "Phone Line (RJ-11)".

🏷️ Step 5 — Label All Connections

Right-click each cable and add labels using Place Note or the label tool. Make sure every link is clearly identified with its cable type.

✅ Step 6 — Verify Your Work

Review your topology and confirm:

🔩 Step 7 — Add a Second Interface to the Router

In Lab 1 you added an extra NIC to a server. Now you will add a serial module to the Router (2811) so it can connect to the DSL Modem side of the network.

  1. Click on the Router to open its configuration window.
  2. Go to the Physical tab.
  3. Power off the router by clicking the power button.
  4. In the left module list, find WIC-1ENET (single Ethernet WAN interface card).
  5. Drag the module to an empty WIC slot on the router.
  6. Power the router back on.
  7. Close the configuration window.

Connect the New Interface

  1. Select Copper Straight-Through.
  2. Connect Router (Ethernet0/0/0 — the new port) → DSL Modem (Ethernet port).
  3. Label this connection “Straight Through”.
Recall from Lab 1: You must always power off a device before adding hardware modules, then power it back on — just like when you added a second NIC to the servers.

⭐ Step 8 — Extend with a Star Sub-Network

In Lab 1 you created a standalone star topology. Now you will add a small star network that extends your existing topology.

  1. Add 2 more PCs (PC-PT) to the workspace. Label them “PC 2” and “PC 3”.
  2. Add 1 Laptop — label it “Laptop 2”.
  3. Position all three devices around Switch 2, forming a star pattern.
  4. Using Copper Straight-Through, connect:
    • PC 2 (FastEthernet0) → Switch 2
    • PC 3 (FastEthernet0) → Switch 2
    • Laptop 2 (FastEthernet0) → Switch 2
  5. Label the area “Star Sub-Network” using Place Note.
Compare with Lab 1: In Lab 1, Switch 2 was the centre of an isolated star. Here it is part of a larger network — data from these new devices can travel through the Wireless Router, Cable Modem, and out to the Internet.

📶 Step 9 — Add & Configure a Wireless Device

In Lab 2 you verified wireless connections by checking for dotted lines. Now you will add a wireless device and configure its connection settings.

Add a Tablet

  1. From End Devices, add a Tablet to the workspace and label it “Tablet”.

Configure the Wireless Router SSID

  1. Click on Wireless Router 1 (SOHO) to open its settings.
  2. Go to the GUI tab (the router’s web interface).
  3. Navigate to Wireless → Basic Wireless Settings.
  4. Set the SSID to “HomeLAN”.
  5. Click Save Settings.

Connect the Tablet to Wi-Fi

  1. Click on the Tablet to open its configuration.
  2. Go to the Config tab → Wireless0.
  3. Set the SSID to “HomeLAN” (must match the router).
  4. Close the panel. A dotted line should appear connecting the Tablet to the Wireless Router.
Common mistake: If the Tablet does not connect, double-check that the SSID is typed exactly the same on both the router and the device — it is case-sensitive.

🔍 Step 10 — Test Connectivity with CLI Commands

In Lab 2 you used ipconfig and ping. Now you will use those commands again and also try tracert on a more complex network.

Check IP Addresses

  1. Wait until all link lights turn green.
  2. Click on PC 1 → Desktop tab → Command Prompt.
  3. Run: 
    ipconfig
  4. Note the IPv4 Address (e.g. 192.168.0.x).
  5. Repeat on Laptop Computer and PC 2 to record their IPs.

Ping Across the Network

  1. From PC 1’s Command Prompt, ping Laptop Computer: 
    ping 192.168.0.x
    Replace with the Laptop’s actual IP.
  2. Successful output looks like: 
    Reply from 192.168.0.x: bytes=32 time<1ms TTL=128
  3. Now ping PC 2 (connected to Switch 2) from PC 1. Does it succeed?

Trace the Route

  1. From PC 1’s Command Prompt, run: 
    tracert 192.168.0.x
    Use PC 2’s IP address.
  2. Observe how many hops the packet takes to reach PC 2.
  3. Each line in the output represents a router or Layer 3 device the packet passed through.
New command — tracert: While ping tells you if a device is reachable, tracert shows you the path packets take to get there. This is invaluable for troubleshooting routing issues.
Troubleshooting: If pings fail, verify: (1) cables are correct types, (2) all link lights are green, (3) devices have IP addresses assigned via DHCP or static configuration.

📖 Cable Type Reference

Connection Cable When to Use
PC → Switch Copper Straight-Through Dissimilar devices (end device → network device)
Switch → Router Copper Straight-Through Dissimilar devices (switch → router)
Switch → Switch Copper Crossover Similar devices (switch → switch)
Switch → SOHO Router (switch ports) Copper Crossover Similar devices (switch → switch ports on SOHO router)
Router → Cable/DSL Modem Copper Straight-Through Dissimilar devices (router → modem)
Cable Modem → ISP Coaxial Cable internet service
DSL Modem → ISP Phone Line (RJ-11) DSL internet over telephone line
Auto-MDIX: Modern devices can auto-detect cable type and configure accordingly, making the straight-through vs. crossover distinction less critical in practice — but the theory is still essential to understand.

💭 Reflection Questions

  1. Why do we use a crossover cable between two switches but a straight-through cable between a PC and a switch?
  2. What is the wiring difference between a straight-through cable and a crossover cable?
  3. Why does a cable modem use coaxial while a DSL modem uses a phone line?
  4. When might you still need to know about crossover vs. straight-through despite Auto-MDIX?