(So we can do WAN PPP/CHAP later: To cover other CCNA objectives)
We’re doing this now because the default router often doesn’t have Serial interfaces until we add a module.
3.1 Do this on R1 first
- Click R1
- Go to the Physical tab
- Click the power switch (turn it OFF)
- In the left “Modules” list, find HWIC-2T
- If you don’t see HWIC-2T, look for WIC-2T (Packet Tracer versions vary)
- Drag HWIC-2T / WIC-2T into an empty slot on the router
- Turn the router ON again
✅ Result you must see: R1 now has Serial0/0/0 (and usually Serial0/0/1 too)
3.2 Repeat the same on R2
Same exact steps:
- Physical tab → power OFF → add HWIC-2T/WIC-2T → power ON
✅ Result: R2 now has Serial0/0/0
3.3 Quick check (to confirm Step 3 is done)
Click R1 > Config tab (or CLI later) and look for interfaces:
- You should see Serial0/0/0
Do the same for R2.
Step 3 (continued) — Connect the TWO routers that have serial modules
Step 3 (continued) — Connect the TWO routers that have serial modules
First: identify which routers have Serial0/0/0
- Click R1 → Config
- Check if you see Serial0/0/0
- Do the same for R1 and R3
👉 You must find TWO routers that both have Serial0/0/0
Step 3A — Connect the serial link (ONLY this)
Once you identify the two routers with serial ports:
- Click Connections (⚡ icon)
- Choose Serial DCE cable (red cable)
- Click Router A → Serial0/0/0
- Click Router B → Serial0/0/0
That’s it. No config. No IPs.
What you should see
- A red serial cable between the two routers
- Link may stay red/down → this is NORMAL
(serial links stay down until clock rate + config)
Very important
❌ Do NOT connect serial to a switch
❌ Do NOT worry if it’s red
✅ Just make sure Serial0/0/0 ↔ Serial0/0/0
❓ Why did we use serial between HO-R1 and BR-R2?
Short answer
👉 Because CCNA wants you to understand WAN concepts, not just Ethernet.
Longer (but simple) explanation
In the real world today:
- Companies usually use:
- Fibre
- MPLS
- Metro Ethernet
- Serial links are rare now
But for learning, serial links are still used because they teach more concepts.
🎯 What serial teaches that Ethernet does NOT
By using serial, you learned:
1️⃣ WAN vs LAN difference
2️⃣ DCE vs DTE
3️⃣ Clock rate
4️⃣ Point-to-point links
5️⃣ /30 subnetting
6️⃣ Why WAN links behave differently
These are explicit CCNA exam topics.
If we used fibre/Ethernet:
- You would skip DCE/DTE
- Skip clocking
- Skip key WAN theory
That’s why serial is used in labs.
