Before typing commands, you must understand why VLANs exist in your network.
Right now (current state)
- All HQ PCs are in one broadcast domain
- All traffic is mixed
- No separation between:
- users
- servers
- Wi-Fi
This does not scale and is not secure.
🔹 What VLANs will do for your design
You already planned this (which is excellent):
| VLAN | Purpose | Subnet |
|---|---|---|
| VLAN 10 | HQ Users | 10.10.10.0/24 |
| VLAN 20 | HQ Servers | 10.10.20.0/24 |
| VLAN 30 | HQ Wi-Fi | 10.10.30.0/24 |
VLANs will:
- Split the switch into multiple logical networks
- Reduce broadcasts
- Enable security policies
- Force traffic to go through the router (Layer 3)
This is why inter-VLAN routing exists.
🔹 What changes conceptually (important)
Before VLANs
PCs ─── Switch ─── Router
After VLANs
VLAN 10 ─┐
VLAN 20 ─┼── Switch ──(TRUNK)── Router
VLAN 30 ─┘
- Switch = Layer 2 separation (VLANs)
- Router = Layer 3 routing between VLANs
🔒 CCNA GOLD RULE (remember this)
One VLAN = One subnet = One default gateway
You already built the subnets — now we bind them to VLANs.
