30 Second Summary
Demonstrates practical networking knowledge — specifically how enterprise networks are segmented to separate traffic types. Network segmentation affects how users connect, why some devices cannot reach others, and how VoIP quality is maintained. Expected knowledge at L2 and above.
VLAN Architecture
| VLAN | Name | Subnet | Purpose |
|---|---|---|---|
| 10 | Data | 192.168.10.0/24 | User PCs and laptops |
| 20 | VoIP | 192.168.20.0/24 | IP phones — isolated for QoS |
| 30 | Servers | 192.168.30.0/24 | File/print servers |
| 40 | Guest | 192.168.40.0/24 | Internet only — ACL isolated |
Step-by-Step Breakdown
1
Plan Topology and IP Addressing
›
Mapped out the full network design before opening Packet Tracer: identified VLAN count, assigned /24 subnets, planned inter-VLAN routing at the Layer 3 switch, decided Guest VLAN would be internet-only via ACL.
2
Build Physical Topology in Packet Tracer
›
- 1x Layer 3 switch (Cisco 3560) as core — handles inter-VLAN routing
- 4x Layer 2 access switches — one per zone, connected via trunk links
- 1x Router for upstream internet connectivity
- End devices: PCs, IP phones, laptops, and server in each VLAN
3
Configure VLANs and Assign Ports
›
- Created VLANs on all switches:
vlan 100,name desktops,vlan 200,name laptops - Access ports:
switchport mode access,switchport access vlan 100 - Trunk ports:
switchport mode trunk - Voice VLAN:
switchport voice vlan 20 - Verified:
show vlan briefandshow interfaces trunk
4
Enable Inter-VLAN Routing on L3 Switch
›
- Created SVIs for each VLAN as the default gateway
- Example:
interface vlan 10→ip address 192.168.10.1 255.255.255.0 - Enabled IP routing:
ip routing - Default route to router:
ip route 0.0.0.0 0.0.0.0 [router IP]
5
Configure Per-VLAN DHCP and Apply Guest ACL
›
- Set up DHCP pools on L3 switch for each VLAN — excluded gateway IPs
- ACL applied inbound on VLAN 40 SVI: denies traffic to internal subnets, permits internet
- Test: Guest PC → Data VLAN = denied. Guest PC → 8.8.8.8 = permitted.
Proof of Work
Click any image to expand.
Packet Tracer — Network Topology
Switch CLI — VLAN 100 & 200 Creation
show vlan — VLANs Active with Port Assignments
show vlan — Full Port Assignment Verification
