Configuring VLANs and Inter‑VLAN Routing with a Layer 3 Switch

Scenario: a company with technical and sales departments in separate VLANs needs inter‑VLAN communication via a layer‑3 switch.

PC configurations: PC0 (192.168.1.2/24 GW 192.168.1.1), PC1 (192.168.2.2/24 GW 192.168.2.1), PC2 (192.168.1.3/24 GW 192.168.1.1). Tests: ping between PCs.

Layer‑2 switch setup: create VLAN 2 and VLAN 3, assign ports fa0/2 to VLAN 2, fa0/3 to VLAN 3, set fa0/1 as trunk, then display VLAN table.

Layer‑3 switch configuration (commands):

Switch>en

Switch#conf t

Switch(config)#vlan 2 // new VLAN 2

Switch(config)#vlan 3 // new VLAN 3

Switch(config)#int fa 0/1 // trunk port

Switch(config-if)#switchport trunk encapsulation dot1q

Switch(config-if)#switchport mode trunk

Switch(config)#int fa 0/2 // access port for VLAN 2

Switch(config-if)#switchport access vlan 2

Switch(config)#int fa 0/3 // access port for VLAN 3

Switch(config-if)#switchport access vlan 3

Switch(config)#interface vlan 2

Switch(config-if)#ip address 192.168.1.1 255.255.255.0

Switch(config-if)#no shutdown

Switch(config)#interface vlan 3

Switch(config-if)#ip address 192.168.2.1 255.255.255.0

Switch(config-if)#no shutdown

Switch#show ip route

Switch#show vlan

Verification: ping tests from PC0 to PC2 and PC1 confirm successful inter‑VLAN routing.

Note: The layer‑3 switch performs routing between VLANs using SVI (Switched Virtual Interface) with assigned IP addresses, enabling devices in different VLANs to communicate.