Certainly! **Router-on-a-Stick** is a technique used to enable inter-VLAN routing using a single physical link between a router and a switch. Let's walk through the steps to configure it:

1. **Create VLANs on the Switch (S1)**:
    - Create VLAN 10 and VLAN 30 on S1:
        ```
        S1(config)# vlan 10
        S1(config-vlan)# name LAN10
        S1(config-vlan)# exit
        S1(config)# vlan 30
        S1(config-vlan)# name LAN30
        S1(config-vlan)# exit
        ```

2. **Assign VLANs to Ports**:
    - Configure interfaces F0/6 and F0/11 as access ports and assign VLANs:
        ```
        S1(config)# interface f0/11
        S1(config-if)# switchport mode access
        S1(config-if)# switchport access vlan 10
        S1(config-if)# interface f0/6
        S1(config-if)# switchport mode access
        S1(config-if)# switchport access vlan 30
        ```

3. **Test Connectivity**:
    - Verify that PC1 and PC3 can ping each other. If not, remember that they are on different IP networks and require a router or Layer 3 switch for communication.

4. **Configure Subinterfaces on R1 (Router)**:
    - Create subinterfaces on R1 using 802.1Q encapsulation:
        ```
        R1(config)# interface g0/0.10
        R1(config-subif)# encapsulation dot1Q 10
        R1(config-subif)# ip address 172.17.10.1 255.255.255.0
        R1(config-subif)# interface g0/0.30
        R1(config-subif)# encapsulation dot1Q 30
        R1(config-subif)# ip address 172.17.30.1 255.255.255.0
        ```

5. **Verify Configuration**:
    - Use the `show ip interface brief` command to verify subinterface configuration.

Remember that router-on-a-stick allows routing between VLANs by logically dividing the router interface into subinterfaces, each associated with a specific VLAN. Trunk links between switches and the router are essential for forwarding traffic within and between VLANs. 🌐🔗

![Router-on-a-Stick Topology](https://www.ciscopress.com/articles/article.asp?p=3089357&seqNum=5)