VLAN Configuration and Inter-VLAN Routing Tips

1. Understand VLAN Tags and Standards - Be well-versed in 802.1Q tagging, including the structure of VLAN frames. Understand the implications of changes in VLAN configurations on network traffic.

2. Demonstrate Practical Knowledge - Bring a laptop with simulator software (like GNS3 or Cisco Packet Tracer) and be prepared to demonstrate a VLAN configuration live during the interview, showcasing hands-on experience.

3. Articulate the Importance of VTP - Explain how the VLAN Trunking Protocol (VTP) works and its advantages in managing VLANs across multiple switches, including scenarios where VTP could introduce vulnerabilities if not managed correctly.

4. Discuss Security Implications - Be prepared to discuss how to secure VLANs using private VLANs (PVLANs) and the role of Access Control Lists (ACLs) in controlling VLAN traffic.

5. Explain Inter-VLAN Routing Options - Differentiate between router-on-a-stick, multilayer switches, and software-defined networking (SDN) solutions for inter-VLAN routing. Be clear about the use cases for each method.

6. Have Real-World Scenarios Ready - Prepare to discuss case studies or projects where you successfully implemented VLANs in a business context and the outcomes that benefited the organization.

7. Know About Troubleshooting Tools - Be familiar with tools and commands used for troubleshooting VLAN-related issues, such as `show vlan`, `show ip route`, and `ping`, and how to interpret their outputs.

8. Understand Layer 2 and Layer 3 Functions - Explain the differences between Layer 2 (switching) and Layer 3 (routing) and how VLANs operate at these layers, emphasizing your understanding of the OSI model.

9. Discuss Scaling and Best Practices - Talk about best practices for scaling VLANs, such as segmenting traffic, avoiding broadcast storms, and keeping VLANs organized, especially in larger enterprise networks.

10. Stay Updated with Technologies - Mention emerging technologies related to VLANs, like Network Virtualization and VXLAN, and express your commitment to continuous learning in the field.