VLANs are now commonplace in campus networks. VLANs give network engineers flexibility in designing and implementing networks. VLANs also enable broadcast containment, security, and geographically disparate communities of interest. However, as with basic LAN switching, problems can occur when VLANs are implemented. This lesson will show some of the more common problems that can occur with VLANs, and it will provide several tools and techniques for troubleshooting.

Students completing this lesson should be able to:

• Utilize a systematic approach to VLAN troubleshooting
• Demonstrate the steps for general troubleshooting in switched networks
• Describe how spanning-tree problems can lead to broadcast storms
• Use show and debug commands to troubleshoot VLANs

Web Links VLAN Tech Notes http://www.cisco.com/en/US/tech/ tk389/tk689/tech_tech_notes_ list.html