• VLANs provide two major functions:
    • Break up physical switches into virtual “mini switches“
    • Extend the virtual “mini switch” to multiple physical switches
  • VLANs allow your Logical topology to be unconstrained by your Physical topology
  • Access Ports / Untagged Ports – ports which carry traffic for only ONE VLAN
  • Trunk Ports / Tagged Ports – ports which carry traffic for MULTIPLE VLANs
    • All frames traversing a Trunk port must be “tagged”. That way the receiving switch knows what VLAN to associate that traffic to
  • 802.1q – open standard for how to tag Layer 2 frames
  • Native VLAN – The one VLAN which traverses a Trunk/Tagged link without a VLAN tag