When we create VLANs, how does the switch know where to send the frame? Even in a small-to-medium sized network, the number of frames going through a switch is high. The switch has a protocol called the Virtual Trunking Protocol (VTP), which tags all the frames that go through its trunk ports with the appropriate VLAN number and name.
VTP is a crucial switching protocol that we must understand, but we will be discussing that in the advanced switch technology chapter. Let's look at a simple example of the process of frame tagging:
All VLANs need to be tagged by VTP to go across the trunk ports. The only one that does not need to be tagged is the native VLAN since it has a PVID, or port VLAN identifier, already in the frame.
But we will discuss that in the advanced switch chapter.
