Chapter 5. VLAN Trunking Protocol
Engineers sometimes have a love/hate relationship with VLAN Trunking Protocol (VTP). VTP serves a useful purpose, distributing the configuration of the [no] vlan vlan-id command among switches. As a result, the engineer configures the vlan command on one switch, and all the rest of the switches are automatically configured with that same command.
Unfortunately, the automated update powers of VTP can also be dangerous. For example, an engineer could delete a VLAN on one switch, not realizing that the command actually deleted the VLAN on all switches. And deleting a VLAN impacts a switch’s forwarding logic: Switches do not forward frames for VLANs that are not defined to the switch.
This chapter discusses VTP, ...