Advertisement Request

An advertisement request is sent when a switch has rebooted, the domain name has been changed, or the VTP summary revision number is higher than what is locally on the switch. As noted in Example 4-4, the switch is requesting VTP database information from its directly connected neighbor.

VTP: tx vtp request, domain Cisco, start value

VTP join messages prevent the upstream switches from pruning a VLAN on a trunk. The "VLAN Pruning" section later in this chapter will expand the role of this message type.