VLAN Trunking Protocol (VTP) version 3 does not require virtual LANs (VLANs) to be in the range from 1 through 1,000. VTP version 3 improves on VTP version 2 by increasing the number of supported VLANs from 1,000 to 4,095, which is the same range specified in the Institute of Electrical and Electronics Engineers (IEEE) 802.1Q standard.

VTP version 3 uses primary servers. VTP version 2 relies on a configuration revision number to determine whether the VLAN configuration should be modified on a switch. By contrast, VTP version 3 uses configuration revision numbers and a primary server system to determine which configurations should be changed and which devices are allowed to implement changes. The intended purpose of the primary server is to mitigate accidental overwrites of the VLAN database. However, because VTP version 2 does not support primary servers, Cisco recommends that VTP version 2 devices that are to be connected to a VTP version 3 network be placed into VTP client mode.

VTP version 3 can use encrypted passwords for authentication. VTP version 2 supports cleartext passwords only.

VTP version 3 is backward compatible with VTP version 2 and can therefore support normal VLANs. When a switch configured with VTP version 3 receives a VTP version 2 advertisement on a port, it sends VTP version 2 messages on that port and VTP version 3 messages on the other ports.

VTP version 3 improves on VTP version 2 by adding support for private VLANs (PVLANs). In addition, VTP version 3 adds support for databases other than VLAN databases, such as Multiple Spanning Tree (MST) databases.