How many versions of VTP are there?

VLAN Trunking Protocol (VTP) indeed has three main versions: VTP Version 1, VTP Version 2, and VTP Version 3.

VTP Version 1 is the original version, which provides basic functionalities for managing VLANs across a network. It introduces the concept of a VTP domain and allows for the propagation of VLAN information across the trunk links between switches.

VTP Version 2 builds upon the features of Version 1 by adding support for token ring VLANs, as well as the ability to send VTP advertisements over unidirectional links. This version also includes the capability to handle VLANs with different characteristics more effectively.

VTP Version 3 is the most advanced iteration and introduces features such as enhanced security measures and improved VLAN configuration management. It allows for greater flexibility by supporting extended VLANs (from 1025 to 4096) and includes mechanisms for better handling of VLAN information, ensuring that switches do not overwrite or mismanage VLAN data.

Understanding the distinctions between these versions is crucial for network administration, as choosing the correct VTP version can significantly impact VLAN management and network performance.