Cisco switches support three VLAN Trunking Protocol (VTP) modes:

1. VTP Server: In this mode, a switch can create, modify, and delete VLANs, and the changes are propagated to other switches in the same VTP domain. The VTP server is the central point of management for the VLAN information in the domain.
2. VTP Client: In this mode, a switch can receive and store VLAN information from the VTP server but cannot create, modify, or delete VLANs. The VTP client relies on the VTP server to manage the VLAN information.
3. VTP Transparent: In this mode, a switch neither participates in the distribution of VLAN information nor modifies its own VLAN configuration. VTP transparent switches simply forward VTP messages to other switches in the network.

The VTP mode is important because it determines the role a switch will play in managing the VLAN information in a network. In a VTP network, it is recommended to have a single VTP server that manages the VLAN information, and all other switches configured as VTP clients or VTP transparent. This helps ensure consistent VLAN information across all switches in the network.