The document discusses Virtual Trunking Protocol (VTP). It describes VTP as a Cisco proprietary protocol that exchanges VLAN information across trunk links, allowing network managers to distribute VLAN configurations to all switches in the same domain. The document outlines the key components of VTP, including domains, advertisements, and pruning. It also details the different VTP modes of server, client, and transparent and how they operate. The benefits of using VTP for VLAN management are presented, along with some common VTP configuration issues.