The document describes how to configure Cisco Catalyst 6500 switches in Virtual Switching System (VSS) mode. Key steps include:
1. Configuring the virtual switch domain ID and assigning switch numbers on each switch to group them.
2. Configuring the virtual switch link interface between the switches, which is used to exchange state information.
3. Executing the "switch convert mode virtual" command on each switch to convert them to VSS mode and reboot the system.
This merges the switch configurations, renumbers interfaces, and designates one switch as active and the other as standby.