There are two kinds of VTP version 3 servers for a certain
database type - the primary server and the secondary server.
When a local device is configured as a server for a certain
database type, it becomes secondary server by default.
Primary server is an operational role under which a
server can initiate or change the VTP configuration of the
database type.
A true(1) value indicates that the local device is the
primary server of the database type in the management
domain. A false(2) value indicates that the local device
is not the primary server, or the database type is unknown
to the local device.