Two Company switches are connected via a trunk link. In this network， the original frame is  encapsulated and an additional header is added before the frame is carried over a trunk link. At  the receiving end， the header is removed and the frame is forwarded to the assigned VLAN. 
This  describes which technology？（）

When the Catalyst switch R1 is enabled to use VTP， 
which information does it advertise on its  trunk ports？（）