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？（）

• A、 DISL
• B、 ISL
• C、 DTP
• D、 IEEE 802.1Q
• E、 MPLS
• F、 None of the other alternatives apply