▪ Frame tagging is the process of a

▪ Frame tagging is the process of adding a VLAN identification header
to the frame.
▪ It is used to properly transmit multiple VLAN frames through a trunk
link.
▪ Switches tag frames to identify the VLAN to that they belong.
Different tagging protocols exist; IEEE 802.1Q is a vey popular
example.
▪ The protocol defines the structure of the tagging header added to the
frame.
▪ Switches add VLAN tags to the frames before placing them into trunk
links and remove the tags before forwarding frames through
nontrunk ports.
▪ When properly tagged, the frames can transverse any number of
switches via trunk links and still be forwarded within the correct
VLAN at the destination.