When the link type of the  ONU  port is  Trunk  , its processing method for downstream messages is  _____  .

When the link type of the  ONU  port is  Trunk  , its processing method for downstream messages is  _____  .
A . only allowed without  Tag  packets to pass through, and the packets add the default  VLAN  of  Tag
B . Only allow the packets with the default  VLAN tag  to pass and remove the  tag
C . for without receipt of the  Tag  message, add the default  VLAN Tag  ; for received with  Tag  packets forwarded directly
D . Only allow  tagged  messages to pass

View Answer

Answer:   D