Allied Telesis AT 8000/8POE - Manual (Page 143)

AT-S81 Management Software User’s Guide
Section I: Using the Menus Interface 143
Note
The tagged information in a frame is not changed as the frame
traverses the switch. A tagged frame leaves a switch with the same
priority level that it had when it entered.
The default for this parameter is disabled, meaning that the priority
level of tagged frames is determined by the priority level specified in
the frames themselves.