Allied Telesis AT-S39 - Manual (Page 316)

Section III: Web Browser Management
316
The CoS Settings for Port menu is shown in Figure 100.
Figure 100 CoS Setting for Port Menu
6. If you want all tagged and untagged frames received on the port to
go to the low priority queue, select any level from Level 0 to Level 3
from the Priority pull-down menu. (It does not matter which of these
levels you select.) If you want all frames received on the port to go to
the high priority queue, select any level from Level 4 to Level 7.
(Again, it does not matter which level you select.)
7. If you are configuring a tagged port and you want the switch to
ignore the priority tag in the tagged frames entering the port, click
the Override Priority option. If you activate this feature, all tagged
frames will be directed to either the low or high priority queue
specified in Step 6.
Note
The tagged information in a frame is not changed as the switch
forwards a frame. A tagged frame exits the switch with the same
priority level it had when it entered.
The default for this parameter is No, meaning that the priority
level of a tagged frame is determined by the priority level
specified in the frame itself.
8. Click Apply.
Configuration changes are immediately activated on the switch.