Priority and ToS/DSCP Marking

After packets are classified, they are assigned a final User Priority (UP) value. The Priority and ToS/DSCP Marking bits to be applied to the packet is taken from the CoS (Class of Service) and if not set, the received value (ToS/DSCP) is used. ToS/DSCP Marking rewrites the Layer 3 Type of Service (ToS) byte.