If the network path between the two endpoints is QoS aware, SonicOS can DSCP tag:
SonicOS can map 802.1p tags created on the internal networks to DSCP tags so that they can safely traverse the transit network. When the packets are received on the other side, the receiving SonicWall appliance can translate the DSCP tags back to 802.1p tags for interpretation and honoring by that internal network.