Embodiments presented herein describe techniques for isolating multicast and broadcast frames to a traffic class that is separate from a traffic class used for unicast frames. According to one embodiment, a network switch receives an incoming Ethernet virtual local area network (VLAN)-tagged frame. The switch evaluates priority bits of the VLAN tag of the frame. The switch also determines a type of frame (e.g., whether the frame is unicast, broadcast, multicast, or flood). Based on the priority field values and the type of the frame, the switch identifies a mapping of the frame to a particular traffic class. The network switch assigns the frame to the traffic class.