Description: The priority for this L2 flow. There are four priority levels: low, medium, high and control. The highest priority class is reserved for router control traffic, which leaves three classes, high, medium, and low for normal data flows. Buffered traffic in higher priority classes is sent ahead of pending traffic in lower priority classes, which allows latency and throughput demands to be maintained for the higher priority traffic. To prevent low priority traffic from waiting indefinitely as higher priority traffic fills the wire, a weighted fair queuing mechanism provides adjustable minimum bandwidth guarantees at each output port, thereby ensuring that some traffic from each priority class always gets through.