FR queuing

Besides FR PVC queues, FR interfaces also have interface queues. With FRTS disabled, only FR interface queues take effect, and the predefined FR PVC queues take effect only in the case that FRTS is enabled.

The relationship between PVC queues and interface queues is shown in Figure 46.

The following queuing mechanisms are available on FR interfaces:

• FIFO

• PQ

• CQ

• WFQ

• CBQ

• RTPQ

• PVC PQ

Of these queuing mechanisms, FIFO, PQ, CQ, WFQ, CBQ, and RTPQ are universal queuing mechanisms. For more information, see "Configuring congestion management."

PVC PQ can only be applied on FR interfaces. PVC priority queues include the following types: top, middle, normal, and bottom, in the descending priority order. The packets from a certain PVC must be assigned to one PVC priority queue, and the packets from PVCs are assigned to PVC priority queues on the interface as configured. PVC PQ dequeues and sends packets in the high-priority queue and then packets in the low-priority queue.

FR PVC queuing mechanisms include FIFO, PQ, CQ, WFQ, CBQ, and RTPQ. Only RTPQ can coexist with another queuing mechanism.

With FRTS enabled on an interface, only FIFO, RTPQ, or PVC PQ is available on the interface.