HP FlexNetwork NJ5000 User Manual page 416

Figure 441 SP queuing
A typical switch provides eight queues per port. As shown in Figure 441, SP queuing classifies eight
queues on a port into eight classes, numbered 7 to 0 in descending priority order.
SP queuing schedules the eight queues strictly according to the descending order of priority. It sends
packets in the queue with the highest priority first. When the queue with the highest priority is empty,
it sends packets in the queue with the second highest priority, and so on. You can assign
mission-critical packets to the high priority queue to make sure they are always served first and
common service (such as Email) packets to the low priority queues to be transmitted when the high
priority queues are empty.
The disadvantage of SP queuing is that packets in the lower priority queues cannot be transmitted if
the higher priority queues have packets. This might cause lower priority traffic to starve to death.
WRR queuing
WRR queuing schedules all the queues in turn to make sure every queue can be served for a certain
time, as shown in Figure 442.
Figure 442 WRR queuing
A typical switch provides eight output queues per port. WRR assigns each queue a weight value
(represented by w7, w6, w5, w4, w3, w2, w1, or w0) to decide the proportion of resources assigned
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