HP 5830 Series Configuration Manual page 45

SP queuing
SP queuing is designed for mission-critical applications that require preferential service to reduce the
response delay when congestion occurs.
Figure 14 SP queuing
In Figure 14, 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 in the descending order of priority. SP queuing 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 that they are always served first and common service 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
packets exist in the higher priority queues. This may cause lower priority traffic to starve to death.
WRR queuing
WRR queuing schedules all queues in turn to make sure that every queue is served for a certain time, as
shown in Figure 15.
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