H3C S5100-SI Operation Manual page 405

1) SP queuing
Figure 1-8 Diagram for SP queuing
SP queuing is specially designed for mission-critical applications. The key feature of
mission-critical applications is that they require preferential service to reduce the response
delay when congestion occurs. Assume that there are eight output queues on the port and
SP queuing classifies the eight output queues on the port into eight classes, which are
queue 7, queue 6, queue 5, queue 4, queue 3, queue 2, queue 1, and queue 0 in the
descending order of priority.
SP queuing schedules the eight queues strictly in 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. By
assigning mission-critical packets to high priority queues and common service packets to
low priority queues, you can ensure that the mission-critical packets are always served
prior to common service packets.
The disadvantage of SP queuing is that packets in the lower priority queues cannot get
served if there are packets in the higher priority queues for a long time when congestion
occurs. This may cause low priority traffic to starve to death.
2) WRR queuing
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