H3C S5810 Series, Руководство по эксплуатации

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6-3
Figure 6-2 Schematic diagram for WRR queuing
Assume there are eight output queues on a 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 to the queue. On
a 100 Mbps port, you can configure the weight values of WRR queuing to 50, 30, 10, 10, 50, 30, 10, and
10 (corresponding to w7, w6, w5, w4, w3, w2, w1, and w0 respectively). In this way, the queue with the
lowest priority is assured of 5 Mbps of bandwidth at least, thus avoiding the disadvantage of SP queuing
that packets in low-priority queues may fail to be served for a long time.
Another advantage of WRR queuing is that while the queues are scheduled in turn, the service time for
each queue is not fixed, that is, if a queue is empty, the next queue will be scheduled immediately. This
improves bandwidth resource use efficiency.
The S5810 series use group-based WRR queuing. You can assign the output queues to WRR
scheduling group 1 and WRR scheduling group 2 as required. Note that the queues in the same group
must be consecutive. The device preferentially schedules the group containing the highest queue ID.
Suppose queue 0, queue 1, queue 2, and queue 3 are assigned to WRR scheduling group 1, and queue
4, queue 5, queue 6, and queue 7 are assigned to WRR scheduling group 2. WRR is performed in WRR
scheduling group 2 preferentially. When no packet is to be sent in WRR scheduling group 2, WRR is
performed in WRR scheduling group 1. .
SP+WRR queue scheduling algorithm
You can implement SP+WRR queue scheduling on a port by assigning some queues on the port to the
SP scheduling group and the others to the WRR scheduling group (that is, group 1). Packets in the SP
scheduling group are scheduled preferentially. When the SP scheduling group is empty, packets in the
WRR scheduling group are scheduled. Queues in the SP scheduling group are scheduled by SP.
Queues in the WRR scheduling group are scheduled by WRR.