Configuring an SP Queue 879
Figure 261 Diagram for WRR queuing
A port of the switch supports eight outbound queues. The WRR queue-scheduling
algorithm schedules all the queues in turn to ensure that every queue can be
assigned a certain service time. Assume there are eight output queues on the port.
The eight weight values (namely, w 7, w 6, w 5, w 4, w 3, w 2, w 1, and w 0)
indicating the proportion of assigned resources are assigned to the eight queues
respectively. On a 100M port, you can configure the weight values of WRR
queue-scheduling algorithm 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 can be assured of 5 Mbps of bandwidth at least, thus avoiding
the disadvantage of SP queue-scheduling algorithm that packets in low-priority
queues are possibly not to be served for a long time. Another advantage of WRR
queue-scheduling algorithm is that though the queues are scheduled in turn, the
service time for each queue is not fixed, that is to say, if a queue is empty, the next
queue will be scheduled immediately. In this way, the bandwidth resources are
fully utilized.
3Com Switch 4800G Family support the following three queue scheduling
algorithms:
■ All the queues are scheduled through the SP algorithm.
■ All the queues are scheduled through the WRR algorithm.
■ Some queues are scheduled through the SP algorithm, while other queues are
scheduled through the WRR algorithm.
Configuring an SP
Queue
Configuration Procedure Follow these steps to configure SP queues:
Queue 1 Weight 1
ĂĂ
Queue 2 Weight 2
Queue N-1 Weight N-1
Queue N Weight N
Packets to be sent through
this port
Sent packets
Interface
Queue
scheduling
Sending queue
Packet
classification
To do… Use the command… Remarks
Enter system view system-view -
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