Configuring an SP Queue 879Figure 261 Diagram for WRR queuingA port of the switch supports eight outbound queues. The WRR queue-schedulingalgorithm schedules all the queues in turn to ensure that every queue can beassigned 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 queuesrespectively. On a 100M port, you can configure the weight values of WRRqueue-scheduling algorithm to 50, 30, 10, 10, 50, 30, 10, and 10 (correspondingto w7, w6, w5, w4, w3, w2, w1, and w0 respectively). In this way, the queue withthe lowest priority can be assured of 5 Mbps of bandwidth at least, thus avoidingthe disadvantage of SP queue-scheduling algorithm that packets in low-priorityqueues are possibly not to be served for a long time. Another advantage of WRRqueue-scheduling algorithm is that though the queues are scheduled in turn, theservice time for each queue is not fixed, that is to say, if a queue is empty, the nextqueue will be scheduled immediately. In this way, the bandwidth resources arefully utilized.3Com Switch 4800G Family support the following three queue schedulingalgorithms:■ 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 arescheduled through the WRR algorithm.Configuring an SPQueueConfiguration Procedure Follow these steps to configure SP queues:Queue 1 Weight 1ĂĂQueue 2 Weight 2Queue N-1 Weight N-1Queue N Weight NPackets to be sent throughthis port Sent packetsInterfaceQueueschedulingSending queuePacketclassificationTo do… Use the command… RemarksEnter system view system-view -
