Queue Scheduling; Traffic-Based Traffic Statistics; Red - H3C S7500 Series Operation Manual

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Operation Manual – QoS

H3C S7500 Series Ethernet Switches

Packets to be sent

through an interface

Figure 1-6 Diagram for WRR

The WRR queue scheduling algorithm schedules all the queues in turn and every

queue can be assured of a certain service time. Assume there are 8 priority queues on

a port. The WRR queue scheduling algorithm assigns a weight value to each queue,

which are w7, w6, w5, w4, w3, w2, w1, and w0 respectively. The weight value indicates

the proportion of obtaining resources. On a 100M port, configure the weight value of

WRR queue-scheduling algorithm to 50, 50, 30, 30, 10, 10, 10 and 10 to w7, w6, w5, w4,

w3, w2, w1, and w0 respectively. In this way, the queue with the lowest priority can get

5Mbps bandwidth at least, and the disadvantage of the SP queue scheduling algorithm

that the packets in queues with lower priority may get no service for a long time is

avoided. Another advantage of the WRR queue scheduling algorithm is that: though the

queues are scheduled in order, 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.

The traffic-based traffic statistics feature is to use ACL rules for traffic identifying and

perform traffic statistics on the packets matching the ACL rules. You can get the

statistics of the packets you are interested in through this feature.

When severe congestion occurs, the switch can adopt the random early detection

(RED) algorithm to solve the problem of excessive congestion and avoid global TCP

synchronization caused by the tail-drop algorithm.

Queue 2 Weight 2

Queue N-1 Weight N-1

Queue N Weight N

Chapter 1 QoS Configuration

warding direction

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