Operation Manual – QoS
H3C S3610&S5510 Series Ethernet Switches
Chapter 4 Congestion Management
4-3
Queue 1 Weight 1
……
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
Figure 4-2
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.
H3C S3610 and S5510 Series Ethernet Switches support the following three queue
scheduling algorithms:
z
All the queues are scheduled through the SP algorithm.
z
All the queues are scheduled through the WRR algorithm.
z
Some queues are scheduled through the SP algorithm, while other queues are
scheduled through the WRR algorithm.
4.3 Configuring an SP Queue
Follow these steps to configure SP queues:
