H3C Technologies H3C S3100 Series Switches - Manual (Page 400)

Operation Manual – QoS
H3C S3100-52P Ethernet Switch Chapter 1 QoS Configuration
1-7
Figure 1-5
Diagram for WRR
WRR queue-scheduling algorithm schedules all the queues in turn and every queue
can be assured of a certain service time. Assume there are eight priority queues on a
port. WRR configures a weight value for each queue, which is w7, w6, w5, w4, w3, w2,
w1, and w0. The weight value indicates the proportion of obtaining resources. On a 100
M port, configure the weight value of WRR queue-scheduling algorithm to 50, 50, 30,
30, 10, 10, 10, and 10 (corresponding to w7, w6, w5, w4, w3, w2, w1, and w0 in order).
In this way, the queue with the lowest priority can get 5 Mbps bandwidth at least, and
the disadvantage of SP queue-scheduling that the packets in queues with lower priority
may not get service for a long time is avoided. Another advantage of WRR queue 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. In this way, the
bandwidth resources are made full use.
1.2 QoS Supported by S3100-52P
Table 1-4
QoS functions supported by S3100-52P and related commands
QoS Specification Related command
Priority mapping
Support only the mapping
between 802.1p priority and
local queues
qos
cos-local-precedence-map
Port priority Supported
priority
priority-level
priority
trust
Queue
scheduling
Support SP and WRR
Support queue scheduling
configuration synchronization
on aggregated ports
queue-scheduler