Rate Limit - HP 830 Series Configuration Manual

packets in the queue with the second highest priority, and so on. You can assign mission-critical packets
to the high priority queue to make sure the high priority queue packets are always served first and assign
common service (such as Email) packets to the low priority queues so they are sent when the high priority
queues are empty.
Packets in the lower priority queues cannot be transmitted if the higher priority queues have packets,
which can cause lower priority traffic to starve to death.
WRR queuing
WRR queuing schedules all the queues in turn to make sure every queue can be served for some time, as
shown in Figure
Figure 482 WRR queuing
A typical switch provides four output queues per port. WRR assigns each queue a weight value
(represented by w3, w2, w1, or w0) to decide the proportion of resources assigned to the queue. On a
100 Mbps port, you can set the weight values of WRR queuing to 50, 25, 25, and 25 (corresponding
to w3, w2, w1, and w0, respectively). In this way, the queue with the lowest priority is assured of a
minimum of 20-Mbps bandwidth, and the disadvantage of SP queuing (that packets in low-priority
queues may fail to be served for a long time) is avoided.
WRR queuing improves bandwidth resource use efficiency by not setting a fixed service time for each
queue. If a queue is empty, the next queue will be scheduled immediately.
You can implement SP + WRR queue scheduling on a port by assigning some queues on the port to the
SP scheduling group when you configure WRR. Packets in the SP scheduling group are scheduled
preferentially by SP. When the SP scheduling group is empty, the other queues are scheduled by WRR.

Rate limit

Rate limit is a traffic control method using token buckets. The rate limit of a physical interface specifies the
maximum rate for forwarding packets (including critical packets). Rate limit can limit all the packets
passing a physical interface.
Traffic evaluation and token bucket
A token bucket is a container that holds a certain number of tokens, as shown in
puts tokens into the bucket at a set rate. When the token bucket is full, the extra tokens will overflow.
482.
473
Figure 483. The system