HP FlexNetwork 6600, Руководство по настройке

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packets in the queue with the second highest priority. In this way, you can assign the mission-critical
packets to the high priority queue to make sure that they are always served first. The common
service packets are assigned to the low priority queues and transmitted when the high priority
queues are empty.
The disadvantage of priority queuing is that packets in the lower priority queues cannot be
transmitted if packets exist in the higher queues for a long time when congestion occurs.
CQ
Figure 18 Custom queuing (CQ)
CQ provides 17 queues, numbered from 0 to 16. Queue 0 is a reserved system queue, and queues
1 through 16 are customer queues, as shown in
Figure 18 . You can define traffic classification rules
and assign a percentage of interface/PVC bandwidth for each customer queue. By default, packets
are assigned to queue 1.
During a cycle of queue scheduling, CQ first empties the system queue. Then, it schedules the 16
queues in a round robin way: it sends a certain number of packets (based on the percentage of
interface bandwidth assigned for each queue) out of each queue in the ascending order of queue 1
to queue 16. CQ guarantees normal packets a certain amount of bandwidth, and ensures that
mission-critical packets are assigned more bandwidth.
CQ can assign free bandwidth of idle queues to busy queues. Even though it performs round robin
queue scheduling, CQ does no assign fixed time slots for the queues. If a queue is empty, CQ
immediately moves to the next queue. When a class does not have packets, the bandwidth for other
classes increases.