HP FlexNetwork MSR Series Configuration Manuals page 61

Figure 15 FIFO queuing
Packets to be sent
through this interface
PQ
PQ is designed for mission-critical applications. Mission-critical applications require preferential
treatment to reduce the response delay when congestion occurs. PQ can flexibly determine the
order of forwarding packets by network protocol (for example, IP and IPX), incoming interface,
packet length, source/destination address, and so on. Priority queuing classifies packets into four
queues (top, middle, normal, and bottom queues, in descending priority order). By default, packets
are assigned to the normal queue. Each of the four queues is a FIFO queue.
As shown in
packets in the queue with the highest priority first. When the queue with the highest priority is empty,
it sends packets in the queue with the second highest priority. To make sure mission-critical packets
are always served first, assign the mission-critical packets to the highest-priority queue. The
common service packets that are assigned to the low-priority queues are transmitted when the
high-priority queues are empty.
However, packets in the lower-priority queues cannot be transmitted when congestion occurs if
packets exist in the higher-priority queues for a long time.
Figure 16 Priority queuing (PQ)
Packets to be sent out
this interface
CQ
CQ provides 17 queues, numbered from 0 to 16. Queue 0 is a system queue, and queues 1 through
16 are user queues, as shown in
bandwidth across user queues by specifying the byte count for each queue. By default, packets are
assigned to queue 1.
Queue
Figure 16, PQ schedules the four queues in descending order of priority. It sends
Top queue
Middle queue
Normal queue
Classify
Bottom queue
Figure
Packets sent
Interface
Sending queue
Packets sent
Schedule
Sending queue
17. You can define traffic classification rules and divide
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Interface