Wfq - HP FlexNetwork MSR Series Configuration Manuals

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 bytes out of each queue in the ascending
order of queue 1 to queue 16. CQ guarantees a certain amount of bandwidth to common packets,
and ensures that mission-critical packets are assigned more bandwidth. The bandwidth ratio for
each queue is the byte count configured for that queue divided by the total byte count configured for
all queues.
CQ can assign free bandwidth of idle queues to busy queues. Even though it performs round robin
queue scheduling, CQ does not assign fixed time slots to 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.
Figure 17 Custom queuing (CQ)
Packets to be sent
through this interface

WFQ

FQ is designed to equally allocate network resources to reduce the delay and jitter of each traffic flow
as much as possible. FQ follows these principles:
•
Different queues have fair dispatching opportunities for delay balancing among flows.
•
Short packets and long packets are equally scheduled. If long packets and short packets exist
in queues, statistically the short packets are scheduled preferentially to reduce the jitter
between packets.
WFQ considers weights when determining the queue scheduling order. Statistically, WFQ gives
high-priority traffic more scheduling opportunities than low-priority traffic. To balance the delay of
every traffic flow, WFQ performs the following operations:
•
Automatically classifies traffic according to the "session" information of traffic.
•
Attempts to provide as many queues as possible for traffic flows.
The session information of traffic includes the following information:
•
Protocol type.
•
TCP or UDP source/destination port numbers.
•
Source/destination IP addresses.
•
IP precedence bits in the ToS field.
Queue 0
Queue 1
Queue 2
......
Queue 15
Classify
Queue 16
Priority
queue
10%
Packets sent
30%
Schedule Sending queue
10%
5%
60
Interface