HP 5830 Series Configuration Manual page 47

Compared with WRR, WFQ can work with the minimum guaranteed bandwidth as follows:
• By setting the minimum guaranteed bandwidth, you can make sure that each WFQ queue is
assured of certain bandwidth.
The assignable bandwidth is allocated based on the priority of each queue (assignable bandwidth
•
= total bandwidth – the sum of minimum guaranteed bandwidth of each queue).
For example, assume that the total bandwidth of a port is 10 Mbps and that the port has five flows, with
the precedence being 0, 1, 2, 3, and 4 and the minimum guaranteed bandwidth being 128 kbps, 128
kbps, 128 kbps, 64 kbps, and 64 kbps, respectively.
The assignable bandwidth = 10 Mbps – (128 kbps + 128 kbps + 128 kbps + 64 kbps + 64 kbps)
•
= 9.5 Mbps.
The total assignable bandwidth quota is the sum of all the (precedence value + 1)s, 1 + 2 + 3 + 4
•
+ 5 = 15.
• The bandwidth percentage assigned to each flow is the (precedence value of the flow + 1)/total
assignable bandwidth quota. The bandwidth percentages for the flows are 1/15, 2/15, 3/15,
4/15, and 5/15, respectively.
The bandwidth assigned to a queue = the minimum guaranteed bandwidth + the bandwidth
•
allocated to the queue from the assignable bandwidth.
SP+WRR queuing
You can assign some queues on a port to the SP scheduling group and the others to the WRR scheduling
group (group 1) to implement SP + WRR queue scheduling. The switch schedules packets in the SP
scheduling group preferentially, and when the SP scheduling group is empty, it schedules the packets in
the WRR scheduling group. Queues in the SP scheduling group are scheduled with the SP queue
scheduling algorithm. Queues in the WRR scheduling group are scheduled with WRR.
SP+WFQ queuing
SP+WFQ queuing is similar to SP+WRR queuing. You can assign some queues on a port to the SP
scheduling group and others to the WFQ scheduling group to implement SP + WFQ queue scheduling.
The switch first uses SP queuing to schedule the queues in the SP scheduling group, then schedules
packets of queues in the WFQ group based on their minimum guaranteed bandwidth settings when the
SP scheduling group is empty, and at last uses WFQ to schedule the queues in the WFQ scheduling
group in a round robin fashion according to their weights.
NOTE:
Both Layer 2 and Layer 3 Ethernet interfaces support the congestion management function. The term
"interface" in this chapter collectively refers to these two types of interfaces. You can use the port
link-mode command to configure an Ethernet port as a Layer 2 or Layer 3 interface (see
Switching Configuration Guide
).
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Layer 2—LAN