Installation manual

3-226
SIGNAMAX LLC • www.signamax.eu
Selecting the Queue Mode
You can set the switch to service the queues based on a strict rule that requires all traffic
in a higher priority queue to be processed before lower priority queues are serviced, or
use Weighted Round-Robin (WRR) queuing that specifies a relative weight of each
queue.
Command Usage
• Strict priority requires all traffic in a higher priority queue to be processed before lower
priority queues are serviced.
• WRR uses a relative weighting for each queue which determines the amount of packets
the switch transmits every time it services each queue before moving on to the next
queue. Thus, a queue weighted 8 will be allowed to transmit up to 8 packets, after which
the next lower priority queue will be serviced according to it’s weighting. This prevents
the head-of-line blocking that can occur with strict priority queuing.
Command Attributes
• WRR - Weighted Round-Robin shares bandwidth at the egress ports by using
scheduling weights with default values of 1, 2, 4, 8 for queues 0 through 3, respectively.
(This is the default selection.)
• Strict - Services the egress queues in sequential order, transmitting all traffic in the
higher priority queues before servicing lower priority queues.
Web – Click Priority, Queue Mode. Select Strict or WRR, then click Apply.
Figure 3-126 Queue Mode
CLI – The following sets the queue mode to strict priority service mode.
Setting the Service Weight for Traffic Classes
This switch uses the Weighted Round Robin (WRR) algorithm to determine the frequency
at which it services each priority queue. As described in “Mapping CoS Values to Egress
Queues” on page 3-224, the traffic classes are mapped to one of the four egress queues
provided for each port. This weight sets the limit for the number of packets the switch will
transmit each time the queue is serviced, and subsequently affects the response time for
software applications assigned a specific priority value.
Console(config)#queue mode strict 4-296
Console(config)#exit
Console#show queue mode 4-299
Queue mode: strict