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Priority Commands
Class of Service (CoS) allows data packets that have greater
precedence to receive higher service priority when traffic is
buffered in the switch due to congestion. This switch supports CoS
with four priority queues for each port. Data packets in a port’s
high-priority queues will be transmitted before those in the
lower-priority queues.
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. WRR uses a predefined relative weight for each queue
that determines the percentage of service time the switch services
each queue before moving on to the next queue. This prevents the
head-of-line blocking that can occur with strict priority queuing.
Inbound frames that do not have VLAN tags are tagged with a
default service priority of zero, and placed in queue 1 at the
output port. Therefore, any inbound frames that do not have
priority tags will be placed in queue 1 of the output port. (Note
that if the output port is an untagged member of the associated
VLAN, these frames are stripped of all VLAN tags prior to
transmission.) However, if the incoming frame is an IEEE 802.1Q
VLAN tagged frame, the IEEE 802.1p User Priority bits will be used.
Command Function Mode Page
queue mode Sets the queue mode to strict priority or
Weighted Round-Robin (WRR)
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show queue mode Shows the current queue mode NE,
PE
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