LevelOne GSW-4876 - Manual (Page 186)

C HAPTER 4 | Configuring the Switch
Quality of Service
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C ONFIGURING E GRESS
P ORT S CHEDULER
Use the QoS Egress Port Schedulers page to show an overview of the QoS
Egress Port Schedulers, including the queue mode and weight. Click on any
of the entries in the Port field to configure egress queue mode, queue
shaper (rate and access to excess bandwidth), and port shaper.
P ATH
Advanced Configuration, QoS, Port Scheduler
P ARAMETERS
These parameters are displayed:
Displaying QoS Egress Port Schedulers
◆ Port – Port identifier.
◆ Mode – Shows the scheduling mode for this port.
◆ Weight – Shows the weight of each egress queue used by the port.
Configuring QoS Egress Port Scheduler, Queue Scheduler and Port Shapers
◆ Scheduler Mode – The switch can be set to service the queues based
on a strict rule that requires all traffic in a higher priority queue to be
processed before the lower priority queues are serviced, or Deficit
Weighted Round-Robin (DWRR) queuing which specifies a scheduling
weight for each queue. (Options: Strict, Weighted; Default: Strict)
DWRR services the queues in a manner similar to WRR, but the next
queue is serviced only when the queue’s Deficit Counter becomes
smaller than the packet size to be transmitted.
Note that weighted scheduling uses a combination of weighted service
for queues 0 - 6, and strict service for the high priority queues 7 and 8.
◆ Queue Shaper – Controls whether queue shaping is enabled for this
queue on this port.
■
Enable – Enables or disables queue shaping. (Default: Disabled)
■
Rate – Controls the rate for the queue shaper. The default value is
500. This value is restricted to 100-1000000 kbps, or 1-3300 Mbps.
■
Unit – Controls the unit of measure for the queue shaper rate as
“kbps” or “Mbps.” (Default: kbps)
■
Excess – Controls whether the queue is allowed to use excess
bandwidth. (Default: Disabled)
◆ Queue Scheduler – When the Scheduler Mode is set to Weighted, you
need to specify a relative weight for each queue. DWRR 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.