LevelOne GSW-1676, User Manual, Page: 93 / 150

Q
O
S S
ETTINGS
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QoS Settings
QoS (Quality of Service) is a mechanism which is used to prioritize certain
traffic as it is forwarded through the switch. Both the queue service mode
(strict or weighted round robin), and the method of classifying the priority
of ingress traffic can be configured on this page.
Traffic can be classified as High, Medium, Normal or Low priority. When
the switch is heavily loaded, lower priority traffic is dropped first. You can
select how to prioritize traffic by using one of the QoS modes (none,
802.1p, or DSCP).
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.
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.
Selecting the Method of Priority Processing
This switch supports several common methods of prioritizing traffic to
meet application requirements. It can process traffic priorities specified by
the IEEE 802.1p priority bits in Layer 2 traffic, or the Differentiated
Services Code Point (DSCP) service priority bits found in Layer 3/4
traffic. When either of these services are enabled, the priorities are mapped