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4.8 QoS Setting
The Quality of Service(QoS) Setting includes Priority Mode and Class of Service (CoS)
Configuration. QoS refers to mechanisms in the network software that make the actual
determination of which packets have priority. CoS refers to feature sets, or groups of services,
that are assigned to users based on company policy. If a feature set includes priority
transmission, then CoS is implemented in QoS functions within the routers and switches in
the network. In an enterprise network, class of service (CoS) differentiates high-priority
traffic from lower-priority traffic. Tags may be added to the packets to identify such classes,
but without delivery guarantee like the quality of service (QoS) functions, which are
implemented in the network devices.
4.8.1 Priority Mode
There are three priority modes available to specify the priority of packets being serviced.
These include First-In-First-Out, All-High-Before-Low, and Weight-Round-Robin.
First-In-First-Out:
Packets are placed into the queue and serviced in the order they were received.
All-high-before-Low(Strict priority)
：
All packets will be assigned to either high priority queue
(Queue 2) or low priority queue (Queue 1). The packet on the low priority queue
will not be forwarded until the high priority queue is empty.
WRR mode:
There are 4 priority queues for Weighted-and-round-robin (WRR) mode.
When this mode is selected, the traffic will be forwarded according to the number
set in each queue.
