5. Specify a CoS value to assign to incoming packets.
Note
• When DSCP is enabled on a port, incoming packets are tagged with the specified CoS value.
The packets are then processed in order of priority according to their CoS value and which
queue the CoS value is mapped to.
• QSS uses CoS 802.1p priority tag values which range from 0 to 7. By default, they are each
mapped to the queue of the same number, where queue 0 receives the lowest priority and
queue 7 the highest priority. To change the default mappings, see
• QSS does not override the CoS values of incoming packets that have already been assigned
CoS values.
6. Click Save.
QSS saves the QoS settings.
Mapping CoS values to queues
QSS supports 8 queues for each switch port. Different queues receive different priority in the network traffic,
where queue 0 receives the lowest priority and queue 7 receives the highest priority.
By default, CoS values 0-7 each map to the queue of the same number. Therefore, a data packet with CoS
value 0 would be put in queue 0 and processed last, after data packets with higher CoS values have been
processed. However, you can change this default mapping by assigning different queues to the CoS values.
You can also assign the same queue to more than one CoS value.
1. Log in to QSS.
2. Go to Configuration > QoS > CoS Mapping .
3. Assign a queue for each CoS value.
4. Click Save.
QSS saves the mappings.
Mapping DSCP values to queues
Differentiated Services Code Point (DSCP) is a field in the header of an IP packet that is used to provide QoS
optimization. You can map DSCP values to queues to determine the priority of incoming IP packets based on
their DSCP values.
Queue 0 receives the lowest priority, while queue 7 receives the highest priority.
By default, QSS assigns the following queues to the following DSCP value ranges.
DSCP Values
Queue
0-7
0
8-15
1
16-23
2
24-31
3
32-39
4
QSW Managed Switches User Guide
QSS
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