Linksys LGS308 User Manual page 181

QoS Modes
The QoS mode that is selected applies to all interfaces in the system.
Basic Mode—Class of Service (CoS).
•
All traffic of the same class receives the same treatment, which is the single QoS action of
determining the egress queue on the egress port, based on the indicated QoS value in the
incoming frame. This can be the VLAN Priority Tag (VPT) 802.1p value in Layer 2 and the
Differentiated Service Code Point (DSCP) value for IPv4 or Traffic Class (TC) value for
IPv6 in Layer 3. When operating in Basic Mode, the device trusts this external assigned
QoS value. The external assigned QoS value of a packet determines its traffic class and
QoS.
The header field to be trusted is entered in the Basic QoS page. For every value of that
field, an egress queue is assigned where the frame is sent in the CoS/802.1p to Queue
page or the DSCP to Queue page (depending on whether the trust mode is CoS/802.1p or
DSCP, respectively).
• Disable Mode—In this mode all traffic is mapped to a single best effort queue, so that no
type of traffic is prioritized over another.
When disabling QoS, the shaper and queue setting (WRR/SP bandwidth setting) are reset
to default values. All other user configurations remain intact.
QoS Workflow
To configure general QoS parameters:
1. Choose the QoS mode (Basic, or Disabled by using the Feature Configuration page. The
following steps in the workflow, assume that you have chosen to enable QoS.
2. Assign each interface a default CoS priority by using the Feature Configuration page.
3. Assign the schedule method (Strict Priority or WRR) and bandwidth allocation for WRR to
the egress queues by using the Queue Scheduling page.
4. Set the trusted mode in the Basic QoS page.
5. Designate an egress queue to each IP DSCP/TC value with the DSCP to Queue page. If the
device is in DSCP trusted mode, incoming IP packets are put into the egress queues based
on their DSCP/TC value.
6. Designate an egress queue to each CoS/802.1p priority. If the device is in CoS/802.1
trusted mode, all incoming packets are put into the designated egress queues according
to the CoS/802.1p priority in the packets. This is done by using the CoS/802.1p to Queue
page.
7. Enter bandwidth and rate limits in the following pages:
• Set egress shaping per queue by using the Egress Shaping page.
Set ingress rate limit and egress shaping rate per port by using the Bandwidth
•
Control page.
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