Quality of Service
QoS Features and Components
Cisco Small Business 300 Series Managed Switch Administration Guide 414
22
The header field to be trusted is entered in the Global Settings 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,
respective ly).
•Advanced Mode—Per-flow Quality of Service (QoS).
In advanced mode, a per flow QoS consists of a class map and/or a policer:
-A class map defines the kind of traffic in a flow, and contains one or more
ACLs. Packets that match the ACLs belong to the flow.
-A policer applies the configured QoS to a flow. The QoS configuration of
a flow may consist of egress queue, the DSCP or CoS/802.1p value, and
actions on out of profile (excess) traffic.
•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.
Only a sing le mode ca n be active at a time. When the sy stem is con figured to w ork
in QoS Advanced mode, settings for QoS Basic mode are not active and vice
versa.
When the mode is changed, the following occurs:
•When changing from QoS Advanced mode to any other mode, policy profile
definitions and class maps are deleted. ACLs bonded directly to interfaces
remain bonde d.
•When changing from QoS Basic mode to Advanced mode, the QoS Trust
mode configuration in Basic mode is not retained.
•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, perform the following:
STEP 1 Choose the QoS mode (Basic, Advanced, or Disabled, as described in the “QoS
Modes” section) for the system by using the QoS Properties page. The following
steps in the workflow, assume that you have chosen to enable QoS.
STEP 2 Assign each interface a default CoS priority by using the QoS Properties page.