Web Management Guide-R05

Table Of Contents
Chapter 9
| Class of Service
Layer 3/4 Priority Settings
– 216 –
Setting Priority
Processing to
DSCP or CoS
The switch allows a choice between using DSCP or CoS priority processing
methods. Use the Priority > Trust Mode page to select the required processing
method.
Command Usage
If the QoS mapping mode is set to DSCP, and the ingress packet type is IPv4,
then priority processing will be based on the DSCP value in the ingress packet.
If the QoS mapping mode is set to DSCP, and a non-IP packet is received, the
packet’s CoS and CFI (Canonical Format Indicator) values are used for priority
processing if the packet is tagged. For an untagged packet, the default port
priority (see page 211) is used for priority processing.
If the QoS mapping mode is set to CoS, and the ingress packet type is IPv4, then
priority processing will be based on the CoS and CFI values in the ingress
packet.
For an untagged packet, the default port priority (see page 211) is used for
priority processing.
Parameters
These parameters are displayed:
Port – Port identifier. (Range: 1-26/52)
Trust Mode
CoS – Maps layer 3/4 priorities using Class of Service values. (This is the
default setting.)
DSCP – Maps layer 3/4 priorities using Differentiated Services Code Point
values.
Web Interface
To configure the trust mode:
1. Click Traffic, Priority, Trust Mode.
2. Set the trust mode for any port.
3. Click Apply.