Users Guide

Specifying WRED Drop Precedence
You can configure the WRED drop precedence in an output QoS policy.
● Specify a WRED profile to yellow and/or green traffic.
QOS-POLICY-OUT mode
wred
For more information, refer to Applying a WRED Profile to Traffic.
DSCP Color Maps
This section describes how to configure color maps and how to display the color map and color map configuration.
This sections consists of the following topics:
● Creating a DSCP Color Map
● Displaying Color Maps
● Display Color Map Configuration
Creating a DSCP Color Map
You can create a DSCP color map to outline the differentiated services codepoint (DSCP) mappings to the appropriate color
mapping (green, yellow, red) for the input traffic. The system uses this information to classify input traffic on an interface based
on the DSCP value of each packet and assigns it an initial drop precedence of green, yellow, or red
The default setting for each DSCP value (0-63) is green (low drop precedence). The DSCP color map allows you to set the
number of specific DSCP values to yellow or red. Traffic marked as yellow delivers traffic to the egress interface, which will
either transmit or drop the packet based on configured queuing behavior. Traffic marked as red (high drop precedence) is
dropped.
Important Points to Remember
● All DSCP values that are not specified as yellow or red are colored green (low drop precedence).
● A DSCP value cannot be in both the yellow and red lists. Setting the red or yellow list with any DSCP value that is already in
the other list results in an error and no update to that DSCP list is made.
● Each color map can only have one list of DSCP values for each color; any DSCP values previously listed for that color that
are not in the new DSCP list are colored green.
● If you configured a DSCP color map on an interface that does not exist or you delete a DSCP color map that is configured on
an interface, that interface uses an all green color policy.
To create a DSCP color map:
1. Create the color-aware map QoS DSCP color map.
CONFIGURATION mode
qos dscp-color-map color-map-name
2. Create the color aware map profile.
DSCP-COLOR-MAP
dscp {yellow | red} {list-dscp-values}
3. Apply the map profile to the interface.
CONFIG-INTERFACE mode
qos dscp-color-policy color-map-name
Example: Create a DSCP Color Map
The following example creates a DSCP color map profile, color-awareness policy, and applies it to interface 1/11.
696
Quality of Service (QoS)