Configuring DSCP policies for codepoints

Use the following commands to configure or reconfigure DSCP policies for codepoints.


qos dscp-map <codepoint> priority <0-7> [name <ascii-string>]

(Optional) This command is required only if an 802.1p priority is not already assigned to the specified <codepoint> in the DSCP Policy table (see Differentiated Services Codepoint (DSCP) mapping).

Valid values for a DSCP codepoint are as follows:
  • A binary value for the 6-bit codepoint from 000000 to 111111.

  • A decimal value from 0 (low priority) to 63 (high priority) that corresponds to a binary DSCP bit set

  • An ASCII standard (hexadecimal) name for a binary DSCP bit set.

Enter ? to display the list of valid codepoint entries.

When the switch applies the specified DSCP policy to a packet, the priority determines the packet's queue in the outbound port to which it is sent. If the packet leaves the switch on a tagged port, it carries the 802.1p priority with it to the next downstream device. For IP packets, the DSCP will be replaced by the codepoint specified in this command.

Default: No-override for most codepoints.

no qos dscp-map <codepoint>

Reconfigures the 802.1p priority for <codepoint> to No-override. Also deletes the codepoint policy name, if configured.

no qos dscp-map <codepoint> name

Deletes only the policy name, if configured, for <codepoint> .

Steps for configuring codepoints:

  1. Determine whether the DSCPs already have priority assignments, which could indicate use by existing applications. (Also, a DSCP must have a priority configured before you can assign any QoS classifiers to use it.)
    Display the current DSCP map configuration
  2. Configure the DSCP policies for the codepoints you want to use.
    Assign priorities to the selected DSCPs