QoS Classification Commands
set dscp
To mark a packet by setting the IP differentiated services code point (DSCP) in the type of service (ToS) byte,
use the set dscp command in policy-map class configuration mode. To remove a previously set DSCP value,
use the no form of this command.
set dscp [tunnel] dscp-value
no set dscp [tunnel] dscp-value
Syntax Description
tunnel
dscp-value
No default behavior or values
Command Default
Policy map class configuration
Command Modes
Command History
Release
Release 6.0
After the DSCP bit is set, other quality-of-service (QoS) services can then operate on the bit settings. The set
Usage Guidelines
dscp is supported only in the ingress direction.
The network gives priority (or some type of expedited handling) to marked traffic. Typically, you set the
DSCP value at the edge of the network (or administrative domain); data then is queued based on the DSCP
value.
Task ID
Task
ID
qos
Examples
In this example, the DSCP ToS byte is set to 6 in the policy map called policy-in. All packets that
satisfy the match criteria of class1 are marked with the DSCP value of 6. The network configuration
determines how packets are marked.
RP/0/RP0/CPU0:router (config)# policy-map policy-in
RP/0/RP0/CPU0:router(config-pmap)# class class1
RP/0/RP0/CPU0:router(config-pmap-c)# set dscp 6
(Optional) Sets the DSCP on the outer IP header. This command is available on Layer 3
interfaces in the ingress direction.
Number from 0 to 63 that sets the DSCP value. Reserved keywords can be specified instead
of numeric values.
Table 2: IP DSCP Reserved Keywords, on page 17
keywords.
Operations
read,
write
Modular QoS Command Reference for Cisco NCS 5500 Series and Cisco NCS 540 Series Routers
set dscp
describes the reserved
Modification
This command was introduced.
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