Cisco ASR 901 User Manual

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Cisco ASR 901 Aggregation Services Router Command Reference Guide
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Chapter 1 CLI Command Reference
set precedence
Using This Command with the Enhanced Packet Marking Feature
If you are using this command as part of the Enhanced Packet Marking feature, you can use this
command to specify the “from-field” packet-marking category to be used for mapping and setting the
precedence value. The “from-field” packet-marking categories are as follows:
• CoS
• QoS group
If you specify a “from-field” category but do not specify the table keyword and the applicable
table-map-name argument, the default action will be to copy the value associated with the “from-field”
category as the precedence value. For instance, if you configure the set precedence cos command, the
CoS value will be copied and used as the precedence value.
You can do the same for the QoS group-marking category. That is, you can configure the set precedence
qos-group command, and the QoS group value will be copied and used as the precedence value.
The valid value range for the precedence value is a number from 0 to 7. The valid value range for the
QoS group is a number from 0 to 99. Therefore, when configuring the set precedence qos-group
command, note the following points:
• If a QoS group value falls within both value ranges (for example, 6), the packet-marking value will
be copied and the packets will be marked.
• If QoS group value exceeds the precedence range (for example, 10), the packet-marking value will
not be copied, and the packet will not be marked. No action is taken.
Setting Precedence Values for IPv4 Packets Only
To set the precedence values for IPv4 packets only, use a command involving the ip keyword like the
match ip precedence or match ip dscp command or include the match protocol ip command along
with the others in the class map. Without the additional ip keyword, the class-map may match both IPv6
and IPv4 packets (depending on the other match criteria) and the set precedence or set dscp command
may act upon both types of packets.
Examples The following example shows how to use the set precedence command.
Router(config)# policy-map policy-cos
Router(config-pmap)# class class-default
Router(config-pmap-c)# set precedence 4
Router(config-pmap-c)# end
The set precedence command is applied when you create a service policy in QoS policy-map
configuration mode. This service policy is not yet attached to an interface or to an ATM virtual circuit.
For information on attaching a service policy to an interface, refer to the “Modular Quality of Service
Command-Line Interface Overview” chapter of the Cisco IOS Quality of Service Solutions
Configuration Guide.
Related Commands Command Description
match dscp Identifies a specific IP DSCP value as a match criterion.
match precedence Identifies IP precedence values as match criteria.
match protocol Configures the match criteria for a class map on the basis of the specified
protocol.
policy-map Creates or modifies a policy map that can be attached to one or more
interfaces to specify a service policy.

Cisco ASR 901 Specifications

General

Brand	Cisco
Model	ASR 901
Category	Network Router
Language	English