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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-nam
e 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.
