36-44
Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
Chapter 36 Configuring QoS
Configuring Standard QoS
This example shows how to create a class map called
class2
, which matches incoming traffic with DSCP
values of 10, 11, and 12.
Switch(config)#
class-map class2
Switch(config-cmap)#
match ip dscp 10 11 12
Switch(config-cmap)#
end
Switch#
This example shows how to create a class map called
class3
, which matches incoming traffic with
IP-precedence values of 5, 6, and 7:
Switch(config)#
class-map class3
Switch(config-cmap)#
match ip precedence 5 6 7
Switch(config-cmap)#
end
Switch#
Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps
You can configure a policy map on a physical port that specifies which traffic class to act on. Actions
can include trusting the CoS, DSCP, or IP precedence values in the traffic class; setting a specific DSCP
or IP precedence value in the traffic class; and specifying the traffic bandwidth limitations for each
matched traffic class (policer) and the action to take when the traffic is out of profile (marking).
A policy map also has these characteristics:
•
A policy map can contain multiple class statements, each with different match criteria and policers.
•
A separate policy-map class can exist for each type of traffic received through a port.
•
A policy-map trust state and a port trust state are mutually exclusive, and whichever is configured
last takes affect.
Follow these guidelines when configuring policy maps on physical ports:
•
You can attach only one policy map per ingress port.
•
If you configure the IP-precedence-to-DSCP map by using the
mls qos map ip-prec-dscp
dscp1...dscp8
global configuration command, the settings only affect packets on ingress interfaces
that are configured to trust the IP precedence value. In a policy map, if you set the packet IP
precedence value to a new value by using the
set ip precedence
new-precedence
policy-map class
configuration command, the egress DSCP value is not affected by the IP-precedence-to-DSCP map.
If you want the egress DSCP value to be different than the ingress value, use the
set dscp
new-dscp
policy-map class configuration command.
•
If you enter or have used the
set ip dscp
command, the switch changes this command to
set dscp
in
its configuration.
•
You can use the
set ip precedence
or the
set precedence
policy-map class configuration command
to change the packet IP precedence value. This setting appears as
set ip precedence
in the switch
configuration.
•
A policy-map and a port trust state can both run on a physical interface. The policy-map is applied
before the port trust state.
