Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

When configuring this feature, you must first create a policy map (sometimes referred to as a service policy or a traffic policy) using the Modular QoS CLI (MQC). Therefore, you should be familiar with the procedure for creating a policy map using the MQC. For more information about creating a policy map (traffic policy) using the MQC, see the “Applying QoS Features Using the MQC” module.

A policy map containing the set qos-group command can only be attached as an input traffic policy. QoS group values are not usable for traffic leaving a device.

The QoS group value is a number between 0 and 99 that is set using the set qos-group command. The group value can be used to classify packets into QoS groups based on a prefix, autonomous system, and community string. A packet is marked with a QoS group value only while it is being processed within the device. The QoS group value is not included in the packet’s header when the packet is transmitted over the output interface. However, the QoS group value can be used to set the value of a Layer 2 or Layer 3 field that is included as part of the packet’s headers (such as the MPLS EXP, CoS, and DSCP fields).

Use the MQC to enable packet classification and marking based on the QoS group value. The MQC is a CLI that allows you to create traffic classes and policies, enable a QoS feature (such as packet classification), and attach these policies to interfaces.

In the MQC, the class-map command is used to define a traffic class that is used to classify traffic (which is then associated with a traffic policy).

The MQC consists of the following three processes:

• Defining a traffic class using the class-map command.

• Creating a traffic policy by associating the traffic class with one or more QoS features (using the policy-map command).

• Attaching the traffic policy to the interface using the service-policy command.

A traffic class contains three major elements: a name, one or more match commands, and, if more than one match command exists in the traffic class, an instruction on how to evaluate these match commands. The traffic class is named in the class-map command line; for example, if you enter the class-mapcisco command while configuring the traffic class in the CLI, the traffic class would be named “cisco.”

The match commands are used to specify various criteria for classifying packets. Packets are checked to determine whether they match the criteria specified in the match commands. If a packet matches the specified criteria, that packet is considered a member of the class and is forwarded according to the QoS specifications set in the traffic policy. Packets that fail to meet any of the matching criteria are classified as members of the default traffic class.

A policy map also contains three major elements: a name, a traffic class to associate with one or more QoS features, and any individual set commands you want to use to mark the network traffic.

1.    enable


2.    configure terminal


3.    class-map class-map-name


4.    match qos-group qos-group-value


5.    end

Device> enable

Device# configure terminal

Device(config)# class-map class1

Device(config-cmap)# match qos-group 30

Device(config-cmap)# end

1.    enable


2.    configure terminal


3.    policy-map policy-map-name


4.    class {class-name | class-default}


5.    set qos-group cos


6.    end


7.    show policy-map


8.    show policy-map policy-map class class-name


9.    exit

Device> enable

Device# configure terminal

Device(config)# policy-map policy1

Device(config-pmap)# class class1

Device(config-pmap-c)# set qos-group cos

Device(config-pmap-c)# end

Device# show policy-map

Device# show policy-map policy1 class class1

Device# exit

1.    enable


2.    configure terminal


3.    interface type number


4.    pvc [name] vpi/vci [ilmi | qsaal | smds]


5.    service-policy {input| output} policy-map-name

6.    end

Device> enable

Device# configure terminal

Device(config)# interface serial4/0/0 

Device(config-if)# pvc cisco 0/16 ilmi

Device(config-if)# service-policy input policy1

Device(config-if-atm-vc)# service-policy input policy1

Device(config-if)# end

Device(config-if-atm-vc)# end