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.