- CB Marking requires CEF
- Packets are classified based on the logic in the MQC class maps
- An MQC policy map refers to one or more class maps using the class class-map-name command, packets classified into that class are then marked
- CB Marking is enabled for packets either entering or exiting an interface using the MQC service policy in/out interface subcommand.
- A CB marking policy map is processed sequentially, after a packet has matched a class it is marked based on the set commands defined for that class
- You can configure multiple set commands in one class to set multiple fields
- Packets that do not explicitly match a defined class are considered to have matched a special class called class-default
- For any class inside the policy map for which there is no ser command, packets in that class are not marked.