Question about the classification process of the Cisco QoS.
I understand the concept, but I have some misunderstanding regarding the Cisco QoS algorithm.
Am I true with the following reasoning:
The interface A is configured with a service policy SP. SP is a policy map, containing 4 class map. Each class map match a different dscp value.
So, when a packet arrive in the interface A, switch retrieve the policy map associated. Then, the switch, check if packet match with each class map configured, successively, until a match occur or not (like ACL) When it match, the packet is considered as classified, and, the policy defined (policing, shaping, etc) in the class map section is applied.
Is it true ?
Could we say that the process classification is performed from the order of the class map appear in the policy map ?
Or, for each packet arriving in an interface, regardless the interface, do Cisco try to classify them independently from the policy map configured, based on all class map available in the switch ? and then, when the classification is done, the switch take the policy map associated, and know already which class map is relevant ?