QoS

We have to remember that traffic policy consists of 3 parts:

• Classifier
• Behavior
• Traffic-policy

In brief, to configure a traffic policy:

• define traffic class
• define action to be applied to the traffic class
• associate traffic classifiers and behaviors
• apply the traffic policy to an interface.

Let’s start from ACL.

We have possibility to configure many rules in an ACL. If the ACL is specified in if-match clause, then a packet is matched against multiple rules. If the packet matches a rule in the ACL, then it stops checking against the next rules.

• In a case of DENY action in the ACL, the matched packet is denied, regardless of what traffic behavior defines.
• When PERMIT action is defined in the ACL, then traffic behavior is applied to the matched packet.