Relationship between ACL and Traffic Policy

Hello,
On an S series switch, an ACL is usually used with a traffic policy. A traffic policy defines the traffic classifier matching an ACL and a traffic behavior such as permit/deny associated with the traffic classifier.
The permit/deny rules in an ACL and a behavior in the traffic policy are used in four scenarios.

Note: The traffic policy module permits packets by default. To reject packets between network segments, define the packets to be denied in the ACL. If you add rule permit at the bottom of the ACL, the packets that do not match previous rules will match the last rule. In addition, if the traffic behavior is set to deny, the device discards all packets matching the permit action. As a result, all services are interrupted.
Thanks