Matching precedence order

当一个数据包是由多个TCAM查找匹配with the same action, a precedence order is followed.

For example, if a packet matches feature 1 with an action to change DSCP toxand a feature 2 with an action to change DSCP toy, the feature 2 action takes precedence and DSCP of the packet will change toy(given that the precedence of feature 2 is greater than that of feature 1). Count-related exception: If a packet matches an IPv4 ACL, a MAC ACL, and a policy with count actions, all the counters increment. Regardless of precedence, if a packet is to be dropped by a configured feature, it will be dropped. Ingress packets do not take precedence over egress packets nor do egress packets take precedence over ingress packets.

The egress TCAM can only increment one counter for the ACLs or policies applied on egress. Only the counter with the highest precedence increments.

The precedence order from highest to lowest is as follows:

Ingress Port IPv6 ACL Ingress Routed VLAN IPv6 ACL Ingress VLAN IPv6 ACL Ingress Port IPv4 ACL Ingress Routed VLAN IPv4 ACL Ingress VLAN IPv4 ACL Ingress Port MAC ACL Ingress VLAN MAC ACL Ingress IPv6 Analytics Data Collection (ADC) Ingress IPv4 Analytics Data Collection (ADC) Ingress Port Policy with IPv6 classes Ingress Port Policy with IPv4 and/or MAC classes Ingress VLAN Policy with IPv6 classes Ingress VLAN Policy with IPv4 and/or MAC classes Ingress Global Policy with IPv6 classes Ingress Global Policy with IPv4 and/or MAC classes IPv6 Control Plane Policing IPv4 Control Plane Policing MAC Control Plane Policing Ingress Control Plane Policing Ingress Routed Port IPv6 Policy Ingress Routed Port IPv4 Policy Ingress Routed VLAN IPv6 Policy Ingress Routed VLAN IPv4 Policy Ingress L3 Statistics Ingress IPv6 VSX Ingress IPv4 VSX Ingress ARP VSX Ingress MAC VSX Egress Routed Port IPv4 ACL Egress Routed VLAN IPv6 ACL Egress VLAN IPv6 ACL Egress Routed VLAN IPv4 ACL Egress VLAN IPv4 ACL Egress Control Plane Policing Egress L3 Statistics