Information About FEX-based ACL Classification
The Fabric Extender (FEX) based Access Control List (ACL) Classification feature uses ternary content addressable memory (TCAM) resources on a FEX to perform ACL-based packet classification of incoming packets on the switch.
Overview of FEX-based ACL Classification
The FEX-based ACL Classification feature uses TCAM resources on a FEX to perform ACL-based packet classification of incoming packets on the switch. When QoS policies are processed on a FEX, the policies are enforced on the switch and on the associated FEX or FEXes.
By default this feature is disabled. When the feature is enabled, and if the existing system-level QoS policy is accepted by the FEX, the QoS policy is enforced by the FEX. If the existing system-level QoS policy is not accepted by the FEX, an error message is displayed and the fabric ports associated with the FEX are error-disabled, which prevents the FEX from being online.
If the feature is disabled, the existing system-level QoS policy is removed from the FEX and the enforcement of the existing QoS policy is changed from ACL-based to CoS-based. The TCAM entries are removed and packet classification on the FEX is done using the cos2q map in the FEX hardware.
- System level QoS policies are enforced on a FEX in the ACL-based approach. That is, TCAM entries are created and programed on FEX ASICs. If the QoS policy is not accepted on a FEX, the command is rejected and an error message is generated. A system level QoS policy is always programmed and enforced completely on the switches and all associated FEXes.
- Interface level QoS policies are enforced on the FEX. That is, TCAM entries in the corresponding FEX ASIC are taken and programmed. If the QoS policy is not accepted on the target interface, the command is rejected and an error message is generated.