Configuring User-Defined Traffic Classes

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These commands are available to configure custom CPU classes that are added to the default list (shown in previous section) in order to address special user requirements:

To add a CPU class, use the command:

CLI (network-admin@switch) > cpu-class-create

                                             

The cpu-class-create command can be used to allocate new CPU traffic queues for special cases that are identified by user-configurable policies.

For instance, when the culprit of a high CPU utilization issue is being investigated in connection with an errant traffic flow (e.g., FTP), the Arista TAC team may recommend configuring a user-defined traffic class with an associated policy to protect the CPU.

In this example a new class TAC-class is created and associated to a rate of 100 pps and automatically allocated to free queue 40:

CLI (network-admin@switch) > cpu-class-create name TAC-class scope local rate-limit 100

CLI (network-admin@switch) > cpu-class-show name TAC-class

name      scope rate-limit hog-protect  hog-protect-support queue

-------   ----- ---------- -----------  ------------------- -----

TAC-class  local 100        disable      none                40

TAC also requests to create/modify a vFlow policy to direct FTP packets to the new CPU class (TAC-class) queue. vFlow match criteria can be freely chosen to match the specific rate limiting need of the user provided they include a to-cpu or copy-to-cpu action for packets:

CLI (network-admin@switch) > vflow-create name myflow scope local in-port 10 proto ftp action to-cpu cpu-class TAC-class

CLI (network-admin@switch) > vflow-show

name   scope type  in-port burst-size precedence action enable cpu-class

------ ----- ----- ------- ---------- ---------- ------ ------ ---------

myflow local vflow  10     auto       default    to-cpu enable TAC-class

Note: CPTP’s vFlow match criteria can be freely chosen to match the specific rate limiting need of the user provided they include a to-cpu or copy-to-cpu action for packets.

After issue resolution, the user can delete a previously created custom CPU class if no longer needed:

CLI (network-admin@switch) > cpu-class-delete

                                             

                                         

Or you can modify the CPU class after creating it:

CLI (network-admin@switch) > cpu-class-modify

Note: You cannot modify the scope of the CPU class. If you want to change the scope, you must delete the existing CPU class and create a new CPU class with the correct scope.