and RFC 4115 Two Rate Three Color Marker (trTCM)
* Policer actions (per meter output color): recolor, drop
* Statistics (per policer output color)
+* Chaining multiple meter objects
+* Protocol based input color selection
Configuration steps
-------------------
which is why the MTR objects are enabled through a special "meter" action.
The MTR objects are created and updated in their own name space (``rte_mtr``)
-within the ``librte_ether`` library. Whether an MTR object is private to a
+within the ``librte_ethdev`` library. Whether an MTR object is private to a
flow or potentially shared by several flows has to be specified at its
creation time.
color blind mode, which is equivalent to considering all input packets
initially colored as green.
-* Policing: There is a separate policer action configured for each meter
- output color, which can:
-
- * Drop the packet.
-
- * Keep the same packet color: the policer output color matches the meter
- output color (essentially a no-op action).
-
- * Recolor the packet: the policer output color is set to a different color
- than the meter output color. The policer output color is the output color
- of the packet, which is set in the packet meta-data (i.e. struct
- ``rte_mbuf::sched::color``).
+* There is a meter policy API to manage pre-defined policies for meter.
+ Any rte_flow action list can be configured per color for each policy.
+ A meter object configured with a policy executes the actions per packet
+ according to the packet color.
* Statistics: The set of counters maintained for each MTR object is
configurable and subject to the implementation support. This set includes
the number of packets and bytes dropped or passed for each output color.
+
+API walk-through
+----------------
+
+.. _figure_rte_mtr_chaining:
+
+.. figure:: img/rte_mtr_meter_chaining.*
+
+ Meter components
+
+This section will introduce the reader to the critical APIs to use
+the traffic meter and policing library.
+
+In general, the application performs the following steps to configure the
+traffic meter and policing library.
+
+#. Application gets the meter driver capabilities using ``rte_mtr_capabilities_get()``.
+#. The application creates the required meter profiles by using the
+ ``rte_mtr_meter_profile_add()`` API function.
+#. The application creates the required meter policies by using the
+ ``rte_mtr_meter_policy_add()`` API function.
+#. The application creates a meter object using the ``rte_mtr_create()`` API
+ function. One of the previously created meter profile
+ (``struct rte_mtr_params::meter_profile_id``) and meter policy
+ (``struct rte_mtr_params::meter_policy_id``) are provided as arguments
+ at this step.
+#. The application enables the meter object execution as part of the flow action
+ processing by calling the ``rte_flow_create()`` API function with one of the
+ flow action set to ``RTE_FLOW_ACTION_TYPE_METER`` and the associated
+ meter object ID set to this meter object.
+#. The API allows chaining the meter objects to create complex metering topology
+ by the following methods.
+
+ * Adding multiple flow actions of the type ``RTE_FLOW_ACTION_TYPE_METER`` to
+ the same flow.
+ Each of the meter action typically refers to a different meter object.
+
+ * Adding one (or multiple) actions of the type ``RTE_FLOW_ACTION_TYPE_METER``
+ to the list of meter actions (``struct rte_mtr_meter_policy_params::actions``)
+ specified per color as show in :numref:`figure_rte_mtr_chaining`.
+
+Protocol based input color selection
+------------------------------------
+
+The API supports selecting the input color based on the packet content.
+Following is the API usage model for the same.
+
+#. Probe the protocol based input color selection device capabilities using
+ the following parameters with ``rte_mtr_capabilities_get()`` API.
+
+ * ``struct rte_mtr_capabilities::input_color_proto_mask;``
+ * ``struct rte_mtr_capabilities::separate_input_color_table_per_port``
+
+#. When creating the meter object using ``rte_mtr_create()``, configure
+ relevant input color selection parameters such as
+
+ * Fill the tables ``struct rte_mtr_params::dscp_table``,
+ ``struct rte_mtr_params::vlan_table`` based on input color selected.
+
+ * Update the ``struct rte_mtr_params::default_input_color`` to determine
+ the default input color in case the input packet does not match
+ the input color method.
+
+#. Use the following APIs to configure the meter object
+
+ * Select the input protocol color with ``rte_mtr_color_in_protocol_set()`` API.
+
+ * If needed, update the input color table at runtime using
+ ``rte_mtr_meter_vlan_table_update()`` and ``rte_mtr_meter_dscp_table_update()``
+ APIs.
+
+ * Application can query the configured input color protocol and its associated
+ priority using ``rte_mtr_color_in_protocol_get()`` and
+ ``rte_mtr_color_in_protocol_priority_get()`` APIs.