+Item: ``FLEX``
+^^^^^^^^^^^^^^
+
+Matches with the custom network protocol header that was created
+using rte_flow_flex_item_create() API. The application describes
+the desired header structure, defines the header fields attributes
+and header relations with preceding and following protocols and
+configures the ethernet devices accordingly via
+rte_flow_flex_item_create() routine.
+
+- ``handle``: the flex item handle returned by the PMD on successful
+ rte_flow_flex_item_create() call, mask for this field is ignored.
+- ``length``: match pattern length in bytes. If the length does not cover
+ all fields defined in item configuration, the pattern spec and mask are
+ considered by the driver as padded with trailing zeroes till the full
+ configured item pattern length.
+- ``pattern``: pattern to match. The pattern is concatenation of bit fields
+ configured at item creation. At configuration the fields are presented
+ by sample_data array. The order of the bitfields is defined by the order
+ of sample_data elements. The width of each bitfield is defined by the width
+ specified in the corresponding sample_data element as well. If pattern
+ length is smaller than configured fields overall length it is considered
+ as padded with trailing zeroes up to full configured length, both for
+ value and mask.
+
+Item: ``L2TPV2``
+^^^^^^^^^^^^^^^^^^^
+
+Matches a L2TPv2 header.
+
+- ``flags_version``: flags(12b), version(4b).
+- ``length``: total length of the message.
+- ``tunnel_id``: identifier for the control connection.
+- ``session_id``: identifier for a session within a tunnel.
+- ``ns``: sequence number for this date or control message.
+- ``nr``: sequence number expected in the next control message to be received.
+- ``offset_size``: offset of payload data.
+- ``offset_padding``: offset padding, variable length.
+- Default ``mask`` matches flags_version only.
+
+Item: ``PPP``
+^^^^^^^^^^^^^^^^^^^
+
+Matches a PPP header.
+
+- ``addr``: PPP address.
+- ``ctrl``: PPP control.
+- ``proto_id``: PPP protocol identifier.
+- Default ``mask`` matches addr, ctrl, proto_id.
+