+ uses this interrupt to get information about link status and errors
+ in the fast path.
+
+.. _enic-flow-director:
+
+Flow director support
+---------------------
+
+Advanced filtering support was added to 1300 series VIC firmware starting
+with version 2.0.13 for C-series UCS servers and version 3.1.2 for UCSM
+managed blade servers. In order to enable advanced filtering the 'Advanced
+filter' radio button should be enabled via CIMC or UCSM followed by a reboot
+of the server.
+
+With advanced filters, perfect matching of all fields of IPv4, IPv6 headers
+as well as TCP, UDP and SCTP L4 headers is available through flow director.
+Masking of these feilds for partial match is also supported.
+
+Without advanced filter support, the flow director is limited to IPv4
+perfect filtering of the 5-tuple with no masking of fields supported.
+
+Ingress VLAN Rewrite
+--------------------
+
+VIC adapters can tag, untag, or modify the VLAN headers of ingress
+packets. The ingress VLAN rewrite mode controls this behavior. By
+default, it is set to pass-through, where the NIC does not modify the
+VLAN header in any way so that the application can see the original
+header. This mode is sufficient for many applications, but may not be
+suitable for others. Such applications may change the mode by setting
+``devargs`` parameter ``ig-vlan-rewrite`` to one of the following.
+
+- ``pass``: Pass-through mode. The NIC does not modify the VLAN
+ header. This is the default mode.
+
+- ``priority``: Priority-tag default VLAN mode. If the ingress packet
+ is tagged with the default VLAN, the NIC replaces its VLAN header
+ with the priority tag (VLAN ID 0).
+
+- ``trunk``: Default trunk mode. The NIC tags untagged ingress packets
+ with the default VLAN. Tagged ingress packets are not modified. To
+ the application, every packet appears as tagged.
+
+- ``untag``: Untag default VLAN mode. If the ingress packet is tagged
+ with the default VLAN, the NIC removes or untags its VLAN header so
+ that the application sees an untagged packet. As a result, the
+ default VLAN becomes `untagged`. This mode can be useful for
+ applications such as OVS-DPDK performance benchmarks that utilize
+ only the default VLAN and want to see only untagged packets.