diff options
Diffstat (limited to 'doc/guides/nics/enic.rst')
| -rw-r--r-- | doc/guides/nics/enic.rst | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/doc/guides/nics/enic.rst b/doc/guides/nics/enic.rst index cb5ae125..a11627a0 100644 --- a/doc/guides/nics/enic.rst +++ b/doc/guides/nics/enic.rst @@ -252,6 +252,35 @@ Generic Flow API is supported. The baseline support is: More features may be added in future firmware and new versions of the VIC. Please refer to the release notes. +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. + .. _enic_limitations: Limitations @@ -267,9 +296,10 @@ Limitations In test setups where an Ethernet port of a Cisco adapter in TRUNK mode is connected point-to-point to another adapter port or connected though a router instead of a switch, all ingress packets will be VLAN tagged. Programs such - as l3fwd which do not account for VLAN tags in packets will misbehave. The - solution is to enable VLAN stripping on ingress. The follow code fragment is - example of how to accomplish this: + as l3fwd may not account for VLAN tags in packets and may misbehave. One + solution is to enable VLAN stripping on ingress so the VLAN tag is removed + from the packet and put into the mbuf->vlan_tci field. Here is an example + of how to accomplish this: .. code-block:: console @@ -277,6 +307,14 @@ Limitations vlan_offload |= ETH_VLAN_STRIP_OFFLOAD; rte_eth_dev_set_vlan_offload(port, vlan_offload); +Another alternative is modify the adapter's ingress VLAN rewrite mode so that +packets with the default VLAN tag are stripped by the adapter and presented to +DPDK as untagged packets. In this case mbuf->vlan_tci and the PKT_RX_VLAN and +PKT_RX_VLAN_STRIPPED mbuf flags would not be set. This mode is enabled with the +``devargs`` parameter ``ig-vlan-rewrite=untag``. For example:: + + -w 12:00.0,ig-vlan-rewrite=untag + - Limited flow director support on 1200 series and 1300 series Cisco VIC adapters with old firmware. Please see :ref:`enic-flow-director`. |