[dpdk-users] Outer VLAN stripping X710 NIC

[dpdk-users] Outer VLAN stripping X710 NIC

[Tomáš Jánský]

Hello DPDK Team,

I am having an issue with the behavior of Intel X710 NIC and would like
some clarification.
When the card receives packets with QinQ (double 802.1Q) the RX_RSS based
on L3 and L4 information is not working without specifying
DEV_RX_OFFLOAD_VLAN_EXTEND.
However, by specifying the mentioned flag, the card automatically strips
outer VLAN from the packet (even without using other offload flags like
DEV_RX_OFFLOAD_VLAN_STRIP) while leaving only the inner VLAN in the packet.
I know that the TCI from the stripped VLAN can be found in rte_mbuf
structure, but is it possible to force the card to keep the outer VLAN in
the packet (and still maintain working RSS)?
I do not know, whether this is an issue with DPDK design or the X710 NIC
itself. I was unable to find any useful information in the card datasheet.

Any clarification on this topic would be greatly appreciated.
Thanks in advance.

All the best
Tom

Re: [dpdk-users] Outer VLAN stripping X710 NIC

[Iain Barker]

I posted my observations on the same issue a year or so ago...
See my follow-ups on this thread for a patch to work around the problem:

http://mails.dpdk.org/archives/users/2017-October/002530.html

Note that the patch has real-time overhead so was rejected.
But we are using it to good effect in our production systems.