This feature is supported using ConnectX-5 onwards adapter cards.
VXLAN technology provides UDP encapsulation of the ethernet packets. It requires extension of the traditional stateless offloads to avoid performance drop. ConnectX family cards offer the following stateless offloads for a VXLAN packet, similar to the ones offered to non-encapsulated packets.
Available hardware stateless offloads:
Checksum generation (Inner IP and Inner TCP/UDP)
Checksum validation (Inner IP and Inner TCP/UDP)
TSO support for inner TCP packets
RSS distribution according to inner packets attributes
VXLAN tunneling adds 50 bytes (14-eth + 20-ip + 8-udp + 8-vxlan) to the Ethernet frame. System adjusts MTU of the VXLAN interface automatically. Nonetheless, consider account the tunneling overhead of the VXLAN's MTU. Meaning, the MTU of the VXLAN interface must be decremented by 50 bytes (e.g 1450 instead of 1500), or the uplink physical NIC MTU has to be incremented by 50 bytes (e.g 1550 instead of 1500).
The ConnectX-4 adapter cards do not support offload. Please note, this limitation is not detected by the driver.
VLAN interfaces do not report hardware capabilities of the underlying physical interface which provide stateless VXLAN offload. As result, acceleration of VXLAN over VLAN does not work.
SR-IOV Virtual Functions cannot configure UDP VXLAN port. VXLAN acceleration of VFs only work when using a destination UDP port already configured on the physical function