[dpdk-users] Configure FCS offload

[dpdk-users] Configure FCS offload

[Chaney, Benjamin]

Hello,
                How can a dpdk application configure the NIC to offload the computation of the Ethernet frame check sequence? I have found a fair amount of documentation about offloading IPv4 and UDP checksums, but not mention of doing the same for the FCS.
Thanks,
                Ben

Re: [dpdk-users] Configure FCS offload

[Wiles, Keith]

On 6/28/16, 1:25 PM, "users on behalf of Chaney, Benjamin" <users-bounces@dpdk.org on behalf of bchaney@akamai.com> wrote:

>Hello,
>                How can a dpdk application configure the NIC to offload the computation of the Ethernet frame check sequence? I have found a fair amount of documentation about offloading IPv4 and UDP checksums, but not mention of doing the same for the FCS.

Normally the Frame Checksum (as I call it, which is not technically correct) is done by the MAC chip as the packet is transmitted, which is the last four bytes to be sent. If you want the FCS to be DMAed into memory on RX then normally the NIC supports that feature or you can have the NIC strip the FCS bytes on the frame.

The descriptor for the RX packet normally tells you the FCS is valid and you do not need the FCS bytes. What is it you want the FCS for or maybe I am misunderstanding your question?

>Thanks,
>                Ben
>