[ofiwg] raw Ethernet support

[Christoph Lameter]

There are multiple elements to this since one would need l2 and l3 access.

On the l2 level you would use the MAC address for packets and then format
the content of the frames yourself. This would allow support of an
arbitrary ethernet protocol. Applications would have to be able to set the
MAC addresses where they would like to receive traffic (multiple in order
to support broadcast and multicast addresses).

On the l3 level the IP address would be used as the address and supportive
functions are available (like NIC calculation / verification of checksums
and the remainder of the typically provided offload for regular NICs).

The flow steering API kind of covers both of these levels to some extend
but it is something to the side.

The fundmantal idea is that these protocols would allow the use of the
Fabric API to generate IP datagrams and thereby native IP format traffic
can be supported. This allows writing of userspace frabric communication
layers based on IP that would work with commodity hardware.

For us also the effect is that we would like to create a user space IP
stack and use the fabric API to communicate directly with IP based servers
and services that may just operate with a standard OS IP stack. The fabric
API then works as an way to bypass the operating system.

This is solution that currently works very well for us. We do both IP based
and IB based communication through the IBverbs/RDMA apis.


On Fri, Jul 18, 2014 at 7:45 PM, Hefty, Sean <sean.hefty at intel.com> wrote:

> Christoph,
>
> In the last meeting, you mentioned adding an Ethernet protocol option.
>  That's easy enough to add, but can you provide some lower-level details on
> what you're looking for (or confirm the items below)?
>
> Would an app use MAC addresses directly?  (Add an FI_MAC fi_addr_format.)
>
> Would input buffers into data transfer operations be the Ethernet frame
> data?  (I.e. the input buffers would NOT include the MAC header.)
>
> Can you think of any other changes that would be needed to fully support
> data transfers over a raw Ethernet endpoint?
>
> - Sean
>
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