[Ofa_boardplus] Draft Mission Statement

[Hefty, Sean]

> What does "advanced networks" even mean?
> 
> So, I had originally suggested we use "RDMA enabled networks" and that
> got shot down because there is an existing assumption, right or wrong,
> that RDMA equates to IB.  The term advanced networks was really meant
> to encompass any network setup that enables what we would
> traditionally think of as common RDMA functionality.  So, for
> instance, IB and OPA are certainly in there, but we can also run RDMA
> functionality over standard Ethernet using iWARP, or RoCE with a
> lossless Ethernet, or RoCE with ECN enabled on the Ethernet.  But any
> of these Ethernet solutions require additional software/hardware to
> make them work (a soft RoCE or soft iWARP driver, or actual RoCE/iWARP
> hardware, and in some cases specific abilities in the switches), so
> that's what earns them the moniker "advanced networks", because they
> *are* more advanced than a garden variety Ethernet deployment.  But it
> was also meant to encompass any new fabrics that might come around in
> the future assuming they are a good fit for the OFA stacks.
> 
> This then brings up the point, "What is a good fit for the OFA
> stacks?"
> 
> I've tried to pin down the essence of this.  After a lot of thought, I
> think the core, defining element of what is a good fit for the OFA
> stacks is any technology that enables application direct network I/O
> (ADNIO I guess?).  You can't say "it must be RDMA capable" because not
> everything we support is truly RDMA (USNic for one, but even just the
> verbs API has non-RDMA components in that post_send/recv are not truly
> RDMA operations, but instead are merely application direct I/O).  This
> is the thing that separates us from the Berkeley sockets programming
> model more than anything else and catches what all of our current
> implementations do, either in hardware or software.

I too prefer something like application direct I/O over the term RDMA.  However, I wonder if we shouldn't use the term 'fabric' instead of 'network' with additional qualifiers.