[Beowulf] Has DDR IB gone the way of the Dodo?

NiftyOMPI Mitch niftyompi at niftyegg.com
Wed Oct 1 13:18:04 PDT 2008


On Wed, Oct 1, 2008 at 11:19 AM, Jan Heichler <jan.heichler at gmx.net> wrote:

>  Hallo Prentice,
>
> Mittwoch, 1. Oktober 2008, meintest Du:
>
> PB> And what is the status of DDR? Are people still using it, or has it
>
> PB> already been replaced by QDR in the marketplace?
>
>
> DDR is still the most important Infiniband in the market. DDR provides
> enough bandwidth for most applications at the moment because most
> applications suffer from latency - not limited bandwidth. QDR is more
> interesting for building spine networks. And QDR might get more important if
> we see more cores in typical compute nodes.
>
>
> >> Cisco does appear to be transitioning to *other* technologies.  Again,
>
> >> they aren't the only IB provider out there (seems such a shame, gobbling
>
> >> up TopSpin and then effectively discarding them).
>
>
> PB> What *other* technolgies are you talking about QDR IB, or something
>
> PB> other than IB altogether, like 10 Gb Ethernet, or something all new and
>
> PB> proprietary?
>
>
> Cisco is dropping IB - probably to go for 10GE. It was a short time for
> Cisco offering IB solutions - bur probably they weren't very successful.
>

Yes folks tell me that Cisco is backing away from the IB business -- all the
parts on the Cisco price book
that I know of were rebranded products and I suspect that some of their
providers were too happy to
sell directly to customers at a discount sometimes below the OEM price.
Perhaps more
importantly IB is not a router and management rich  layer. i.e.  It does not
facilitate all the routing
and management value add that Cisco focuses on for their bread and butter.

They are however well involved and commited in Open MPI which is agnostic to
the transport layer beyond the want to go fast part.

I know that QLogic has well specified and tested cables for sale.   Call the
Qlogic "King of Prussia, Penn" office and tell them what you want.  Gore and
Leoni make excellent cables as do others.

QDR is interesting... in all likelyhood the QDR game will be optical for any
link further away than a single rack.  Once IB goes optical there will be a
lot of reason to install IB in machine rooms and campus sites
that are just out of reach today.

I should say that copper QDR is hard but not impossible.  IMO optical has
advantages and once it becomes easy for the end user (site) to install
optical it should change the game.
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