Re: Extend LID space in InfiniBand beyond 48k? Is this really possible?

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Wed, Mar 29, 2017 at 06:07:47PM +0200, Vangelis Tasoulas wrote:
> Hello,
>
> I was reading a year+ old article where Steve Scott (CRAY CTO) was
> interviewed here:
> https://www.nextplatform.com/2016/01/08/cray-cto-connects-the-dots-on-future-interconnects/
>
> At a certain point Steve mentions (or at least that's what the article
> claims):
>
> /InfiniBand has another limit in terms of the number of logical IDs, or
> LIDs, it can support, which is around 48,000 end points, and for the
> most point, people have stayed within that limit. There is an extended
> version that has some higher packet overhead that can go to higher
> scalability./
>
> Is this true? Is there any reference that one can point me to for the
> part of the "extended version that has some higher packet overhead that
> can go to higher scalability"?
>
> To the best of my knowledge, there is no extended version defined in the
> InfiniBand specification. What is mentioned is that /The unicast LID
> range is a flat identifier space defined as 0x0001 to 0xBFFF./

Right, there is no any extended version of that spec.
As far as I know, Intel's OmniPath technology is marketed as new and
extended version of Infiniband [1], so it is probably that he referenced to it.

[1] http://www.intel.com/content/www/us/en/high-performance-computing-fabrics/omni-path-architecture-fabric-overview.html

>
> Vangelis
>




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