I doubt it applies to Randy's 48 port switch (and maybe in general), but for posterity: be advised that the QSFP28 to SFP+ adapter is physically taller than a standard QSFP28 optic, outside of the device. Inside is still to spec of course.

Sort of like how RJ45 SFPs are slightly taller than fiber SFPs, so some switches can't support two rows of them, e.g. Juniper's QFX5100. They CAN fit, but it requires a little persuasion that most people won't be comfortable with.

-Matt

On Wed, Jan 8, 2020, 12:37 Randy Bush <randy@psg.com> wrote:

> I believe that these (and the AOC option) require that the switch
> understand / supports splitting the 40G interface into 4x10s

arcos does what i expect, sub units

as i have no problem wasting ports on the delta box (there are 48 and i
only need two :) i think ben's

https://www.fs.com/products/72582.html

looks to be the simplest solution.

thank you all!

randy