"generic" QFSP to RJ45 breakout cables?

thetoad

Active Member
Feb 10, 2021
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nothing, but isn't that qfsp to sfp? i.e. not rj45. I've found many of those, but nothing little that has rj45 tranceivers on the end of the breakout side.
 

klui

Well-Known Member
Feb 3, 2019
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LOL. I didn't notice what you were asking. Frankly that's such a specialized item I feel you'll be paying a premium. And I don't think the site's image is correct as it shows an SFP+. There are no images that depict its description on the web either.
 

thetoad

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Feb 10, 2021
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I agree, as I said, was mostly thinking about it as a theoretical thing, less about practical.
 

BoredSysadmin

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Mar 2, 2019
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SFP+ modules to 1G Base-T are dirt cheap on fleebay. I'd just get QSFP to 4x SPF+ break-out cable as one above and get 4x SFP 1G copper modules separately.
 

NablaSquaredG

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Aug 17, 2020
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SFP+ modules to 1G Base-T are dirt cheap on fleebay. I'd just get QSFP to 4x SPF+ break-out cable as one above and get 4x SFP 1G copper modules separately.
And how are you planning to connect the SFP+ RJ45 modules to the Breakout? a
As far as I know, there is no "Dual female QSFP+" adaptor.
 

BoredSysadmin

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NablaSquaredG

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Aug 17, 2020
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That defies the entire point of having a QSFP->RJ45 breakout cable. You have 4 additional devices you need to power and position somewhere.
or
Cool thing, but doesn't allow connecting a QSFP+ breakout to an SFP+ transceiver like you proposed.
 

LodeRunner

Active Member
Apr 27, 2019
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I found this from Dell Dell Networking Cable QSFP+ to 4 x 10/100/1000BASE-T (RJ45) Copper Breakout Cable 1 meter : Display Solutions | Dell Greece

but am wondering if there's any company that makes a more "generic" (i.e. more affordable) one (or at least a set of SKUs with different trancievers on the QFSP end)

in my case for mellanox, though in practice, not the biggest deal in the world, mostly just wondering.
I have never heard of such a thing, and all the search results seem to come back to this one Dell part. The only images I have found of it do not show it breaking out to 4x RJ45. I strongly suspect that this is a horribly mis-labeled part and is actually a regular QSFP to 4x 10G SFP+ DAC breakout.
 

BoredSysadmin

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Mar 2, 2019
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That defies the entire point of having a QSFP->RJ45 breakout cable. You have 4 additional devices you need to power and position somewhere.
True, but an alternative to keep costs low. That of course won't be a very elegant engineering solution. OP said it was more of a theoretical discussion.

Cool thing, but doesn't allow connecting a QSFP+ breakout to an SFP+ transceiver as you proposed.
True again. That one I found while searching. seems a bit wasteful to go from a 40gig port to 2x 10gig, but it's a) cheap and b) has a small form factor.
 

thetoad

Active Member
Feb 10, 2021
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I have never heard of such a thing, and all the search results seem to come back to this one Dell part. The only images I have found of it do not show it breaking out to 4x RJ45. I strongly suspect that this is a horribly mis-labeled part and is actually a regular QSFP to 4x 10G SFP+ DAC breakout.
that's what I might have thought, but the description doubles down on it.

- Features an QSFP+ connector at one end and RJ45 connector at the other end

But as I wrote above, this was mostly me thinking out loud.