DAC vs. Fiber vs. Standard Copper Ethernet Durability - Sit-Stand Desk

[NateR]

Hello all,

I just purchased a used Brocade 6450-24p off eBay, and am working on getting the hardware ordered for using the SFP+ 10gbe ports.

I've got a sit-stand desk for my desktop, which will be one of the devices connected to a 10gbe port.

Ideally I'd go with rj-45 modules on both ends, but between the module cost and the high power usage, I'm looking at DAC and fiber as alternatives.

From what I've read, the overall price difference between DAC and fiber isn't much. Fiber would be great for its flexibility in terms of range (in the likely event I move my servers to another room in the next year or two), but my concern is durability when repeatedly flexed. I've got some channel on the legs of my desk that would prevent pinching, but how does fiber stand up to repeated, gentle flexing (not a tight turn radius) in the long-term? I wouldn't imagine it would be an issue, but I've not worked with fiber, and I just generally think of it being used in static installations.


Thank you

 

[Tom5051]

DAC is more durable than fiber but limited to cable length. Fiber doesn't mind being moved a lot as long as you don't bend it to sharply.
I ruined a fiber cable when part of it got trapped under the leg of my couch and I didn't notice, crushed it to the point of no signal.
Fiber cables are cheap, the transceivers are the bits that cost the most.

 

[Sean Ho]

I think if you cable manage properly around your sit-stand desk, fiber should be just fine. Usually for <= 3m distances, DAC is cheaper than fiber + 2x SFP+ optics.

 

[LodeRunner]

DAC is more durable than fiber but limited to cable length. Fiber doesn't mind being moved a lot as long as you don't bend it to sharply.
I ruined a fiber cable when part of it got trapped under the leg of my couch and I didn't notice, crushed it to the point of no signal.
Fiber cables are cheap, the transceivers are the bits that cost the most.

You can get bend-insensitive fiber. Wrap it around a pencil and it won't care, so apart from something extreme, like a hairpin bend or crushing it, it's fairly resilient. Mechanically, I would expect good OM3/4 or OS2 fiber to outlast stranded copper (the usual for patch cables).

I think if you cable manage properly around your sit-stand desk, fiber should be just fine. Usually for <= 3m distances, DAC is cheaper than fiber + 2x SFP+ optics.

The only downside of a DAC in this scenario is that they are thick and can be quite stiff. I think my DACs are thicker than the 120V/20A rated power cables I use. But, yeah, at the lengths DACs support, it will usually be cheaper than two transceivers + cable (FS.com optics at $20 ea; I have not yet seen RJ45 SFP+ for less than $60 ea).

 

[Sean Ho]

Used 10GbaseSR optics are super cheap in bulk on eBay, but yes DAC is usually even cheaper.

I've had some pretty thin DACs, but yeah even the thin ones are less flexible than cat6 or fiber. They are pretty sturdy; some of my old DACs are practically kinked and still work.