Why do motherboards have 10G RJ45?

NablaSquaredG

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Aug 17, 2020
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I've been thinking about this and it doesn't really make sense...

Why do (server) motherboards have 10G RJ45 Ports? 10G RJ45 is power hungry, not well established and has comparably high requirements on the cable.

it would be much better if the 10G RJ45 ports were replaced with 10G SFP+ ports. You could then easily use the onboard networking with existing infrastructure (10G SFP+ switches or 40G switches with breakout cables), save a lot of power and reuse existing SFP+ cables.
SFP+ gives you much more flexibility, because even consumers could decide to use fiber, which is often much easier to hide in home scenarios.
And with SFP+, you still have the option to go with RJ45 if you absolutely need to, by just buying a couple of 10G RJ45 transceivers.

I think every consumer who uses 10G RJ45 nowadays can safely be considered a power user and most of them would probably prefer SFP+ instead of 10G RJ45 because it gives you much more flexibility

It can't reallly be a cost thing, because the Network IC, e.g. Intel X550, works with both 10G RJ45 and SFP+.
The only issue is space on the board, but the existing motherboards with SFP+ ports like the ASUS Z11PA-U12/10G-2S clearly show that it is possible.
 

BlueFox

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Supermicro has sold motherboards with integrated dual SFP+ since the X8 generation (X8DTU-6TF+ for example), so they're available and have been for over a decade. Most consumers would want copper as fiber at home is a rarity and everything else in the consumer realm has been copper.
 
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NablaSquaredG

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Supermicro has sold motherboards with integrated dual SFP+ since the X8 generation (X8DTU-6TF+ for example), so they're available and have been for over a decade.
There are exactly two X11 motherboard with SFP, none of them is dual socket. That doesn't really count. The majority (i.e. the entire -NT line) has 10G RJ45

Most consumers would want copper as fiber at home is a rarity and everything else in the consumer realm has been copper.
The absolute majority of consumers using 10G RJ45 are power users, who would prefer to have the flexibility of fiber (at least according to my surveys with a not too large n)
The rest either doesn't care, doesn't know, doesn't need or only has existing cabling that maybe works for 2.5G

But then again - I'm mainly focusing on Server boards with this post. An X11DPi-NT is not really a consumer board, and, according to Supermicro, not even a workstation board. Or take X11DSF-E, X11DDW-NT, etc...
 

BlueFox

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EATX sized motherboards are a small portion of the server lineup. Most of their products take the AIOM/SIOM modules (or risers like the X12DPU-6) now and forego integrated NICs so that the end-user can choose which networking option they want. I think Supermicro would much rather sell systems than components as that's the direction they've been going for years.
 

RolloZ170

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i know why !!! but i don't tell it !!!

hehe, now serious - ask supermicro (i.e.) that question !
 

i386

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I've been thinking about this and it doesn't really make sense...
My thoughts about 10GBase-T:
- good enough for distances up to 100m (max distance in the standard, but colleagues and friends tested it successfully with longer distances)
- cheap (100m: cat 6a at 78€ vs multimode om4 lszh fibers at 119€)
- cheap again: (because) the work in new buildings is usually already done and existing infrastructure/cabling can be used
I'm mainly focusing on Server boards with this post.
Small businesses use a lot of 10Gbase-t links, (new )sfp+ stuff is too expensive for their demands.
 
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zir_blazer

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I also agree that I find having SFP+ Ports more flexible than standard integrated RJ-45 Ports, giving the fact that fiber seems to be superior on many areas like latency, power consumption, and not being conductive thus giving some extra protection against thunder strikes, plus you still have the chance to purchase a Ethernet module and use it instead on the same Port. Yet, is impossible to even THINK about going full fiber when all mainstream gear is Ethernet, you have to go too out of way.
 

NablaSquaredG

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Aug 17, 2020
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EATX sized motherboards are a small portion of the server lineup. Most of their products take the AIOM/SIOM modules (or risers like the X12DPU-6) now and forego integrated NICs so that the end-user can choose which networking option they want. I think Supermicro would much rather sell systems than components as that's the direction they've been going for years.
The trend is going towards AIOM / OCP, but there's still an awful lot of boards with 10GBase-T
But that doesn't really matter - They could easily replace the 10GBase-T networking on the E-ATX products

My thoughts about 10GBase-T:
- good enough for distances up to 100m (max distance in the standard, but colleagues and friends tested it successfully with longer distances)
My experiments have shown otherwise. 10G is extremely sensitive, existing 1G cabling often only allows 5G or even 2.5G

cheap (100m: cat 6a at 78€ vs multimode om4 lszh fibers at 119€)
100m OS2 LC Duplex UPC = 36,93€ + 2x 10GBase-LR Transceiver á 26,18 € = 89,29€
with the advantage that you can use the same cable for up to 400G!

- cheap again: (because) the work in new buildings is usually already done and existing infrastructure/cabling can be used
But server boards usually don't connect to existing cabling, but rather have a switch nearby, even in very small deployments

Small businesses use a lot of 10Gbase-t links, (new )sfp+ stuff is too expensive for their demands.
I know literally no one using 10GBase-T

//EDIT:
PLUS: 10G SFP+ switches are readily available on the second hand market at very affordable price tags
 
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PigLover

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The answer to "why" is simple: because that is what their customers are asking for.

SM is one of the most market driven manufacturers in this space. They don't try to drive the market the way larger players do. They respond to what their customers are asking for. Most of their products won't even see their first production run unless/until they have an actual customer commitment to purchase in significant quantities.

In the data center customers who have/want fiber based networking do not use the LOM ports for primary networking anyway. They use much higher performance add in cards from Mellanox & others - cards that offer better speeds (25/100/200gbps) have better buffering, more intelligent protocol offloading and other advanced features.
 
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RTM

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I personally like using the typical 1G NICs onboard w. RJ45 ports for management purposes, and while I personally don't need them to be 10G, I suspect that some people may consider it useful to have that slightly greater level of flexibility.
 

Patrick

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A lot of folks have already given the primary reasons. Also remember that 10Gbase-T is backward compatible with 1Gbase-T. So if you design a motherboard with 10Gbase-T you do not need to do SFP+ plus 1Gbase-T on your board or have two different variants of the board.

Also, SFP+ is a declining standard. Most of the industry has transitioned to SFP28 for 25GbE in the data center already, and that shift will continue. SFP+ is an inefficient use of PCIe lanes

I would generally opt for SFP28 but if you ask vendors, often customer requirements are for 1GbE then higher speed in an OCP NIC 3.0 or PCIe card. Above 25GbE features like offloads become important so integrating 25GbE SFP28 may not cost much more than 10GbE SFP+, but if you integrate there will be customers that still want different NICs.
 
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zir_blazer

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A lot of folks have already given the primary reasons. Also remember that 10Gbase-T is backward compatible with 1Gbase-T. So if you design a motherboard with 10Gbase-T you do not need to do SFP+ plus 1Gbase-T on your board or have two different variants of the board.

Also, SFP+ is a declining standard. Most of the industry has transitioned to SFP28 for 25GbE in the data center already, and that shift will continue. SFP+ is an inefficient use of PCIe lanes
But in the same way that you have backwards compatibility with copper Ethernet, you could also use a SFP+ Port with a SFP 1000BASE-T module which are dirt cheap, up to the point that a Motherboard vendor could bundle it with retail units like if it was a SATA Cable or such accessory, so that it works out-of-the-box for standard users yet retain the possibility of doing whatever you want with it later without needing a full PCIe Card. It may be a bit more cumbersome than having a standard Ethernet builtin, but I value that flexibility.

The thing is that even if SFP+ is a declining standard in data center and other high end stuff, it is still better than the mediocre 2.5G/5G Ethernet that they are pushing onto consumer space, which I personally despise. 1G Ethernet has been around like 15 years, and the long overdue upgrade is just either a mere middle point or 1/4 point (Like Intel with its i225-V), so networking technology isn't really tickling down to consumer space the way I was expecting. Yeah, I know that these go easier on existing cables, but if you are going to change everything to get higher speeds, fiber doesn't seem that bad, and if you had to interface these with current gear you could use the SFP Ethernet modules. Having SFP+ would open the doors to a lot of used, cheap 10G Network gear. Yet, it looks like it is too fast for consumer and too slow for current high end...
 

Patrick

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Less reliable though. Adding a SFP+ to 1GbE adapter adds another part that can fail in the chain.
 

Servergeek

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Yeah its a good question. My only guess would be motherboard real estate? Or would SFP stuff run hotter?

10gbe over copper doesnt really make sense, its stupid expensive because of the transceivers (60-150 each, vs like 20 for fiber) so i don't get it either. You are also limited to like 100m most the time anyways.
 

RolloZ170

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security ? some may plug out a fiber connector and look into it to see if there is some light !
that is realy a bad idea.

supposedly the fiber transmitters have limited lifetime (5 years) don't know because i have not tested.
they are freqently swapped and the used/old ones sold cheap on ebay.

cleaning before plug. if not the fiber and or transmitter can be damaged. this may valid only for professional equipment, unsure for "home" stuff.
 
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ca3y6

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On my side, 10gbe switches are still expensive and there are lots of home devices that will only handle 1gbe copper, like a playstation, laptop, sonos, wifi access point, etc. So at best you have a hybrid network. I only run 10gbe between devices that can handle it (NAS, desktop, home server). Everything else is 1gbe. Then what do you install in the walls? If you install fiber, you need expensive switches in every room. And you have to think of resell value, unlikely the next buyer will be as geeky.
 

Patrick

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On my side, 10gbe switches are still expensive and there are lots of home devices that will only handle 1gbe copper, like a playstation, laptop, sonos, wifi access point, etc. So at best you have a hybrid network. I only run 10gbe between devices that can handle it (NAS, desktop, home server). Everything else is 1gbe. Then what do you install in the walls? If you install fiber, you need expensive switches in every room. And you have to think of resell value, unlikely the next buyer will be as geeky.
When I finally finish the fiber piece/ video you may re-think having to have fiber switches in every room.