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SFP+ to RJ45 connection

danb35

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Aug 16, 2011
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jgreco

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That's neat. I hadn't seen those before and despite searching, never found them.
They didn't exist until just recently. The amount of power available to your typical SFP+ slot is substantially less than the amount of power needed to drive 10G-on-copper over any sort of distance, so these new modules are typically severely length-limited as to the run they can support reliably. Additionally, because SFP+ modules require some "driver" foo onboard your switch or chipset, there's a good chance that they won't work {well, at all} on devices that weren't built to accommodate them.

My takeaway is that you shouldn't use these without a damn good reason, and that my traditional suggestion of buying the proper optics and some fiber is much more generally compatible.
 

purduephotog

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Jan 14, 2013
Messages
73
They didn't exist until just recently. The amount of power available to your typical SFP+ slot is substantially less than the amount of power needed to drive 10G-on-copper over any sort of distance, so these new modules are typically severely length-limited as to the run they can support reliably. Additionally, because SFP+ modules require some "driver" foo onboard your switch or chipset, there's a good chance that they won't work {well, at all} on devices that weren't built to accommodate them.

My takeaway is that you shouldn't use these without a damn good reason, and that my traditional suggestion of buying the proper optics and some fiber is much more generally compatible.
Totally agree here. It's more "Hey, I have ONE MORE option!".

I'd even be cool with running an auxiliary power supply to them :)
 

JaimieV

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Oct 12, 2012
Messages
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If you go SFP+ from the desktop you'll have to run the SFP+ cable (or fibre between SFP+ transceivers) through your cabling route, which may be more troublesome than RJ45.

I went RJ45 throughout since my desktop is an iMac Pro where I can't change to SFP+ and I only have the one machine to connect fastwise to the NAS. Intel X540 dual RJ45 10gigE in the NAS, single 10m cat6 cable between the two, hard-coded IPs.
(Primary NAS and backup NAS have a direct 10gigE link for backups from the other port)
A one gig port on the NAS connects to the house network, as does wifi on the Mac. All good.

I did a lot of dithering about going SFP+ with an ex-datacentre ebay switch, but as I was going SAS at the same time there were just too many new things at once for me and too many possibilities of transceivers not being compatible etc etc. The QNAP QSW-804-4C almost tempted me but it's a bit expensive.
 

c32767a

Senior Member
Joined
Dec 13, 2012
Messages
362
They didn't exist until just recently. The amount of power available to your typical SFP+ slot is substantially less than the amount of power needed to drive 10G-on-copper over any sort of distance, so these new modules are typically severely length-limited as to the run they can support reliably. Additionally, because SFP+ modules require some "driver" foo onboard your switch or chipset, there's a good chance that they won't work {well, at all} on devices that weren't built to accommodate them.

My takeaway is that you shouldn't use these without a damn good reason, and that my traditional suggestion of buying the proper optics and some fiber is much more generally compatible.
It's also important to note that with the additional power requirements comes additional heat load. Even if the power rails can support the 10GBaseT SFP+, the enclosure may not be able to reject enough heat for it to operate within specs.
 

omcn7

Junior Member
Joined
May 19, 2015
Messages
19
Should work.
Just remark of sfpp adapter , check with chelsio support if msa is supported anda that adapter has msa
I bought two SFP+ to RJ45 modules (used) hoping at least one of them would work. Sadly the Chelsio 10GB 2-Port PCI-e OPT Adapter Card 110-1088-30 does not seem to work with either the ipolex - 10G SFP+ RJ45 Copper Transceiver or the Fibay- 10G SFP+ to RJ45 for Cisco SFP-10G-T Netgear AXM765 Mikrotik . It is possible I am not configuring the network properly to direct connect, or perhaps I need a crossover cable if I am not using a switch? Just some possible caution there when using the Chelsio cards maybe. I ended up buying the microtik 10Gbe Switch several others have mentioned here. It should arrive in a couple days.
Mods: I forget the rules for URL links. I changed them from amazon smile to just normal but I don't know if that makes them ix affiliate links?
 
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jgreco

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No. SFP+ does not provide enough power to drive 10GBase-T, but manufacturers desperate to drive adoption have created "low-power" units anyways which can only drive 10GBase-T over a much shorter distance than standard. Further, your card or switch also needs to support the SFP+, which is actually a complex electronic device with its own "driver" needs. What this really means is that these SFP+-to-RJ45 transceivers are a lot less useful than you might think. You can use them on devices that have been designed to work with them. For everything else, it's really better to use vendor optics and fiber.
 

Jessep

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Aug 19, 2018
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292

blanchet

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Apr 17, 2018
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STH has tested many SFP+-to-10G-BASE-T adapters:


According to the reviews, they work well. Some of them support also 2.5GbE and 5 GbE.
 

omcn7

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Joined
May 19, 2015
Messages
19
No. SFP+ does not provide enough power to drive 10GBase-T, but manufacturers desperate to drive adoption have created "low-power" units anyways which can only drive 10GBase-T over a much shorter distance than standard. Further, your card or switch also needs to support the SFP+, which is actually a complex electronic device with its own "driver" needs. What this really means is that these SFP+-to-RJ45 transceivers are a lot less useful than you might think. You can use them on devices that have been designed to work with them. For everything else, it's really better to use vendor optics and fiber.
Thanks for the reply. I elected to pick up Microtik 10Gbe switch CRS305-1G-4S+IN , once you start the add up the cost of modules the switch is cheaper and gives me more options. From my research the switch shows as compatible with the SFP+ to RJ45 modules I mentioned in the links above above. For the 2x Chelsio 10GB 2-Port PCI-e OPT Adapter Card I am just using DAC cables to connect to the switch. I have not had issues with the DAC cables when directly attached from my hypervisor to the FreeNAS. I also picked up another SFP+ module from 10Gtek SFP+ to RJ45 Copper Module . I figured since I bought the above 2 modules second hand, I would get a brand new module just in case I got bad modules. Plus in my experience 10Gtek has been pleasant to work with, their DAC cables are excellent.

Wish me luck I am about to do tests.. my runs are not super long, they just happen to be cat6 instead of fiber.

#Several days later...

Hi I have been having a heck of a time finding an SFP+ to rj45 module that works in my network?

The switch is a Mikrotik CRS305-1G-4S+IN
There are three NICs I need to communicate with
2x Chelsio 10GB 2-Port PCI-e OPT Adapter Card 110-1088-30 (2 SFP+ ports)
1x Aquantia AQC107 which is an onboard NIC for the ASRock x470 Taichi Ultimate x470 Motherboard

I also have DAC Cables 2m and 1m I am using 10G SFP+ DAC Cable - 10GBASE-CU Passive Direct Attach Copper Twinax SFP Cable for Cisco SFP-H10GB-CU2M, Ubiquiti, D-link, Supermicro, Netgear, Mikrotik, Open Switch Devices,

These DAC cables work with the switch and can ping the dell R710 host and the Supermicro FreeNAS host. I can not ping a host connected to the same switch with a SFP+ to rj45 adapter.

I have tried the following modules:
10gtek
SFP+ to RJ45 Copper Module - 10GBase-T Transceiver for Cisco SFP-10G-T-S, Ubiquiti UF-RJ45-10G, Netgear, D-Link, Supermicro, TP-Link, Broadcom, Linksys, up to 30m

ipolex
10G SFP+ RJ45 Copper Transceiver, 10GBase-T Module for Cisco SFP-10G-T-S, Ubiquiti, D- Link, Supermicro, Netgear, Mikrotik (Cat6a/7, 30-Meter)

and

fibay
10G SFP+ to RJ45 for Cisco SFP-10G-T Netgear AXM765 Mikrotik Finisar 10GBase-T SFP+ Transceiver Module Copper, Cat6a/7, 30M

I can get a DHCP lease on these but they will not ping out to anything else on the switch.

Ideally I would direct attach without the switch but (inform me if I am incorrect) these old Chelsio NICs do not have compatiable SFP+ to rj45 modules because the card does not supply enough power.

To connect the RJ-45 runs I have flexboot cat6 cables from monoprice, they are only 5 foot runs while I am testing.

I have cat6 but the run is too long and jumpers through a cat6 patch panel and two wall jacks to get from NAS to Workstation which is too much for 10gbe plus the run is approx 60 meters.

The run will be approx 55-60 meters and I will upgrade that run to cat6a or cat 7 depending on your recommendation. I could also go fiber if that works better?

I can put a 10GBe card in my workstation with SFP+. The supermicro has all it's PCIE slots taken so I only have the option of replacing the chelsio card with something else like an intel x540-T2.

The switch can be part of the mix or taken out and just direct attach SFP+ or 10Gbase-T cables. All the runs are short the problem comes in with the workstation being about 200 feet away. Any help is appreciated , thanks!
 
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omcn7

Junior Member
Joined
May 19, 2015
Messages
19
These DAC cables work with the switch and can ping the dell R710 host and the Supermicro FreeNAS host. I can not ping a host connected to the same switch with a SFP+ to rj45 adapter.
Several weeks later..
I have to admit there is no issue with any of the cables or modules I mentioned.. I *literally* got my wires crossed.. in my rack. My darn cable labels fell off (darn cheap label maker).. So I was guessing and.. yeah. So that was the issue. :oops:o_O
 
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