We originally bought several of the MikroTik S+RJ10 modules when they first came out, and were, well disappointed. Although the MikroTik S+RJ10 carries the same model number, there is an enormous delta between the first and second revision parts. In our review, we are going to discuss the newer rev 2.16 version.
MikroTik S+RJ10 Overview
The MikroTik S+RJ10 is a relatively simple to understand device. One end plugs into a standard SFP+ port on a switch, and the other has a RJ45 port. Essentially, the S+RJ10 converts a SFP+ port into a standard copper networking port.
It goes a bit beyond a standard RJ45 in this case. These types of adapters have been available for years going from a 10GbE SFP+ port to a 1GbE RJ45 port. Even only 3 years ago major vendors were selling SFP+ to 10Gbase-T adapters for thousands of dollars. Power consumption and heat are so much higher with 10GbaseT, and the SFP+ module is so compact, that that was a major concern. Now, using the Marvell 88X3310P, we have solutions like the S+RJ10 that can run at only 2.4W on a 30m 10Gbase-T link and therefore fit in many switches.
Beyond enabling the ecosystem, there are other benefits. First cost. MSRP on these modules is $65, but street price is $55 +/- $4. If you have a 10Gbase-T device, such as a server, or NAS, this relatively low cost makes it economical to add 10Gbase-T to a SFP+ switch.
The switch in these photos is actually the CRS326-24S+2Q+RM which is in our review queue, but you could use them with the MikroTik CRS305-1G-4S+IN or CRS317-1G-16S+RM as examples. We even took the WinBox image below with one working in a 2015 era MikroTik CRS226-24G-2S+IN. Given the additional power that these use, and it is significant in MikroTik’s switch products, you need to consult with a reseller and MikroTik’s documentation on how many you can use in a switch and if there are any changes to switch behavior such as fans that will need to turn on if you use them.
Although we have discussed 10Gbase-T here, that is not entirely accurate. Technically, the S+RJ10 supports 10/100, 1GbE, 2.5GbE, and 5GbE speeds as well. This is designed to deliver Nbase-T connectivity. If you have a SFP+ switch like the MikroTik CRS309-1G-8S+IN you can add one of these to attach the one-off 2.5GbE/ 5GbE NAS, AP, or workstation as well.
On that note, there are some caveats to saying this works at 2.5Gbase-T, 5Gbase-T, and 10Gbase-T speeds. That is cable length and cable type. Here is MikroTik’s official table:
10Gbase-T runs are limited to 30m even over Cat7. The 100-200m limitations are worth being aware of if you are running in an office or home as wiring through conduits often goes further than one estimates. If you have a rack or smaller office space, 30m is ok, but remember that each module will use considerably more power with 10Gbase-T speeds, more at the 30m mark.
A Quick Note MikroTik S+RJ10 Rev 1 v. Rev 2.16
These modules went through an important revision in their lifecycle. The Rev 1 modules were a bit rough around the edges. They did not support features you would expect such as jumbo frames. From the MikroTik site on the newer revision improvements:
- Jumbo frames up to 10218 Bytes are now supported;
- Link speed reporting is fixed – actual link speed in the interface menu is listed. Previously 100M/1G/2.5G/5G link speeds were not reported correctly;
- DDM monitoring (Supply Voltage, Module temperature) is now supported. (Source: MikroTik)
One item we did not like is that the exterior of the modules does not say Rev 2.16 clearly. Instead, you are likely going to need to check with your reseller or plug them into a switch. Here you can see “Vendor Revision 2.16” via WinBox and one of the modules:
If you are reading this review, it is likely any new S+RJ10 module you will buy is Rev 2.16 or newer. They have been in production for several quarters now. There was a lot of early feedback out there about not having features like jumbo frame support. The Rev 2.16 modules also seem to be more stable from a low quantity observation. If you do see one in the field and are seeing issues, one item on your checklist should be to see if it is a Rev 1.0 module. We would not recommend the Rev 2.16 modules for the heart of switching at the New York Stock Exchange, but if you have an office or even a home setup where you need to connect base-T devices, Rev 2.16 is what you want.
MikroTik S+RJ10 Performance
We ran a few NAS tests to a SFP+ SSD NAS from a workstation with a 2.5/5/10Gbase-T adapter as well as a SFP+ adapter to see the impact of the S+RJ10 running in a MikroTik CRS309-1G-8S+IN switch.
We lost a bit by moving to 10Gbase-T on our test setup, but we saw generally good results in what we think will be a common use case. If you have a SFP+ switch and a 2.5GbE or 5GbE NAS, the S+RJ10 gives you a lot more performance at only $55 or so to connect the NAS.
The MikroTik S+RJ10 we look at as a tool. Putting 8, 16, or 24 of these into a SFP+ switch is not the best use of resources. The MikroTik CRS312-4C+8XG-RM has 12x 10Gbase-T ports at $500 or under $42/ port. Converting a SFP+ port using the S+RJ10 is around $55 plus the switch port. At the same time, if you have an existing switch and need a small number of 2.5/5/10Gbase-T ports, such as 1-3, it can be easier to use the S+RJ10 over adding another switch. This is a case of being a good value in small quantities, but not necessarily large ones.