For a project I need to be able to switch max 8 ports at 1Gbps or 2.5Gbps and connect the switch to to two 1OG routers.
I am tempted to reuse the CRS317 with an RJ45 SFP module, but would it requires to have empty SFP+ slot between connections? Is this better in such case to use a CRS312-4C+8XG-RM ?
Routing or Switching ?
If switching
How about the CSS610-8G-2S+IN ?
It has 8x 1Gbits and 2x 10Gbits
The only disadvantage is the Swoslite
Another downside to the CSS610 is that it won’t be available again until March 2022.
Supply chains are really a problem.
https://www.eurodk.de/de/products/crs/cloud-smart-switch-610-8g-2s-in
However, the outdoor version is available, as of today.
https://www.eurodk.de/de/products/crs/cloud-smart-switch-610-1gi-7r-2s-out
I meant switching sorry (i fixed it). CSS610 is only 1G though, isn’t it?
If you need 10 up to 10G ports then the CRS317 would be the best fit if you plan on using some 1G only SFP adapters or if you are going to use SFP+ DACs for some connections.
@benoitc you forgot the Title, it still says “Routing” =)
May i ask why you want / need 2.5 Gbps for your Project?
do i need to let space with only 1G S-RJ01 ? i only plane to usr with sf0++ fiber and dac
fixed thanks 
as for 2.5G i am not sure i will have a usage for it. but I see some hardware coming with 2.5G porte now like QNAP NAS so best to prepare a little for it.
All SFP-Modules with RJ45 get quite hot.
But I have a couple of S-RJ01 running side-by-side without any problems.
Mikrotik doesn’t really have any 2.5Gbits Switches…
a friend of mine bought the QNAP QSW-2104-2S Switch
to connect some 2.5Gbits Devices and he is very pleased with it !
well the CRS 10G RJ45 and SFP+ models are able to handle 2.5G using the appropriate receiver for the SFP+ models. But yes I agree qnap do interresting things..