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shaunmccloud
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10Gb SFP+ to RJ45 Modules

Mon Feb 10, 2025 1:21 am

Hello, I have two CRS328-24P-4S+ running SwOS 2.17 at home (I run RouterOS at work, want something easier at home). I will put two Wiitek 10Gb SFP+ to RJ45 Modules in one for an LACP connection to my home server at 2.5Gbps for each link. I tried using my existing 1Gbps adapters but they did not link up at all right now. Is there a way to force the SFP+ ports to link at a specific speed like there is in RouterOS? I can see the 1Gbps modules under SFP info, but no link at all.
 
guipoletto
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Re: 10Gb SFP+ to RJ45 Modules

Mon Feb 10, 2025 5:20 am

This might help:

https://help.mikrotik.com/docs/spaces/R ... patibility

multi-rate SFP to RJ45 modules are highly non-standard affairs, as there is no standardized way for the SFP-host device (CCR/CRS) to negotiate rates with the remote ethernet-device
the PHY rate will be negotiated by the adapter/module with the remote ethernet-device
and the GMII (SFP) rate will be negotiated between the module and the host-device

there are two different links that have to be negotiated(three if the remote device also uses adapter modules), and no way to guarantee interoperability in all scenarios (especially with multi-rate adapters)
 
shaunmccloud
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Re: 10Gb SFP+ to RJ45 Modules

Mon Feb 10, 2025 7:53 am

This might help:

https://help.mikrotik.com/docs/spaces/R ... patibility

multi-rate SFP to RJ45 modules are highly non-standard affairs, as there is no standardized way for the SFP-host device (CCR/CRS) to negotiate rates with the remote ethernet-device
the PHY rate will be negotiated by the adapter/module with the remote ethernet-device
and the GMII (SFP) rate will be negotiated between the module and the host-device

there are two different links that have to be negotiated(three if the remote device also uses adapter modules), and no way to guarantee interoperability in all scenarios (especially with multi-rate adapters)
The motherboard in my server has native 2.5G Base-T NICs (I226-LM), so no modules on that side. In theory, the modules I have on the way should work, and research agrees with that. I'm just used to the RouterOS side where you can force a link speed.
 
guipoletto
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Re: 10Gb SFP+ to RJ45 Modules

Mon Feb 10, 2025 9:31 am

As discussed here:

viewtopic.php?p=1121064

the "rate negotiation dance" between {module<>remote device}, and between {host<>module} can be a bit complicated, and far from "as easy as forcing a link-speed"