Hello,
when I look in the datasheet of Deciso DEC750 I will find the following limitation:
When using SFP+Modules, do not mix 2.5/5Gbps and 10Gbps link-speed as the hardware does not support mixing these due to different frequencies.
What does it mean exactlty? Can I not use one of the ports for a 1 GBit SFP GPON fiber modem and one port for a 10 GBit SFP+ module to connect to a switch?
You can mix 1 and 10 Gbps, yet the basic operation mode for 2.5 and 5.0 Gbps is different, because those are NBase-T, which use SGMII.
I did not even know that SGMII works with the adapters built into the DEC 750 at all - I once owned one and back then, it did not work with SFP-GPON modules at SGMII speed.
I think that the base operating frequency is different for 1 and 10 Gbps than for the other speeds and that the base frequency is used for both NICs, so you cannot "mix" them over two adapters. You might be able to use 2.5 Gbps on both adapters, though.
Quote from: meyergru on September 23, 2025, 08:28:39 PMI did not even know that SGMII works with the adapters built into the DEC 750 at all - I once owned one and back then, it did not work with SFP-GPON modules at SGMII speed.
Thank you.
It looks like that I have to re-think my complete idea. I am undecide if I go with OPNsense on bare metal or if I will go for a little bit higher spec, run opnSense under Proxmox VE or XCP-ng and use the idle recourses or some small VMs. The devices so far on my comparison list are: Protectli VP2440, Protectli VP6630, Protectli VP6650, Deciso DEC750, Netgate 6100, Netgate 8200. If Intel X710-BM2 has the same limitation it looks like only the Netgate devcies will be left over in my list.
Many of the SFP+-capable NICs only support 1 and 10 Gbps - as I said, I was not even aware thate the one in the DEC750 (ax) has (limited) support. The intermediate speeds of 2.5 and 5.0 Gpbs are mostly supported by PHY adapters that "translate" to 10 Gbps. I would refrain from using SFP adapters for GPON at all and use external ONTs with a 2.5 Gbps ethernet connector (I do that).
Those SFP adapters get very hot and SFP+ for XGSPON do that even more. You can get away with a cheap barebone Aliexpress appliance with I226 adapters if your internet speed does not exceed 2.5 Gbps. I use a baremetal approach for many reasons:
1. To not introduce a single-point of failure in the Proxmox machine. If something goes wrong with that, I would like to keep internet access.
2. For security reasons.
3. Because Opnsense under Promox has its limitations and pitfalls, see this (https://forum.opnsense.org/index.php?topic=44159.0).
Quote from: meyergru on September 23, 2025, 09:25:46 PMappliance with I226 adapters if your internet speed does not exceed 2.5 Gbps
My chinese mini pc has three i226's and two x520's. The mix I thought could be useful to me.
Duly noted, the freeBSD drivers for Intel ports that use SFP's do not directly support non-Intel SFP's, driver source code actually says you can use unsupported SFP's but use at your own risk, and then you have to set the sysctl to enable use of unsupported SFP.
Yes, but especially the X520 does not support 2.5 Gbps at all (i.e., not with SGMII mode). I have them, too, but I only use them for DAC cabling to my switch.
Quote from: meyergru on September 23, 2025, 09:25:46 PMI would refrain from using SFP adapters for GPON at all and use external ONTs with a 2.5 Gbps ethernet connector (I do that).
It looks like this will be the best idea. I thought I could save one device by using a SFP GPON. But going with the mainstream solution of an external device seems to be the best way to go.
Quote1. To not introduce a single-point of failure in the Proxmox machine. If something goes wrong with that, I would like to keep internet access.
Basically this I see in the same way. That's how I started over a decade ago. And that's where I am again today after an excurse up to a full blown server. Today, again I would be willing to do a little compromise.
Quote2. For security reasons.
Yes. I am home user. Using pci passthrough for at least the WAN NIC would give to me enough confidence in security.
Quote3. Because Opnsense under Promox has its limitations and pitfalls, see this (https://forum.opnsense.org/index.php?topic=44159.0).
Proxmox is what I am familiar with. For several reasons my primary choice is XCP-ng for this plan. (Or bare metal)