Hello Everyone.
I just spent the last few hours diving into this topic. The Reason is I have my house and home lab kitted out with both Mikrotik CRS305's & CRS309's, as the backbone of my House's 10Gb Networking. Up until today, I have only connected 10Gb Clients to my Network (Other than my Army of 1Gb Devices), so I never had to deal with setting up 5Gb or 2.5Gb clients on my Mirotik Switches (which all run SwitchOS).
Well today I finally decided it was time to Upgrade my Engenius Wifi AP's, from Wifi 5 to Wifi 6, and ordered 3x EWS377AP's. These AP's Use a 2.5Gbps Uplink so I then Went and checked in my Transceiver drawer to make sure I had at least 3 of my Ipolex 10GbaseT SFP+ RJ45 modules left, and I only had 2. Then the thought hit me that I should test both the Transceiver and the Mikrotik's ability to handle 2.5Gb Connections before ordering the 3rd, just to make sure that I won't run into issues, and that's what sent me down this rabbit hole.
I already had to deal with Engenius, selling an AP that has a 2.5Gbps uplink without a Power Adapter, and then recommending their Gigabit PoE Injector as the solution
. I was able to find a low cost Injector that had great reviews that supports 2.5Gb and 30w PoE for just $25, only to come across this madness.
I have quite a few 2.5Gb and 5Gb USB3 NIC's that I use while on site at clients, so I know that at least 2 of these USB NIC's handle the Bandwidth with very minimal speed loss, so I plugged the 2.5Gbps USB NIC into my Laptop that I had just used a few nights ago and had gotten just under 260MBps when transferring an ISO from my Laptop to a Client's Server over their 10Gb Network, so I figured as long as I could match that speed when transferring the Same ISO from my laptop to my Server, and Vice Versa, then I will probably be fine when the new AP's arrive.
Unfortunately what happened was pretty consistent with what was happening in this thread. Basically when Transferring from my Laptop using the 2.5Gb USB NIC connected to the Mikrotik Switch over the Ipolex 10Gb SFP+ Transceiver to my Server which is hooked up to the Same Mikrotik Switch using a DAC cable to my Intel 10Gb NIC in my server, I was seeing the speeds I was expecting of about 250MBps, but unfortunately when going the other way from my Server to my Laptop, the Transfer was averaging about 110MBps, sometimes dipping far below Gigabit Speeds. And then When doing Transfers at the same time, one each way, performance would tank even harder. That's when I searched for an option to lock the Transceiver at 2.5Gbps on Google when I couldn't find an option in SwitchOS, and I found this thread, and a few others, including the thread that was linked to in here when a forum member tested this use case with different transceivers. (
https://forums.servethehome.com/ind...t-marvell-88x3300-v-s-aquantia-aqs-107.30004/ )
Anyways, All this is to say that, in this thread it is mentioned a few times that the Aquantia "AOM-AQS-107-B0C2-CX" seems to handle this scenario well thanks to its implementation of Pause Frames that reportedly does a great job of handling 2.5Gbps or 5Gbps in either Direction. The Reason I am chiming in is because those Aquantia Transceivers are incredibly expensive, they are the same Price I paid Per each AP, so I really didn't want to break down and spend another $600 on just making the 2.5Gbps uplink work on each switch, which are at opposite ends of my house, so I would either need to run new cables in the ceiling if I replaced my main backbone CRS309 Switch, or replace each CRS305 Switch with one that can handle 2.5Gbps and 5Gbps seamlessly. A Quick look on Amazon, Newegg, and eBay found that we are not sitting much better now than when I bought the 4 Mikrotik switches in 2020. It seems to be impossible to find a 5 Port Managed 10Gb RJ-45 Switch for less than $500, and even then its usually some weird combination of ports, not something small and straight forward. (I need Managed because my network has several VLAN's, so I can't just buy one of those cheap TPLink options that are unmanaged for this, or I won't be able to Pass the VLAN's to my WiFi.)
So I spent some more time looking, and I found these:
Supermicro AOM-AQS-107-B0C2-CX Compatible 10GBASE-T SFP+ Transceiver | Optcore.net
I have searched and searched the forums to see if anyone has tested these yet with NBase-T speeds to see if they will perform the same as the more expensive original Aquantia/Supermicro AQS 107 that these knock off's are supposed to mimic the behavior of. But they Claim that they behave the same, and there is one review on that site from someone who purchased it who claims it works great at those speeds. So I bought 4. I have no idea how long it will take for them to arrive (The Shipping Estimate was 6 to 8 Days), but as soon as they do Arrive, I am going to hook them up and start testing, and then I will post back here.
My new AP's will be here tomorrow, so I am going to get them mounted and hooked up to my Gigabit Switches in each room for now, so when the Transceivers arrive I can quickly hook up each to its room's respective Mikrotik 10Gb Switch and get to work testing the 4th on my Laptop setup. I will report back here once I do, because if these work as I hope they do, they will be a much lower cost solution to the issue a lot of us are having with our SFP+ Switches on Sub 10Gb Devices, and I would love to be able to say we have a reliable low cost transceiver option for that scenario.
Anyways, thanks for letting me ramble, I hope to report back with good news, but I will shut up for now. Have a great weekend everyone!