https://ibb.co/fxzkr3v
https://ibb.co/jwjzJmz
Sorry for horrible image quality... I wanted to buy a rPi4 and use a ue300 to connect it to my modem. Then I realized the connector was not RJ45. What is the name of this connector? And is there an equivalent to the ue300 but for this weird connector to usb 3.0/3.1. I want an adapter that is guaranteed to function as good or better than the ue300 with this connector.
Thank you!
Did a bit of googling... Turns out it’s a sfp/sfp+ connector. The problem is, everywhere I checked, Sfp+ (in) to usb 3.0 are 200+ euros... Kind of crazy when you compare it to the ue300 (rj45 to usb) which is 15 euros... haha... price hoarding maybe? I have no idea. Maybe I should just buy a new modem as well. I did hear the sfp+ cables were cheaper to produce and could hold much higher bandwidth though. Weird.
Not very optimal, might be able to get an 1x PCIe SFP NIC and rig it in:
The question is whether it is really SFP (up to 1 gigabit) or SFP+ (up to 10 gigabits). What exact ISP/modem are we talking about? Regular SFP to USB are quite cheap (e.g. below USD 30 for AX88772C based ones and around USD 40 for RTL8153 based ones on AliExpress). Whereas SFP+ are more pricy with the cheapest option being an SFP+ to 10GBASE-T (e.g. below USD 75 on AliExpress). But then you would need a router that could actually handle 10 gigabits 
.
Can you describe the topology here? what plugs into what?
ISP data comes in as what? Fiber? It plugs into what? (i'd have imagined that the SFP port would be for putting a fiber transciever where the fiber plugs...
maybe give us some more higher quality pics of the entire device, showing what inputs and outputs it has.
ISP data comes in as fiber. The fiber cable then plugs into the modem. The modem has a non-modular wire coming out of it with a sfp(+?) header. The sfp header would need to be plugged in somewhere on the rPi4 or into a usb 3.0 to sfp-in adapter. The sfp connector is just there to replace the usual rj45 wire that goes from modem to router. Except as it is non modular, the other end of the wire doesn’t plug into the modem, it is a part of the modem... Otherwise I would have just gotten the rPi4 and switched out the spf for an rj45 I will try to get some higher quality images of the entire setup ASAP.
I am with a french ISP called free. The model of the modem is F-MDCONU2A 0-LR . The model of the router is F-GW05LD 0-LR .
Mmmh, you could buy a Pi4B compute module and the matching IO board that contains an PCIe slot. Then one on the network cards that accept SFP or SFP+ modules might work, But make sure you check compatibility with OpenWrt first.
That said, free seems to be one of the ISPs that is reasonably clueful, so maybe you can configure their modem-router to act in bridge mode and connect the Pi simply via ethernet?
I did see a setting for bridge mod when I looked through their firmware earlier. As I have already stated, the isp router seems to only be able to handle up too 700 mbps goodput (I think someone called it that)... Would this cause any problems. Also if I had the choice between just the raspberry pi 4 vs rpi4 and isp router in bridge mode, which would be better for throughput, internet latency, etc... Because if it comes down to it, I can always buy a new modem as well...
At this point, x86_64 with SFP+/ 10 GBit/s ethernet might actually make more sense, more flexible, barely more expensive and idle power consumption doesn't need to be worse (if well selected); only size would be worse (size, performance, price - you can only pick two).
The one-legged alternative (SFP+ switch and one 10 GBit/s link to the x86_64 router) might be attractive as well.
What is an x86_64 router? Could you possibly link a post, video, or a device on amazon related to this?
Any (ideally low idle power) x86_64 computer with an SFP+ 10 GBit/s card used as a router (uATX is unattractive, but cheap and easy).
Good! That means you do not necessarily need to deal with SFP cages (unless you want to ;)).
Goodput is the net speed your applications will see. And on-line speedtests report typically the TCP payload throughput aka the goodput. Just as reference 1Gbps ethernet has a goodput of around 940 Mbps (you can calculate more precise numbers if needs be, but 940 is a nice ballpark figure).
Routing/firewalling often is more performance-devouring than plain bridging, so if the router delivers 700 Mbps goodput in router mode it might be able to bridge at a higher rate (but that is not guaranteed, so you would need to test that).
A competent bridge will add a few dozen/hundreds of Microseconds at worst 1 millisecond (but that would already be atrocious), sure without that bridge you could save that latency, but in the grand scheme of things IMHO unless the bridge is terribly implemented both options will perform equally well.
Sure, but why do that unless it offers any meaningful advantage over keeping that modem you already have?
And yes, the rpi4B is a nice device for up to 1Gbps speeds, especially given its price, but x86_64 solutions will allow for even higher speeds and still sallow traffic shaping.
Another option worth studying is bypassing the modem entirely, with your own GPON.
I finally managed to find sfp in to usb connectors on aliexpress (they still cost around 50 euros though) that aren’t a 200-300 euros like on amazon... Only problem is the legitimacy of the devices. I think finding a good/cheap sfp to usb connector would be better than running in bridge mode for me.
Thank you; I will look into this.
Do you have any specific recommendations?
I think this might leave me with a similar issue of finding a fiber optic cable (IN) to usb adapter...
Why? The thing is, you can try bridge-mode almost immediately with having to buy much equipment, if if works well, you are done, if not you can still escalate the issue and buy more equipment 
USB even USB3 typically is not latency optimized, so I am not sure whether connecting an SFB-module via USB3 is really that attractive. But then, your network, your rules. it is just I tend to do such things step by step and stop when the achieved solution feels good enough, but that is subjective and by no means better (or worse) than designing the "best" solution on first principles and then go an implement that.
I am not aware of any direct fiber to USB converters. I guess it is just industry-standard to abstract the actual transceiver part into an SFP or SFP+ module. Unfortunately, good OpenWrt routers with SFP slots are rather scarce, even more though if you expect wire-speed aka 1-gigabit firewall/NAT and possibly even SQM performance. This might only be achievable with special hardware-accelerated network engines aka HWNAT or the like. Possible candidates might be Ubiquiti EdgeRouter X SFP or MikroTik RB2011 or RB3011 (with the later only having experimental OpenWrt support). Not sure whether the RPi can actually even do wire-speed 1-gigabit firewall, NAT and SQM.
BTW: Concerning cheap USB to SFP adapters like I mentioned before I don't think it will cost much more than EUR 35: