[BPI-R4 pro] how to customise the board to keep 2 10gbe connectors + extra SFP

Banana Pi Router design
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based on my previous question about GPON networking: Let’s assume I can find a config which actually works for GPON networking. The major problem is: while the GPON SFP module would only have a 1gbe speed (max), it takes one of the 10gbe NICs (and I’d need both). So, what options do I have if I need a SFP cage for GPON networking and 2 10gbe ports? or would the advice be “bury your GPON SFP project, keep the external ethernet->GPON bridge and accept the additional SPOF”?

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For 1 gbps you could use an USB - sfp converter

https://a.aliexpress.com/_EvxjKGk

Hopefully it has a linux driver in mainline… It says it is linux supported.

Or maybe an rj45 to sfp converter like so:

https://a.aliexpress.com/_ExPsa1A

2 Likes
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thank you Eric! this would indeed solve the issue … time to make a list of everything I need then … hopefully it won’t take too long anymore before the R4 pro is available on aliexpress, as I can only pay in €, not $ :slight_smile:

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I think the main difference between the 2 options (usb-sfp or rj45-sfp) is hardware flow offloading. Via usb it cannot be offloaded in hardware. Although at only 1gbps it may not really be a problem for this cpu. Software flow offloading could still be enabled.

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… but if using RJ45-SFP bridge it won’t be manageable, right? Though I have my doubts whether there is anything manageable in the SFP module at all, USB->SFP may still expose some mgmt capabilities

EDIT and it (hopefully) can tell me whether the module is in trouble or not … if using RJ45->SFP there’s no chance

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Maybe you can poll it over telnet…

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concerning supported: according to manufacturer it has a realtek RTL8153B or RTL8213 chip … I’ll check the USB drivers ID of realtek, guess I can find it in there

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do you think those modules have a separate internal IP to poll?

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Never used one before, time to read up in the topic. Some of these things even run openwrt.

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alternative solution: mpcie modules with 2x 2.5gbe do exist (I even got one). is this also the case for 10gbe? and would it be feasible or a horror solution for the 3.3V line?

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The bottleneck would be the single lane PCIe, as the second lane is not at standard pins, even if the 3.3V would hold.

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all right, I didn’t think of that one, but good point indeed! What would introduce the highest latency? I mean, the USB bus might introduce extra latency I do not want for all devices in my home. on the other side, converting RJ45 to SFP and back may even be worse