Radxa network equipment - USB/Eth switch

I’m not sure if this is right place, but I’m looking for some information/maybe inspiration.

Recently on several videos about Pi5 I noticed that there is high demand for 2.5G ethernet for pi5. There is only one pcie 3.0 lane so usually 2.5G ethernet needs one of usb ports. Upcoming Raspberry CM5 may change this and provide more pcie instead this north bridge, but for now usually pi5 are connected with usb3 dongles, cheap, easy solution. There are some HATs with 2.5G, some with 2.5G + nvme via switch chip, recently geekworm released top board with nvme + usb 2.5G.

Some time ago there was something like cluster hat, it connects few zero sized boards via usb and allows them to use usb as ethernet gadgets. Of course those had no real ethernet ports so there was no way to do that without that. I’m thinking about such thing for any USB board.

I found this device: https://www.digi.com/products/models/aw08-g300

I’m not sure if this will work as I expect, and I’m expecting to connect sbc, like radxa zero or pi5 and get same thing like 2.5g usb dongle. Maybe poe via usb-pd is also possible. This device cost about 1.5k€ (and it’s industrial grade)
Have anybody seen such project? Is this possible via usb-gadgets? Maybe @radxa team is interested in such thing? Basically same thing as 8x dongles + 8 port 2.5G switch + sfp+/10g eth (for 10G uplink) + or course cables and for pd boards additional power. I think that same thing can be fitted in one, small case.

What do You think? :slight_smile:

It should be more compact than

This is something I considered in my free time, but ultimately I thought it is too niche. For a ZERO sized cluster I’m fine with some compromise, but at 2.5GbE I’d rather have some thing real.

Few years ago high end laptops had port replicators, it just covers computer ports and extends them on desk to connect computer via one special cable to get everything that was needed - power, network (ethernet), peripherals and displays. Later we got thunderbolt docks, that can do everything from that list, uses usb-c port. Now even on some big, heavy workstation laptops You will not get ethernet port, because this should be in dock. Instead of that they include 2.5G usb dongle. Probably sooner or later they will remove hdmi/dp and include yet another dongle and promote wireless displays, just like we got with ethernet/wifi. The conclusion is that customer does not care if he got some functionality via ethernet or usb just like hdmi/usb. Ethernet still is better at long range and we have everything that is needed to network whole building, but at endpoint there are usb devices and so far there is nothing that can act like bigger USB switch.

I would like to keep my ethernet/fiber connection at desk, but on that desk USB only connection would be great. IF such switch could power smartphones, tablets, sbcs and maybe smaller computer then this would very interesting option.

Obviously this could be used for sbc clusters and cluster hat was the only example:

Today 2.5G is a must, if it’s possible to do that with usb pd then such device could connect smartphone charge it and provide with network for backup. Same for SBC’s, tablets :slight_smile: Milk-v just released it’s own switch with SFP+, maybe there are some new possibilities for such device from radxa :smiley:

Is there any way to do that without ethernet chip in between? For now using dongle will convert usb to ethernet and then eth switch is needed, eth port on outside. Is there a way to connect to usb hub, act like ethernet and via dongle to outside? Is this somheo possible via esb gadgets mode?

The device must support USB 3.0 OTG which is not very common on Rockchip devices. We have an upcoming ROCK 2A which uses RK3528A and support such connection, but I’m not sure if it can actually provide the USB 3.0 performance.

Is USB OTG just single port or can this be multiplied somehow? For usb-c/ethernet switch there is need for several such ports to connect more devices and ethernet/sfp+ on output.

yet another thing is power, there are some adapters with both - 2.5G ethernet and usb-c PD, this is something to consider, this will allow to connect sbc with just one cable and have both ethernet and pd. Same as POE but without need for HAT and POE switch. Of course this would require same energy to power everything but may be just more power efficient than usual POE setup. USB-C has already everything that is needed and there are plenty of multi port devices providing only energy.

When using as the device mode then it is a single endpoint. However, you can attach multiple functions to it, akin to have a software USB hub. It’s the same idea with those mouse & keyboard wireless receiver. They will list 2 HID devices on the system while being a single endpoint.

On our system right now you can have both adbd and usbnet enabled on the same OTG port.

As I expected then only single usb-ethernet is possible :frowning: I would make much more sense if there is more usb/ethernet ports available, at least four, eight would be awesome. Is there anything that can be connected via usb/pcie lanes that makes more of otg ports?
Can OTG be configured to power up device? There are some usb-ethernet 2.5G dongles with option to pass power to device, is this possible here?

Something like this: https://www.asmedia.com.tw/products-list/d8cyq6FXzaUH8XJa/C5cYq34qpByQ6jm6

Usually the expectation is for the host to provide power. To allow the device to provide power USB PD must be implemented.

I could find only nvme to usb devices with this chip, so connected to pc via 10G usb and m.2 on other end. Also there are m.2 cards, probably with something similar that give one 10G usb port. But I assume we still cant connect any usb hub there because there will be no otg on each port?

And of course there are 2.5G dongles with power already, first google pick for $35:

And for now perfect usb-c as ethernet 2.5G device will have:

  • 6x such 2.5G dongles with implemented power port
  • 1x ethernet switch with 6 port 2.5G (extra one or two sfp+ for 10G uplink, maybe extra 2.5G ports)
  • 1x usb power adapter to get 6x usb-c power ports for all dongles (maybe extra port for switch)
  • 6x usb-c cables to connect power to dongles
  • 6x short ethernet 2.5G cables to connect dongles to switch
  • that sticking cable from dongle is short, it probably needs to be transformed into female usb and yet another set of 6x usb cables.

I’ve seen such build with zero sized boards (and 1G speed), while all boards were connected via one cable, everything splits into huge cable spaghetti right after those destroying whole set size.

I’m sure that it can be one, small box, something like the one from first post. If somebody will get rid of all cases, solder right end ports and remove those that can be just hardwired then it should be much smaller. Nobody cares today if there is need to connect usb or ethernet to get wired network access, all dock stations are using usb now and include those and much more.