Multiple Ethernet ports on the raspberry pi

RE: Multiple Ethernet ports on the raspberry pi

nothankyou — Tue, 06 Mar 2018 20:19:29 GMT

Hilscher has a three port Ethernet product; three standard Ethernet ports or one standard and two Real Time Ethernet ports for Profinet or EtherNet/IP

RE: Multiple Ethernet ports on the raspberry pi

gam3t3ch — Fri, 07 Apr 2017 01:59:41 GMT

I have not tried it but definitely would consider this route. but yes the usb method would work or even just running it through a switch would work as well.

hope this helps

RE: Multiple Ethernet ports on the raspberry pi

industrialberry — Wed, 05 Apr 2017 12:11:02 GMT

Hi Guys, if you are interested on a board with dual additional ethernet interface,

we have developed the EthernetBerryDual.

Best regards

Pierpaolo

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Sat, 14 May 2016 08:12:25 GMT

@enrico - Good article. Good pointer. I did not do the iptables step you have. I guess when I set the interfaces addresses to zero, the bridge handles the switching automatically. Interesting exercise could be to see performance difference between these two approaches since the iptables is another software step/jump. But it may be more "correct" in some ways since it uses the Linux routing infrastructure i.e. in the kernel. I think the difference will be there for large volumes of traffic I think if any. Will try your approach and see too. Performance is an issue due to what I need i.e.bridging across 6 interfaces.

RE: Multiple Ethernet ports on the raspberry pi

balearicdynamics — Sat, 14 May 2016 06:56:10 GMT

Hi Shreesh,

I hope the link to an article I wrote about the Ethernet / Wifi bridging on PI maybe useful for you: Meditech: Creating a Pi Bridge

Enrico

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Sat, 14 May 2016 01:18:16 GMT

FYI: The route option was proving very flaky in the end with multiple Ethernets. It would NOT just work with more than 2 ethernets. Had to be reconfigured everytime and still.

But I did a simple "fix" - I created a bridge on the master controller linking all the required ethernet interfaces and it works everytime properly. So just in case anyone needs this:

sudo apt-get install bridge-utils - for brctl

sudo brctl addbr br0

sudo brctl br0 eth1 eth2 eth3

ifconfig eth1 0.0.0.0

ifconfig eth2 0.0.0.0

sudo ifconfig br0 up

now br0 is the only visible interface and one can use the child pi's to ping the br0 address and it works reliably. Of course this is temporary i.e. it needs to be set up to be persistent across boots in /etc/network/interfaces I think. Will be trying that next. But hopefully this helps anyone else needing this.

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Thu, 12 May 2016 19:49:51 GMT

@john - actually the problem was in trying with more than one USB-Ethernet on a HUB or directly on the pi. I did have a powered USB hub off which the USB ethernet was attached. To make them work one has to configure as Roger mentioned. And am working on a concept/project which is to build up a network of Pi's controlled by a master Pi. Essentially 6 pis controlled by a master pi. So the SPI approach would not work for this many PIs too? I understand the limitation of bandwidth with the USB approach. But it is a POC and we will eventually try and customize the PI I think. There is a space crunch too since it needs to be a compact unit. So will be going to the host transfer cable approach which anyway creates a network interface. But is much more compact. One thing I am not yet sure is with these many host transfer cables the power needs of these "powered" cables will be high and so may need a USB powered hub. If that is so, then I may as well use the USB ethernets. Basically trying to avoid another power plug. I already have one big power source to power all these pis - since the 6 pis have a 7" pi display attached too. Same issue with using an ethernet switch - its expensive, bulky, heavy and needs an external power source[where it will consume gobs of power too] - but may get the maximum performance since its not shared on the Pi - at least not all 6 are shared on a Pi then.

I guess as a POC i want to connect them with the best compact way possible. Essentially need to run graphics off of the main pi. So need a reasonable connection too!

RE: Multiple Ethernet ports on the raspberry pi

Problemchild — Thu, 12 May 2016 14:37:42 GMT

Just use an USB to Ethernet stick via a powered HUB.

Dont expect any particular level of performance of any of the posibble solutions as you are some what constrained on bandwidth on all the methods explained here and previously.

I'm assuming you are trying to learn some networking skills rather than learning how to connect say an SPI ethernet device to the RPI.?!

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Thu, 12 May 2016 05:52:55 GMT

Roger,

That was amazing! It just works now:)

It took me two seconds to type it in though...! But great tip. Now I can return these USB-Ethernet and do it with the host transfer cables directly. Sweet!

Thanks again,

Shreesh

RE: Multiple Ethernet ports on the raspberry pi

rew — Thu, 12 May 2016 04:35:49 GMT

Shreesh The good thing about Linux is that it allows you to debug these problems and work to a solution. You're almost there. What you have determined is that everything works, but that the routing to the "not working pi" is not correct.

If you type:

sudo route add -host <ip-of-not-working-pi> eth<number of the correct interface>

you'll have it working in less than a second. :-)

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Thu, 12 May 2016 03:31:50 GMT

I have a question on this setup - does it work?

Essentially I'm trying to connect two pi's to one pi. So I put a couple of USB-Ethernet adapters on a USB 3.0 hub and connected the hub to the master pi. I always see that only one of the child pi's can ping the master pi. The master pi shows IP addresses for both the Ethernets. And funnily, only the one that is able to ping the master pi can see both interfaces on the master pi i.e. able to ping interfaces - even though only one interface is directly connected to each child pi. . the other child pi seems to have an IP address but is completely blocked off. From running netstat on the master pi, I see an even more funny thing - when the pi that cannot ping the master pi is trying the ping to the master pi - the master PI seems to receive the packets on the right interface - but seems to be responding on the the other Ethernet interface! And so the ping fails!

I tried with a USB host tethering cable and see the same issue - when one more than 1 cable is connected. Has anyone seen this? Some issue with the pi? Some configuration?

Of course, I can use an external switch and connect them up. But thats too bulky/heavy/ugly for my application and ideally I would like to connect them up "internally" like this. Ideally IF I can have a USB-USB network connection.

RE: Multiple Ethernet ports on the raspberry pi

rew — Tue, 13 May 2014 07:22:41 GMT

Sure it can. (be multihomed).

About the performance... I have a 15Mbps ADSL connection. So if one of the ports is limited to 15Mps or if the total is only 115Mbps, that' be fine. In fact, if the raspberry pi is the router, a total of around 30Mbps would suffice.

Leaving the pi on (e.g. powered by the standby 5V power of your PC?) and a few storage devices connected can leave you with a powerful setup. long-term-downloads can continue all day without using much power. The pi might control other stuff, e.g. power on the PC when ordered to do so over the internet. etc. etc.

RE: Multiple Ethernet ports on the raspberry pi

Robert Peter Oakes — Tue, 13 May 2014 02:26:29 GMT

Can the PI not have its Ethernet port multi homed

ie, 2 IP addresses on one port, Windows can and most versions of Unix in the past so even though I have not tried it on the PI, im sure it can be done

this would probably give the fastest Ethernet speeds but you would still need the external Ethernet switch or two cheap hubs working in reverse etc to support it

RE: Multiple Ethernet ports on the raspberry pi

Robert Peter Oakes — Tue, 13 May 2014 02:23:40 GMT

Still limits on the model B, I would add the USB hub no matter what for this

RE: Multiple Ethernet ports on the raspberry pi

Problemchild — Tue, 13 May 2014 00:00:05 GMT

Sorry to say but the performance is going to suck a bit either via SPI or USB, either way you are going to end up sharing buses.

Most SPI Ethernet chips already have drivers but you may have to compile them for the RPI ( Probably still too much hassle!!!)

A novel approach is to maybe use VLANs and a couple of virtual network interfaces on the PI but this requires an infrastructure that supports VLAN tagging etc.

Probably the most obvious is something like the picture below where you get a cheap EBAY USB hub that's powered and bung some cheap USB-Ethernet adapters on it. This one has a DM9601 chipset and I'm sure I've had it on the PI and should work OK if not a quick driver download will sort you out ...Take the easy way out ....Good luck!

RE: Multiple Ethernet ports on the raspberry pi

johnbeetem — Mon, 12 May 2014 20:09:38 GMT

I don't know what the status of RasPi USB is nowadays, but early on there were fairly severe limits on how many USB devices you could attach and still get reliable operation. I believe it was a limitation of the BCM2835 SoC, which has a rather limited USB controller. The BCM2835 is a media processor designed a few USB devices and may not be able to support lots of Ethernet dongles and disk drives. I don't know what RasPi operating systems are able to support today, but I suspect you'd be better off with a SoC that has native Ethernet (instead of through USB) and SATA.

RE: Multiple Ethernet ports on the raspberry pi

mconners — Mon, 12 May 2014 18:53:38 GMT

I agree the powered usb hub with an ethernet adapter would probably be the best solution. Writing an SPI based ethernet device driver would be a challenge. Probably doable, but a challenge nonetheless.

Mike

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Mon, 12 May 2014 18:48:13 GMT

The onboard Ethernet is on the USB bus. It's built into a USB hub chip that connects to the single USB host port on the BCM chip.

You can get USB hubs with built-in Ethernet port. They probably use similar hub chips to the one on the Pi.

There is no super fast data bus on the Pi to connect lots of high bandwith network ports to.

The simplest option is probably to connect up a cheap Ethernet switch.

If you main interest is in configuring your own router / firewall you might be better to get a standard router and put dd-wrt or similar on it. People use these things as internet radios and the like. Plenty of Ethernet ports and a USB host, probably a serial port in there somewhere too.

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Mon, 12 May 2014 18:13:19 GMT

Well, you got me there... Writing a kernel driver is way beyond me current abilities...

Guess I'll be sticking with plan B: the USB adapter.

As for getting a commercial Nas, the actual point is the router/firewall.

RE: Multiple Ethernet ports on the raspberry pi

rew — Mon, 12 May 2014 18:08:01 GMT

Well, you connect it to the SPI pins on the GPIO pins near the TV connector. Then you write a kernel-driver to talk to the chip and you're done!

RE: Multiple Ethernet ports on the raspberry pi

shabaz — Mon, 12 May 2014 18:05:16 GMT

As Mike mentions, it would likely connect to the SPI pins of the RPI header (SPI is a standard, so there is lots of information on it). However, these types of devices have their own stack, so the documentation that you'd also need to consult depends on the particular device you use. It would be a lot of software development effort to do what you're planning to do (NAS and router), and probably you'll be trailblazing so uncharted territory. But feasible.

As Roger suggests, the alternative is to just plug in a USB network adapter. This is almost guaranteed to work if you have drivers and can sort out power considerations, hub, etc (some of this might not be trivial either).

After all that though, I'm not sure it would be worth it. A dedicated NAS may cost about the same, and will perform way better, but I understand people may wish to do it for educational purposes.

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Mon, 12 May 2014 17:54:12 GMT

Sorry, last comment regarding the Wiznet 5100.

As for the hub suggestion I save it for last resort, unless someone can recommend a specific model.

Thanks to both of you for answering

RE: Multiple Ethernet ports on the raspberry pi

Former Member — Mon, 12 May 2014 17:51:56 GMT

How do I go about connecting it to the pi?

Is there any documentation for the pi that I should look at?

RE: Multiple Ethernet ports on the raspberry pi

rew — Mon, 12 May 2014 17:32:14 GMT

I wouldn't recommend that adapter. IIRC that's one that will enable your microcontroller to talk 'ethernet' easily.

Search for usb ethernet on ebay and you'll find sub-$5 modules that perform the task.

When you specify that you need to keep at least two ports free for other stuff, I recommend that you get an USB HUB with a hefty powersupply (2.1A min, 2.5A recommended). Then use one port of the pi to connect to the extra Ethernet port, use the other to connect to the hub. With a bit of luck the pi will power up by being powered from the upstream port from the hub and you'll be left with 4 free ports. Otherwise you need to use one downstream port for powering the 'pi leaving you with only 3 free ports in the hub.

The difficulty lies with the hub. If you by a cheap hub it will have the upstream and all downstream 5V lines connected together, able to be powered from the external powersupply. However, expensive ones may leave the upstream 5V disconnected and the downstream ports currentlimited at about 500mA (too little to power a 'pi). :-(

(As I always buy the cheap stuff, I haven't seen that last possibilty myself. ;-)

RE: Multiple Ethernet ports on the raspberry pi

mconners — Mon, 12 May 2014 17:06:48 GMT

There are modules like this.

https://www.sparkfun.com/products/9473

That is by no means the only one, they are SPI based, so you might be able to do what you want.

Mike