Hi there,

I must apologize immediately for the title and the panicky situation I'm currently in. I need to deploy this tomorrow and have run into issues that has me spooked about the future reliability. I'm using two Raspberry Pi's with Debian Jessie in a remote location (really remote or at least hard to get to). The Server Pi has two ethernet, one built in ethernet and oneusb ethernet. It also has a 3G modem.

I need to be able to have all ethernet and ppp devices be able to talk with other. I have an IP camera attached to eth0 and a second single purpose Pi connected to eth1. The second Pi is used simply as a display terminal and displays a web page served from the first Pi showing various sensor data and statistics.

The 3G modem allows me to autossh in and perform sys admin stuff once in a while on the server Pi.

I had all of this working using bridge-utils but it seems (at least from what little I can see in my syslog) that the usb ethernet device is dropping which ultimately brings down the bridge which is a major problem for me.

I've thought about scripting a watchdog to check the network health and performing a reboot but this is awkward and creates some unwanted downtime on my Pi's.

Ideally I want eth0 and eth1 to have static IP addresses. I want them to be independent but yet talk with each other or see each other on the network.

Instead of using bridge-utils can I use iptables and routing?

I really appreciate any help with this and will gladly pay if need be to get a good working solution.

I can not offer to much insight on the inner workings of a Pi..

What are the models of your Pi's? Is the power supply sufficient to power the Pi and the USB devices? Have you verified the 3G MODEM and the ethernet adapter are not overloading the USB current? With the B+ models you can increase USB power from 600mA to 1.2A.

I suppose being in a remote location you might not be able to afford the current requirements of a switch to eliminate the need for the USB ethernet adapter. You could set up iptables to forward traffic from eth0 to eth1 instead of bridging.

There is lots of power and I have the PI set with it being able to handle 2 amps. I think this is an issue with the usb ethernet port itself. I'm currently gong to setup a ping pong situation between the two Pi's. If they don't respond then I'll restart the network.

Prior to the RPI's I was using an Odroid which is a little more powerful but was having very problematic usb driver issues with the kernel. I don't think they have it resolved yet.

I guess I'll stick with bridge-utils and do a network check until I have it properly worked out and then make a trip to the installation.

The only other issue that I can think of is I/O. All USB and ethernet traffic go through the USB controller. Does this happen randomly or can you tie it to a specific moment when you where trying to communicate on all three at the same time?

I was wrong. I measured voltage on the pins of the Pi and its more like 4.75 volts and going to 4.6. I've managed to shore things up a little by moving devices around and am back to 4.89 volts. Still, I'd like to see 5V bang on in a perfect world.

Thanks for your feedback. I thought power was not an issue but I think you got it right in your first response.