Comment 9 for bug 798649

It looks like the reason this is not working is because it is only checking for devices at /sys/class/net/blah/device.

The problem is that PPP devices(modems, and mobile broadband) will not show up as this type of device. I think the best thing here would be to not check what type of devices it is. But instead to just check if it can do IPV4 or IPV6. This is what Gnome System Monitor does (load-graph.cpp line 558), and it works with PPP devices.

Here is a branch for trunk that fixes this:
http://bazaar.launchpad.net/~workhorsy/+junk/indicator-multiload/revision/63