On Thu, 2015-05-14 at 22:34 +0100, John Whitmore wrote: > On Thu, May 14, 2015 at 03:20:36PM -0500, Dan Williams wrote: > > On Thu, 2015-05-14 at 20:44 +0100, John Whitmore wrote: > > > Chances are that I'm in the wrong place here, "Linux" networking having > > > so many > > > parts, many of which aren't in the kernel, that being said this might be > > > considered the centre of it all, so I thought I'd start here and see if > > > somebody would point me in a direction that was better placed to answer > > > some > > > of my queries. > > > > > > I'm working on a mobile system, RaspberryPi based, which has two 4G USB > > > Dongles for communications to the Internet. Both dongles are the same > > > make and > > > model but have different service provider sims. The idea being that if > > > one has > > > no coverage hopefully the other does have some degree of connectivity. I > > > started by connecting up to the internet using network-manager-gnome for a > > > single dongle. Unfortunately when I started a ping test after a couple of > > > ping > > > messages it crashed the whole raspbian system without any message going to > > > /var/log/messages. Totally locked up. > > > > Odd, are these dongles using AT commands or are they using one of the > > proprietary protocols like QMI, MBIM, or QCDM? It's highly unlikely > > that NetworkManager + ModemManager would be crashing your system when > > using plain AT commands, but there have in the past been driver problems > > with QMI and MBIM. Can you give specifics on the dongles? > > > > Thanks a million for that! I've never played with GSM Dongles before, so I'd > never heard of anything but AT being used. That is a great help. Dongle is a > Huawei E398. It's a LTE/UMTS/GSM Modem/Networkcard according to "lsusb" and > comes in as 12d1:1505 and then after usb_modeswitch 12d1:1506. Given that > "Networkcard" all those protocols you mentioned are probably what's being > used.
I got your mail on ModemManager-devel and responded there too, just a quick follow-up here. So you're actually using a QMI-native device, but using it in PPP mode with wvdial. It looks from your logs like the modem is crashing and dropping off the USB bus. We should try QMI+net to see if that will work better than PPP. > > > Having failed with the Network-manager I used wvdial to establish a > > > connection > > > and that is as happy as larry, pinging away. > > > > Are you using PPP as the mechanism here? Unless you have very low > > bandwidth requirements I'd recommend using the pseudo-ethernet interface > > provided by the modem (which often also requires using a proprietary > > protocol like QMI or MBIM to control it) since this gives much higher > > throughput especially with HSPA+ and LTE. > > > > Yes when I use wvdial it brings them up using a ppp0 interface. I should go > back to the network-manager and keep an eye on the modem manager. Didn't > realise that service was in there so again thanks a million. > > > > My questions are to do with how to manage two identical Dongles. At > > > present > > > when usb-modeswitch ejects them, from CD Drive, into modem configuration, > > > when > > > "qmi_wwan" assignes a network name. I'd like to assign udev rules to > > > assign > > > carrier based names to the network interfaces. I'm not sure if udev will > > > interfere with qmi_wwan? > > > > Aha, so you are using Qualcomm-based dongles :) So NetworkManager + > > ModemManager will natively try to use QMI + ethernet on these dongles > > just like Windows does, because that provides the most flexibility and > > speed. So the crashes/hangs you were experiencing may be due to driver > > issues in the qmi_wwan and cdc_wdm modules. What kernel version are you > > using here too? > > Latest for the RaspberryPi, I think, 3.18.13 on a RPi Vesion 2. It's not what > came with raspbian but I built the latest. Given that you're using ModemManager 0.5 (without QMI) or wvdial, kernel version and driver issues in qmi_wwan or cdc-wdm won't be the cause of the problems here and could be the solution :) Anyway, lets follow up on ModemManager-devel. Thanks! Dan > > > > > That is possibly the easy part. I then want to attach some logic to > > > manage the > > > connections in a very basic manner and perhaps display connectivity > > > information to the user on the desktop. Could somebody tell me where this > > > functionality would be added? I assume that ppp has no idea about GSM > > > signal > > > strength. It'd be great if a simple user space program could monitor DBus > > > and > > > bring up or drop the connections as conditions change, but I guess that > > > might > > > be asking for a little bit much. So if not ppp what sub-system controls > > > the > > > Modem? > > > > It all depends on the modem itself and what it supports. We've tried to > > develop ModemManager as single system service that works with all kinds > > of modems and insulates you from these kind of issues. The end result > > is that nothing in the Linux kernel itself provides this kind of > > management; the kernel only provides interfaces to the modem's firmware > > and its up to userspace to figure out what protocols the modem speaks > > (AT, QMI, MBIM, QCDM, etc) and to talk those protocols to the modem. > > > > Dan > > > > Thanks so much for taking the time to educate me! I have to look into all this > and more protocols then I knew existed. I'll have a look into the modem > manager as that's probably something I've done incorrectly. > > John -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
