<html> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> On 9/02/2016 9:08 AM, Dan Williams wrote: <blockquote cite="mid:1454969282.23302.0.camel@redhat.com" type="cite"> <pre wrap="">On Tue, 2016-02-09 at 07:31 +1100, Brendan Simon (eTRIX) wrote: </pre> <blockquote type="cite"> <pre wrap="">I have a number or remotely deployed arm embedded linux systems that uses a 3G modem via USB to post http information once per second. The modem goes down from time to time. One reason is we assert the power reset line on the modem once a day (as I've been told that the modems need to be reset periodically, otherwise functionality degrades or eventually lost). The other reasons I am not sure of (service provider initiated? bugs in the application code? The modem can be off for many hours before eventually reconnecting (possibly by watchdog reboot) which is not acceptable for our real -time monitoring application. Does MM automatically try to re-establish a connection if it sees the connection go down, or the modem is reset? Are there recommended or suggested MM settings such that MM will continually try to reconnect if the modem goes down then back up? </pre> </blockquote> <pre wrap=""> This is left up to the connection manager that controls ModemManager and tells it to connect. So whatever you're using to tell ModemManager to start the data connection, that's the thing that would monitor for the modem being disconnected and periodically restart the data connection.</pre> </blockquote> I created a NetworkManager broadband connection in a Debian virtual machine with a modem connected (dev kit). I then copied the file that was created (/etc/NetworkManager/system-connections/telstra-mobile-broadband-1) into my build system which will populate my target rootfs for the embedded system. I found that the modem was not coming up at boot, but would come up if I used the `nmtui-connect` utility to activate the connection. A systemd service was created to bring up the modem at boot time (a one-shot script, which brings the modem down then up then calls `nmcli d connect cdc-wdm0`). The scirpt works but I'm not sure if it's the `right way` to get the modem up automatically. One interesting thing which may be a clue is that the modem connection does not appear in the `nmtui-edit` utility, but does appear in the `nmtui-connect` utility. Is this expected ? Also the LAN connection shows up in both utilities but there a connection file does not exist in /etc/NetworkManager/system-connections/ I presume NetworkManager is starting and managing the connection, yes? How do I get it to auto-reconnect when the connection goes down or is not available? We are looking at running a custom script invoked via cron every minute, but that seems a bit hacky. The system connection file is as follows <blockquote><tt>[connection]</tt><tt> </tt><tt>id=telstra-mobile-broadband-1</tt><tt> </tt><tt>uuid=ade7c9ec-26ad-4981-86b4-c2fc6fc4d200</tt><tt> </tt><tt>type=gsm</tt><tt> </tt><tt>permissions=user:root:;</tt><tt> </tt><tt>autoconnect=true</tt><tt> </tt><tt> </tt><tt>[gsm]</tt><tt> </tt><tt>number=*99#</tt><tt> </tt><tt>password-flags=1</tt><tt> </tt><tt>apn=telstra.extranet</tt><tt> </tt><tt> </tt><tt>[ipv4]</tt><tt> </tt><tt>method=auto</tt><tt> </tt><tt> </tt><tt>[serial]</tt><tt> </tt><tt>baud=115200</tt> </blockquote> Thanks, Brendan. </body> </html>