Method to keep Wireless Modem on-line

[gazmac52]

This may be helpful to others so I am posting my method to keep my wireless modem on-line.
My modem is configured as a failover device if the main link goes down but sometimes it goes off-line and I don't notice. Here is how I keep it on-line. There will be other ways I am sure.
In the root folder create a script called reset_wireless_modem.sh
Here is my script:

#!/bin/sh

LOGFILE=/root/wireless_modem.log
ifaddress=$(/sbin/ifconfig ppp0 | grep "inet " | cut -d ' ' -f 2 )

while [ "$ifaddress" == "" ]
do
  /usr/sbin/usbconfig reset >/dev/null 2>&1
  ifaddress=$(/sbin/ifconfig ppp0 | grep "inet " | cut -d ' ' -f 2 )
  if [ "$ifaddress" != "" ]
  then
    echo date +%Y-%m-%d.%H:%M:%S "Wireless Modem Restarted on $ifaddress" >> $LOGFILE
  fi
done

Make the script executable.
Install the Cron package and add a job:
*/2 * * * * root /root/reset_wireless_modem.sh

That's all there is to it. You may have to change ppp0 to ppp1 etc depending on your setup.
The script checks for a valid connection every 2 minutes and resets USB devices if it is not valid.
This will reset other devices you may have on USB as well so script changes may be required. I only have the LTE modem on USB.
Testing. At the prompt:
Get your device info, enter: usbconfig
Mine returns:
ugen0.2: <sierra wireless,="" incorporated="" aircard="" 320u="">at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (500mA)
Turn modem off, for me: usbconfig -u 0 -a 2 power_off
You may need to modify -u X and -a X for your installation as per the ugenX.X
Monitor the log while waiting for the cron job to run the script: clog -f /var/log/system.log
The wireless modem should come back on-line within 2 minutes.</sierra>