OpenWRT on PVE and using LET dongle for WAN6

• Download OpenWRT images (squashfs-combined.img) from https://downloads.openwrt.org/releases/
• De-compress by using, "gzip -d <openwrt-xxx-img.gz>"
• Upload to PVE as iso image
• Follow this page for creating an OpenWRT VM, https://optimus-xs.github.io/posts/install-openwrt-in-pve/
• On PVE web UI, add a network interface for temporary WAN access
• On OpenWRT web UI, update software list
• Install quem-ga so that network info can be shown on PVE web UI
• On PVE UI, add LTE dongle to OpenWRT VM
• On OpenWRT, install usbutis for lsusb. 
  opkg install usbutils 
• On OpenWRT, install minicom. 
  opkg install minicom
• On OpenWRT, install following packages for Huawei LTD dongle 
  opkg install comgt-ncm kmod-usb-net-huawei-cdc-ncm usb-modeswitch
• Check there are ttyUSBx device nodes
• Follow this page to connect to mobile network, https://techship.com/faq/how-to-activate-the-data-connection-for-huawei-cellular-usb-sticks-ms2372-series-using-the-ncm-network-interface-in-linux/
• On openWRT UI, add a new WAN interface by selecting device as "wwan0" and protocol as "dhcp"