I've done this before for months at a time (the GL.inet E750 with an iPhone with no SIM) but oftentimes US GSM providers throttle the hell out of UDP traffic on

I've done this before for months at a time (the GL.inet E750 with an iPhone with no SIM) but oftentimes US GSM providers throttle the hell out of UDP traffic on weird ports (like to 64-128kbps, a tenth of a megabit), and also notifications are frequently delayed.