Wireless Joint

Hey folks,

There's an interesting phenomenon that I've noticed with all of my LTE modems: If the modem stays completely idle for more than a minute or two, the next usage will be much slower (ping > 200 ms). That slowness is temporary and goes away 1-2 seconds after the next traffic.

I've been hacking around this using scripts to ping every 3 seconds in the background, but this isn't very polite. Is there a better way? Is this configurable on any modem?

Other network interfaces do not have this issue.

Configuration: Sierra Wireless EM7565 + Quectel RM500Q-GL + Dell DW5821e, all connected via powered USB3 hub to RPi4 running Ubuntu. (This device acts as a channel bonding router, hence the 3 active modems. The sleep/slowness question is unrelated to this, though, and can be observed independently.)

modest

In GoldenOrb, under Modem and Connection Profile, the default Ping Interval is set to 10 seconds for connection monitoring. I just set it to ping 1.1.1.1 to see if my link was up. Considering this address most likely receives millions of requests per minute, I doubt they are ever going to notice the additional traffic. I would assume the issue would stem from some kind of power-saving mode in the hardware, and then some handshakes that might happen between the modem and tower after it wakes up. That is just a guess though!

Right on. The ping trick does work; I was just hoping that there might be a quieter way.

I feel less bad about generating traffic for CloudFlare (1.1.1.1) than I do about polluting the radio spectrum with unnecessary beacons. But I suppose that lake is big enough to shamelessly pee in.