Slowness after idle - Disabling modem sleep?

[modest]

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

[Jon_T]

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!

[modest]

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.