I have some background in wifi deployment in the WISP space and while I'm sure LTE and other cell-centric technologies are much more complex, a lesson learned in the WISP world is that throttling people can have all sorts of unintended consequences. The goal in most wireless engineering where only one station is allowed to "speak" at a time and the base can only speak to one client at a time (think the old days of ethernet before switching was a thing), and I have to assume cellular is no different in this regard, is to have each client "speak" for as short a time as possible, which allows one to maximize throughput on a single base radio. As you can imagine, if you are throttling somewhere away from the radio pair, you're basically just minimizing throughput for everyone, as your throttled clients hog more airtime.
I would love to one day find out how "throttling" happens in the MVNO case, because the simple/obvious ways of doing this are awful.
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