Its oversubscribed as many users share the same link at some point and that link is not big enough to allow all users to use all their bandwidth at the same time. ISPs will oversubscribe and add more capacity when needed to avoid congestion, around 70-95% utilization depending on link size. American ISPs seems to not care as much though.
It's really not interesting to say that a major ISP doesn't have capacity for all of their customers to use their advertised bandwidth at once. That extreme just doesn't happen, and so the cost/benefit of preparing for it just isn't there. Some oversubscription is normal. And when I said typically overprovisioned, I meant relative to actual observed/projected load rather than theoretical worst-case.
For their upstream links to actually be maxed out (thus "experiencing congestion" as Hikikomori put it) with any regularity is more remarkable—suggests they screwed up their capacity planning or just don't care. I kind of expect that from Comcast but not ISPs in general.
For those links to be of varying capacity (like the 5G/Wifi networks the article mentions) would be truly surprising to me.
It's not helpful to say the term oversubscribed if you mean something different than the existing meaning. Just make up your own word for what you mean or use a different word.
> ts oversubscribed as many users share the same link at some point and that link is not big enough to allow all users to use all their bandwidth at the same time.
that's a definition of oversubscription.
> around 70-95% utilization depending on link size.
2/3's with dumb queues, <100% with the computational tradeoff of sqm
