Exactly – this is both easier to implement and has the advantage of not incentivizing people to use something like a VPN to get more bandwidth at the expense of everyone else.

Per user limits are not easy to implement, maybe easier to visualize - consider that there are a bunch of packet gateways sitting behind a load balancer and each HTTP session may end up on a different server. There is no entity that counts the live bandwidth usage on a per user basis, let alone control it. Billing and metering is done on a session basis through logs. So from T-Mo's point of view it is much easier to detect a HTTP session as video and just throttle that session.

It is very easy to implement this (I have worked on such a limiter before). You pick the point of entry into your network (wi-fi connection, ISP connection), keep packet and byte counts for every such point of entry, and limit them.

ISPs have it especially easy, because they can be assured of being able to distinguish traffic from a given user (hardware control of the medium). It's a bit harder in wireless scenarios, since the client can spoof multiple different IDs, but it's hard for them to keep open a TCP connection under those conditions.

Eh? Even cheap home routers these days allow you to set QoS rules per device. Have I misunderstood something?

Just because your cheap home router does it doesn't mean it scales to thousands of users on one router. Some home routers are actually quite capable AND very unsaturated. I'm not trying to defend carriers but it is a very apples to oranges comparison.

We did that on low-end PC hardware 15 years ago for conference and guest networks (800+ simultaneous active users, LAN and WiFi).

I find it unlikely that Linux, FreeBSD have gotten less efficient since then and the hardware has made enormous improvements, far in advance of the common uplink speed.

Are there thousands of people on a single flight?

And you thought legroom was bad now....

Per-user limits is certainly way easier to implement than deploying a cluster of proxies doing on-the-fly transcoding of video streams(!)

My university limits my bandwidth to 20mbps for HTTP/HTTPS and lower for SSH. Are they in a different position to normal ISPs?

Really? T-Mobile should know your mac address and ip and be able to rate limit based on that.

Let's say there are only 2 users using it. Then a lot of bandwidth would go unused if each user has a hard cap.

Ideally, there would be a dynamic limit based on network utilization and type of content consumed.

Don't think hard cap. Think avail bandwidth/num of users.

The auto-adjustment is a problem for fast but traffic limited connections because it detects that the connection is fast, then it switches to HD or even 4K and the traffic limit gets used up faster even if the user don't need the better quality stream.

Not sure about other services but at least GoGo was limited to about 500kbps per user last I heard.

> Why not limit the bandwidth per user instead?

Because that would require actual effort from ISPs, which would be in conflict with their current business practice that can be summarized as "to us, you are all equally worthless".