throughput or rate control

[hong zhang]

List,

I have a throughput rate question.

How does service provider assign download/upload rate to user such as
download rate 125K? How does ISP control it?

Wifi driver has rate control mechnism but it just try to hit as high as possible rate for the driver. 

Can user really set rate to driver through "iwconfig rate ..."?
I never try it.

Any idea?

---henry