erm
what gives you more right to the internet bandwidth than her?
the router doesn't discriminate unless you set it to, which i
assume you haven't
in that case, she's not hogging the bandwidth per se. She's just
using what you're not.
Imagine a queue for bandwidth access. You have already stated your
rights are equal, so you obviously should not be allowed to cut
queue. Your sis has her computer constantly queuing up for
bandwidth the moment she is done with a file. You only queue when
you want to surf/play games. As a result, she has more "people"
queuing up for her, thus her increased bandwidth spending
power.
Let's compare this to a school canteen. Say class A has 40 ppl and
class B has 5.
The students line up to the only canteen food stall open, and when
a student has finished ordering, he lines up again at the back of
the queue to buy more food. You'll find that the total food
obtained by class A will always be more than class B, obviously.
But there's nothing unfair about it.
So really, she has done nothing wrong(apart from the possible
copyright issues). In fact, she's maximizing your family's return
on investment on the subscription of your internet access. You are
proposing a artificial barrier to entry to the access of shared
resources, which is always inefficient, if not downright
unfair.
But all that is redundant because it's always about looking out for
yourself, isn't it?