Capacity, not speed — how much can travel at once. It is shared across the whole house, so one large download can starve everything else until it has finished.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
a wide pipe, with everyone drinking from it.
For example
Someone upstairs starts downloading something huge and your movie stops. One pipe, and they took most of it.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.