Rate limiting ports is done through flow-control. This is enherent in the
very nature of ethernet. Has to be otherwise you'd never be able to move
data through the network which each link is operating at a different speed.
TCP-IP is quite effective in this manner at handling not only flow-control,
but packet loss and resends. Spilling bits all over the floor should rarely
happen with TCP-IP traffic. However, other types of traffic (such as voice
and video which are designed to not be recoverable) will spill out. Bits
everywhere! That's why we have brooms in our data centers and telecom
rooms. We've got to sweep the bits up almost every day. Fortunately, they
are recyclable. We box them all up, load them in shipping containers and
send them to China where they are turned into iPads and iPhones.
Brian's connection woes have a very easy explanation, which will most
certainly reveal itself on January 4. He has a 10GB data cap per month. The
son, if I recall correctly, is a gamer. A few hours of on-line gaming a day
and a handful of streamed movies will blow this limit very easily. Oh, and
file-sharing, like Bit-Torrent. In your router, you can block certain types
of traffic and in most cases even apply time-of-day access. Lot's of tricks
of the trade to prevent blowing the limits.
Statistically speaking, people use about 5% of their available bandwidth
while they are on-line. In Brian's case, there are three people using one
shared high-speed connection. If you figure the man-hours on-line in that
household is ten hours per day, and at 5% utilization, you can see how the
cap is hit.
10 GB translates to 333 MB per day. 10 man hours means 33 MB per hour. 550
KB per minute. About 10 KB per second. Translating this to bits, that's 80
Kbps. At my 20:1 usage ratio, this would be a typical usage pattern for
someone with a 1.5 Mbps connection. 1.5Mbps is what most providers average
on a per customer basis, regardless of the sold bandwidth. You can burst
much higher, but sustained rates through the Internet rarely exceed this.
AG
--
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