[zanny]

Speed of light is really fast. Once you have something on a wire traveling close to it, you are in pretty good shape time wise.

The number on a round trip is actually kind of incorrect, because the number of routing stations it must traverse will dramatically impact the round trip time, so it isn't just a fixed value. It is a good ballpark though. I think the real impressive thing is how ethernet hardware has been designed well enough to be able to process billions of packets per second where they have to read the IP destination header, compute the next node in the transaction, and send it off. You can often end up doing that a half dozen times in relatively small trips but the individual time commitments are so much smaller than disk IO :P