2011/4/12 Dave Smith <[email protected]> > On Apr 11, 2011, at 2:13 PM, Andrew McNabb wrote: > > > Certainly there is at least _some_ correlation between distance and > > packet latency. After all, there is no way [that I am aware of] that a > > packet traveling 1000 miles could arrive faster than the time it takes > light to > > travel 1000 miles. > > While what you say is likely true, I was proposing that there is no > *appreciable* correlation between distance and packet latency, when there > are multiple routers involved, because the router induced latency is so much > greater than the latency induced by wire propagation delay. > > I based this assertion on the fact that a router will add a *lot* more > latency than a run of copper wire, even a very long run of switched copper > wire[1]. Although I'm convincing myself as I write this now that a slow, > switched network could add a lot of latency on its own too... > > Given the fact that this was the mid-90s, it seems a bit more plausible. > Back then, big nodes like universities had a lot fewer hops between them. > > Ah, those were the good old days, before the spammers. And MySpace. If only > I weren't so dumb back then -- I would have recorded latency measurements > between my publicly routable IP address in my *dorm room* and other > universities. > > --Dave > > [1] I'm waving my hands and not offering numbers. Suck it up. > -------------------- >
And when it comes down to it, the author of the story said in the FAQ that not all of the points were 500 miles away. It seems that there was a number of nearer points, which would have stopped sooner due to more routing. The farthest possible points were at a radius of 500 miles, which would probably have happened on routes with the fewest hops. I guess after noticing maybe 5 points out of 20 that got to 500 miles, with 15 inside of 500, the conclusion that "no email can go farther than 500 miles" is a pretty decent conclusion to come to.
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