North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: ATM (was Re: too many routes)
Richard Irving wrote: > Light can travel around the world 8 times in 1 second. This means it > can travel > once around the world (full trip) in ~ 120 ms. Milliseconds, not > micro.... You've got faster light than anybody else. The speed of light is about 300000 km/s _in vacuum_; that gives 134 ms arond the planet's equator. > So, why does one trip across North america take 70ms... a) light is slower in dense media b) fibers are not laid out in straight lines (in fact, i saw a circuit going from Seattle to Vancouver via Fort Worth :) 70 ms RTT = 35 ms one way. Given that U.S. is about 50 deg. wide, it is abput 0.7ms/degree; or 250 ms around the world. Less than 2 times slower than light in vacuum. > Hint, it is not the speed of light. Time is incurred encoding, > decoding, and routing. Hint: have a look at a telco's fiber map before spreading nonsense. --vadim
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