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Examples for the speed of light

Examples for the speed of light

Posted Aug 10, 2012 0:28 UTC (Fri) by paulproteus (subscriber, #69280)
Parent article: TCP Fast Open: expediting web services

The article says:

At intercontinental distances, this physical limitation means thatâ€”leaving aside router latenciesâ€”transmission through the medium alone requires several milliseconds
To be more concrete:
• 1 mile is 5 microseconds
• 6 milliseconds from New York to Florida (1152 miles)
• 15 milliseconds from New York to San Francisco (2917 miles)
• 36 milliseconds from New York to Tokyo (6735 miles)
Source for time conversion: GNU Units.
You have: 1 mile
You want: light second
* 5.3681938e-06
/ 186282.4

Examples for the speed of light

Posted Aug 10, 2012 1:27 UTC (Fri) by dlang (subscriber, #313) [Link]

it's actually a bit longer than these times as the speed of light you are listing is the speed of light through a vacuum, going through fiber is noticeably slower.

Examples for the speed of light

Posted Aug 10, 2012 1:30 UTC (Fri) by paulproteus (subscriber, #69280) [Link]

Interesting point!

http://blog.advaoptical.com/speed-light-fiber-first-build... suggests that one should expect approximately a 33% increase in these times for the fiber optics.

(Additionally, they should be doubled due to round-trip time, as per my follow-up comment.)

Examples for the speed of light (Correction)

Posted Aug 10, 2012 1:28 UTC (Fri) by paulproteus (subscriber, #69280) [Link]

One correction to the above note: One should *double* these numbers for *round*-trip time. These are one-way times.

Examples for the speed of light

Posted Oct 2, 2012 8:17 UTC (Tue) by ncm (subscriber, #165) [Link]

Do fibers follow great-circle routes already? I expected that to take longer to happen.

Examples for the speed of light

Posted Oct 12, 2012 12:04 UTC (Fri) by Lennie (guest, #49641) [Link]

You can see the routes here: