60 ms cross-continent

Joe Greco jgreco at ns.sol.net
Sat Jun 20 16:29:37 UTC 2020


On Sat, Jun 20, 2020 at 09:24:11AM -0700, William Herrin wrote:
> Howdy,
> 
> Why is latency between the east and west coasts so bad? Speed of light
> accounts for about 15ms each direction for a 30ms round trip. Where
> does the other 30ms come from and why haven't we gotten rid of it?
> 
> c = 186,282 miles/second
> 2742 miles from Seattle to Washington DC mainly driving I-90
> 
> 2742/186282 ~= 0.015 seconds

Speed of light in a fiber is more like 124K miles per second.  It 
depends on the refractive index.  And of course amplifiers and stuff.

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"The strain of anti-intellectualism has been a constant thread winding its way
through our political and cultural life, nurtured by the false notion that
democracy means that 'my ignorance is just as good as your knowledge.'"-Asimov


More information about the NANOG mailing list