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Re: 923 Mbps across the Ocean ...
On Fri, Mar 07, 2003 at 10:09:51PM +0100, Mikael Abrahamsson quacked: > > On Fri, 7 Mar 2003, Richard A Steenbergen wrote: > > > Production commercial networks need not apply, 'lest someone realize that > > they blow away these speed records on a regular basis. > > What kind of production environment needs a single TCP stream of data > at 1 gigabit/s over a 150ms latency link? > > Just the fact that you need a ~20 megabyte TCP window size to achieve this > (feel free to correct me if I'm wrong here) seems kind of unusal to me. It's unusual, but it's not completely unheard of. One of the biggest sources of such data is VLBI (interferometry to measure the movement of the earth's crust), in which signals from geographically distributed measurement sites have to be recorded and correlated at a central site: http://web.haystack.edu/vlbi/vlbisystems.html The signals are massive. Right now they use specially made tape drives that can record 1Gb/s: ftp://web.haystack.edu/pub/mark4/memos/230.2.pdf ftp://web.haystack.edu/pub/mark4/memos/HDR_concept.PDF and they send the data around via airplanes. They'd love to be able to do real-time correlation of the data, but that involves collecting 6 of these feeds at a central site (more coming). The feeds must be capable of running unattended for up to 24 hours (86 terabytes each, or an aggregate of half a petabyte per day). Yes, backbones push more than a gigabit across links, but not as for a single flow of data. -Dave -- work: firstname.lastname@example.org me: email@example.com MIT Laboratory for Computer Science http://www.angio.net/ I do not accept unsolicited commercial email. Do not spam me.